diff --git a/.gitignore b/.gitignore
index 1c57d4c958..41c0b20a76 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,6 +11,7 @@ git-apply
 git-archimport
 git-archive
 git-bisect
+git-bisect--helper
 git-blame
 git-branch
 git-bundle
@@ -35,6 +36,8 @@ git-diff
 git-diff-files
 git-diff-index
 git-diff-tree
+git-difftool
+git-difftool--helper
 git-describe
 git-fast-export
 git-fast-import
@@ -78,6 +81,7 @@ git-merge-recursive
 git-merge-resolve
 git-merge-subtree
 git-mergetool
+git-mergetool--lib
 git-mktag
 git-mktree
 git-name-rev
diff --git a/Documentation/RelNotes-1.6.2.4.txt b/Documentation/RelNotes-1.6.2.4.txt
new file mode 100644
index 0000000000..21bf4f3a3d
--- /dev/null
+++ b/Documentation/RelNotes-1.6.2.4.txt
@@ -0,0 +1,31 @@
+GIT v1.6.2.4 Release Notes
+==========================
+
+Fixes since v1.6.2.3
+--------------------
+
+* The configuration parser had a buffer overflow while parsing an overlong
+  value.
+
+* "git-checkout <tree-ish> <submodule>" did not update the index entry at
+  the named path; it now does.
+
+* "git init" segfaulted when given an overlong template location via
+  the --template= option.
+
+* "git-ls-tree" and "git-diff-tree" used a pathspec correctly when
+  deciding to descend into a subdirectory but they did not match the
+  individual paths correctly.  This caused pathspecs "abc/d ab" to match
+  "abc/0" ("abc/d" made them decide to descend into the directory "abc/",
+  and then "ab" incorrectly matched "abc/0" when it shouldn't).
+
+* "git-merge-recursive" was broken when a submodule entry was involved in
+  a criss-cross merge situation.
+
+Many small documentation updates are included as well.
+
+---
+exec >/var/tmp/1
+echo O=$(git describe maint)
+O=v1.6.2.3-21-ga51609a
+git shortlog --no-merges $O..maint
diff --git a/Documentation/RelNotes-1.6.3.txt b/Documentation/RelNotes-1.6.3.txt
index 839498c38a..ca38decb37 100644
--- a/Documentation/RelNotes-1.6.3.txt
+++ b/Documentation/RelNotes-1.6.3.txt
@@ -47,6 +47,8 @@ Updates since v1.6.2
 
 (usability, bells and whistles)
 
+* Boolean configuration variable yes/no can be written as on/off.
+
 * rsync:/path/to/repo can be used to run git over rsync for local
   repositories.  It may not be useful in practice; meant primarily for
   testing.
@@ -63,6 +65,9 @@ Updates since v1.6.2
 
 * "--oneline" is a synonym for "--pretty=oneline --abbrev-commit".
 
+* "--graph" to the "git log" family can draw the commit ancestry graph
+  in colors.
+
 * If you realize that you botched the patch when you are editing hunks
   with the 'edit' action in git-add -i/-p, you can abort the editor to
   tell git not to apply it.
@@ -75,8 +80,16 @@ Updates since v1.6.2
   1.6.2, but the initial implementation did not teach this to a few
   commands.  Now the syntax works with "branch -m @{-1} newname".
 
+* "git-add -p" now supports "q"uit action.
+
 * git-archive learned --output=<file> option.
 
+* git-archive takes attributes from the tree being archived; strictly
+  speaking, this is an incompatible behaviour change, but is a good one.
+  Use --worktree-attributes option to allow it to read attributes from
+  the work tree as before (deprecated git-tar tree command always reads
+  attributes from the work tree).
+
 * git-bisect shows not just the number of remaining commits whose goodness
   is unknown, but also shows the estimated number of remaining rounds.
 
@@ -93,6 +106,9 @@ Updates since v1.6.2
 
 * git-clone runs post-checkout hook when run without --no-checkout.
 
+* git-difftool is now part of the officially supported command, primarily
+  maintained by David Aguilar.
+
 * git-fast-export choked when seeing a tag that does not point at commit.
 
 * git-for-each-ref learned a new "upstream" token.
@@ -156,26 +172,18 @@ release, unless otherwise noted.
 Here are fixes that this release has, but have not been backported to
 v1.6.2.X series.
 
+* "git-apply" rejected a patch that swaps two files (i.e. renames A to B
+  and B to A at the same time).  May need to be backported by cherry
+  picking d8c81df and then 7fac0ee).
+
 * The initial checkout did not read the attributes from the .gitattribute
   file that is being checked out.
 
-* "git-checkout <tree-ish> <submodule>" did not update the index entry at
-  the named path; it now does.
-
 * git-gc spent excessive amount of time to decide if an object appears
   in a locally existing pack (if needed, backport by merging 69e020a).
 
-* "git-ls-tree" and "git-diff-tree" used a pathspec correctly when
-  deciding to descend into a subdirectory but they did not match the
-  individual paths correctly.  This caused pathspecs "abc/d ab" to match
-  "abc/0" ("abc/d" made them decide to descend into the directory "abc/",
-  and then "ab" incorrectly matched "abc/0" when it shouldn't).
-
-* "git-merge-recursive" was broken when a submodule entry was involved in
-  a criss-cross merge situation.
-
 ---
 exec >/var/tmp/1
-O=v1.6.2.3-497-g54a4749
+O=v1.6.3-rc0-74-g9824a38
 echo O=$(git describe master)
 git shortlog --no-merges $O..master ^maint
diff --git a/Documentation/config.txt b/Documentation/config.txt
index f3ebd2f9a0..5ffd14141a 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -61,7 +61,7 @@ Internal whitespace within a variable value is retained verbatim.
 
 The values following the equals sign in variable assign are all either
 a string, an integer, or a boolean.  Boolean values may be given as yes/no,
-0/1 or true/false.  Case is not significant in boolean values, when
+0/1, true/false or on/off.  Case is not significant in boolean values, when
 converting value to the canonical form using '--bool' type specifier;
 'git-config' will ensure that the output is "true" or "false".
 
@@ -667,6 +667,27 @@ diff.suppressBlankEmpty::
 	A boolean to inhibit the standard behavior of printing a space
 	before each empty output line. Defaults to false.
 
+diff.tool::
+	Controls which diff tool is used.  `diff.tool` overrides
+	`merge.tool` when used by linkgit:git-difftool[1] and has
+	the same valid values as `merge.tool` minus "tortoisemerge"
+	and plus "kompare".
+
+difftool.<tool>.path::
+	Override the path for the given tool.  This is useful in case
+	your tool is not in the PATH.
+
+difftool.<tool>.cmd::
+	Specify the command to invoke the specified diff tool.
+	The specified command is evaluated in shell with the following
+	variables available:  'LOCAL' is set to the name of the temporary
+	file containing the contents of the diff pre-image and 'REMOTE'
+	is set to the name of the temporary file containing the contents
+	of the diff post-image.
+
+difftool.prompt::
+	Prompt before each invocation of the diff tool.
+
 diff.wordRegex::
 	A POSIX Extended Regular Expression used to determine what is a "word"
 	when performing word-by-word difference calculations.  Character
diff --git a/Documentation/git-add.txt b/Documentation/git-add.txt
index ce71838b9e..d938b42289 100644
--- a/Documentation/git-add.txt
+++ b/Documentation/git-add.txt
@@ -245,8 +245,11 @@ patch::
 
        y - stage this hunk
        n - do not stage this hunk
+       q - quit, do not stage this hunk nor any of the remaining ones
        a - stage this and all the remaining hunks in the file
        d - do not stage this hunk nor any of the remaining hunks in the file
+       g - select a hunk to go to
+       / - search for a hunk matching the given regex
        j - leave this hunk undecided, see next undecided hunk
        J - leave this hunk undecided, see next hunk
        k - leave this hunk undecided, see previous undecided hunk
diff --git a/Documentation/git-archive.txt b/Documentation/git-archive.txt
index c1adf59497..bc132c87e1 100644
--- a/Documentation/git-archive.txt
+++ b/Documentation/git-archive.txt
@@ -10,7 +10,7 @@ SYNOPSIS
 --------
 [verse]
 'git archive' --format=<fmt> [--list] [--prefix=<prefix>/] [<extra>]
-	      [--output=<file>]
+	      [--output=<file>] [--worktree-attributes]
 	      [--remote=<repo> [--exec=<git-upload-archive>]] <tree-ish>
 	      [path...]
 
@@ -51,6 +51,9 @@ OPTIONS
 --output=<file>::
 	Write the archive to <file> instead of stdout.
 
+--worktree-attributes::
+	Look for attributes in .gitattributes in working directory too.
+
 <extra>::
 	This can be any options that the archiver backend understands.
 	See next section.
diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index ba3dea6840..cbd4275871 100644
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -112,19 +112,22 @@ OPTIONS
 	Display the full sha1s in the output listing rather than abbreviating them.
 
 --track::
-	When creating a new branch, set up the configuration so that 'git-pull'
-	will automatically retrieve data from the start point, which must be
-	a branch. Use this if you always pull from the same upstream branch
-	into the new branch, and if you do not want to use "git pull
-	<repository> <refspec>" explicitly. This behavior is the default
-	when the start point is a remote branch. Set the
-	branch.autosetupmerge configuration variable to `false` if you want
-	'git-checkout' and 'git-branch' to always behave as if '--no-track' were
-	given. Set it to `always` if you want this behavior when the
-	start-point is either a local or remote branch.
+	When creating a new branch, set up configuration to mark the
+	start-point branch as "upstream" from the new branch. This
+	configuration will tell git to show the relationship between the
+	two branches in `git status` and `git branch -v`. Furthermore,
+	it directs `git pull` without arguments to pull from the
+	upstream when the new branch is checked out.
++
+This behavior is the default when the start point is a remote branch.
+Set the branch.autosetupmerge configuration variable to `false` if you
+want `git checkout` and `git branch` to always behave as if '--no-track'
+were given. Set it to `always` if you want this behavior when the
+start-point is either a local or remote branch.
 
 --no-track::
-	Ignore the branch.autosetupmerge configuration variable.
+	Do not set up "upstream" configuration, even if the
+	branch.autosetupmerge configuration variable is true.
 
 --contains <commit>::
 	Only list branches which contain the specified commit.
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index 223ea9caef..ad4b31e892 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -8,22 +8,22 @@ git-checkout - Checkout a branch or paths to the working tree
 SYNOPSIS
 --------
 [verse]
-'git checkout' [-q] [-f] [-t | --track | --no-track] [-b <new_branch> [-l]] [-m] [<branch>]
+'git checkout' [-q] [-f] [-m] [<branch>]
+'git checkout' [-q] [-f] [-m] [-b <new_branch>] [<start_point>]
 'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <paths>...
 
 DESCRIPTION
 -----------
 
 When <paths> are not given, this command switches branches by
-updating the index and working tree to reflect the specified
-branch, <branch>, and updating HEAD to be <branch> or, if
-specified, <new_branch>.  Using -b will cause <new_branch> to
-be created; in this case you can use the --track or --no-track
-options, which will be passed to `git branch`.
+updating the index, working tree, and HEAD to reflect the specified
+branch.
 
-As a convenience, --track will default to creating a branch whose
-name is constructed from the specified branch name by stripping
-the first namespace level.
+If `-b` is given, a new branch is created and checked out, as if
+linkgit:git-branch[1] were called; in this case you can
+use the --track or --no-track options, which will be passed to `git
+branch`.  As a convenience, --track without `-b` implies branch
+creation; see the description of --track below.
 
 When <paths> are given, this command does *not* switch
 branches.  It updates the named paths in the working tree from
@@ -62,22 +62,12 @@ entries; instead, unmerged entries are ignored.
 
 -b::
 	Create a new branch named <new_branch> and start it at
-	<branch>.  The new branch name must pass all checks defined
-	by linkgit:git-check-ref-format[1].  Some of these checks
-	may restrict the characters allowed in a branch name.
+	<start_point>; see linkgit:git-branch[1] for details.
 
 -t::
 --track::
-	When creating a new branch, set up configuration so that 'git-pull'
-	will automatically retrieve data from the start point, which must be
-	a branch. Use this if you always pull from the same upstream branch
-	into the new branch, and if you don't want to use "git pull
-	<repository> <refspec>" explicitly. This behavior is the default
-	when the start point is a remote branch. Set the
-	branch.autosetupmerge configuration variable to `false` if you want
-	'git checkout' and 'git branch' to always behave as if '--no-track' were
-	given. Set it to `always` if you want this behavior when the
-	start point is either a local or remote branch.
+	When creating a new branch, set up "upstream" configuration. See
+	"--track" in linkgit:git-branch[1] for details.
 +
 If no '-b' option is given, the name of the new branch will be
 derived from the remote branch.  If "remotes/" or "refs/remotes/"
@@ -90,12 +80,12 @@ guessing results in an empty name, the guessing is aborted.  You can
 explicitly give a name with '-b' in such a case.
 
 --no-track::
-	Ignore the branch.autosetupmerge configuration variable.
+	Do not set up "upstream" configuration, even if the
+	branch.autosetupmerge configuration variable is true.
 
 -l::
-	Create the new branch's reflog.  This activates recording of
-	all changes made to the branch ref, enabling use of date
-	based sha1 expressions such as "<branchname>@\{yesterday}".
+	Create the new branch's reflog; see linkgit:git-branch[1] for
+	details.
 
 -m::
 --merge::
@@ -123,23 +113,28 @@ the conflicted merge in the specified paths.
 	"merge" (default) and "diff3" (in addition to what is shown by
 	"merge" style, shows the original contents).
 
+<branch>::
+	Branch to checkout; if it refers to a branch (i.e., a name that,
+	when prepended with "refs/heads/", is a valid ref), then that
+	branch is checked out. Otherwise, if it refers to a valid
+	commit, your HEAD becomes "detached" and you are no longer on
+	any branch (see below for details).
++
+As a special case, the `"@\{-N\}"` syntax for the N-th last branch
+checks out the branch (instead of detaching).  You may also specify
+`-` which is synonymous with `"@\{-1\}"`.
+
 <new_branch>::
 	Name for the new branch.
 
+<start_point>::
+	The name of a commit at which to start the new branch; see
+	linkgit:git-branch[1] for details. Defaults to HEAD.
+
 <tree-ish>::
 	Tree to checkout from (when paths are given). If not specified,
 	the index will be used.
 
-<branch>::
-	Branch to checkout (when no paths are given); may be any object
-	ID that resolves to a commit.  Defaults to HEAD.
-+
-When this parameter names a non-branch (but still a valid commit object),
-your HEAD becomes 'detached'.
-+
-As a special case, the `"@\{-N\}"` syntax for the N-th last branch
-checks out the branch (instead of detaching).  You may also specify
-`-` which is synonymous with `"@\{-1\}"`.
 
 
 Detached HEAD
diff --git a/Documentation/git-daemon.txt b/Documentation/git-daemon.txt
index 36f00aed67..a85121c689 100644
--- a/Documentation/git-daemon.txt
+++ b/Documentation/git-daemon.txt
@@ -48,7 +48,7 @@ OPTIONS
 	'git-daemon' will refuse to start when this option is enabled and no
 	whitelist is specified.
 
---base-path::
+--base-path=path::
 	Remap all the path requests as relative to the given path.
 	This is sort of "GIT root" - if you run 'git-daemon' with
 	'--base-path=/srv/git' on example.com, then if you later try to pull
@@ -81,8 +81,8 @@ OPTIONS
 	Incompatible with --port, --listen, --user and --group options.
 
 --listen=host_or_ipaddr::
-	Listen on an a specific IP address or hostname.  IP addresses can
-	be either an IPv4 address or an IPV6 address if supported.  If IPv6
+	Listen on a specific IP address or hostname.  IP addresses can
+	be either an IPv4 address or an IPv6 address if supported.  If IPv6
 	is not supported, then --listen=hostname is also not supported and
 	--listen must be given an IPv4 address.
 	Incompatible with '--inetd' option.
@@ -90,17 +90,17 @@ OPTIONS
 --port=n::
 	Listen on an alternative port.  Incompatible with '--inetd' option.
 
---init-timeout::
+--init-timeout=n::
 	Timeout between the moment the connection is established and the
 	client request is received (typically a rather low value, since
 	that should be basically immediate).
 
---timeout::
+--timeout=n::
 	Timeout for specific client sub-requests. This includes the time
-	it takes for the server to process the sub-request and time spent
-	waiting for next client's request.
+	it takes for the server to process the sub-request and the time spent
+	waiting for the next client's request.
 
---max-connections::
+--max-connections=n::
 	Maximum number of concurrent clients, defaults to 32.  Set it to
 	zero for no limit.
 
@@ -150,7 +150,7 @@ the facility of inet daemon to achieve the same before spawning
 	Enable/disable the service site-wide per default.  Note
 	that a service disabled site-wide can still be enabled
 	per repository if it is marked overridable and the
-	repository enables the service with an configuration
+	repository enables the service with a configuration
 	item.
 
 --allow-override=service::
diff --git a/contrib/difftool/git-difftool.txt b/Documentation/git-difftool.txt
similarity index 70%
rename from contrib/difftool/git-difftool.txt
rename to Documentation/git-difftool.txt
index 2b7bc03ec3..15b247bab4 100644
--- a/contrib/difftool/git-difftool.txt
+++ b/Documentation/git-difftool.txt
@@ -3,35 +3,37 @@ git-difftool(1)
 
 NAME
 ----
-git-difftool - compare changes using common merge tools
+git-difftool - Show changes using common diff tools
 
 SYNOPSIS
 --------
-'git difftool' [--tool=<tool>] [--no-prompt] ['git diff' options]
+'git difftool' [--tool=<tool>] [-y|--no-prompt|--prompt] [<'git diff' options>]
 
 DESCRIPTION
 -----------
 'git-difftool' is a git command that allows you to compare and edit files
-between revisions using common merge tools.  At its most basic level,
-'git-difftool' does what 'git-mergetool' does but its use is for non-merge
-situations such as when preparing commits or comparing changes against
-the index.
-
-'git difftool' is a frontend to 'git diff' and accepts the same
-arguments and options.
-
-See linkgit:git-diff[1] for the full list of supported options.
+between revisions using common diff tools.  'git difftool' is a frontend
+to 'git-diff' and accepts the same options and arguments.
 
 OPTIONS
 -------
+-y::
+--no-prompt::
+	Do not prompt before launching a diff tool.
+
+--prompt::
+	Prompt before each invocation of the diff tool.
+	This is the default behaviour; the option is provided to
+	override any configuration settings.
+
 -t <tool>::
 --tool=<tool>::
-	Use the merge resolution program specified by <tool>.
+	Use the diff tool specified by <tool>.
 	Valid merge tools are:
-	kdiff3, kompare, tkdiff, meld, xxdiff, emerge,
-	vimdiff, gvimdiff, ecmerge, and opendiff
+	kdiff3, kompare, tkdiff, meld, xxdiff, emerge, vimdiff, gvimdiff,
+	ecmerge, diffuse and opendiff
 +
-If a merge resolution program is not specified, 'git-difftool'
+If a diff tool is not specified, 'git-difftool'
 will use the configuration variable `diff.tool`.  If the
 configuration variable `diff.tool` is not set, 'git-difftool'
 will pick a suitable default.
@@ -42,7 +44,7 @@ can configure the absolute path to kdiff3 by setting
 `difftool.kdiff3.path`. Otherwise, 'git-difftool' assumes the
 tool is available in PATH.
 +
-Instead of running one of the known merge tool programs,
+Instead of running one of the known diff tools,
 'git-difftool' can be customized to run an alternative program
 by specifying the command line to invoke in a configuration
 variable `difftool.<tool>.cmd`.
@@ -56,8 +58,7 @@ is set to the name of the temporary file containing the contents
 of the diff post-image.  `$BASE` is provided for compatibility
 with custom merge tool commands and has the same value as `$LOCAL`.
 
---no-prompt::
-	Do not prompt before launching a diff tool.
+See linkgit:git-diff[1] for the full list of supported options.
 
 CONFIG VARIABLES
 ----------------
@@ -65,20 +66,19 @@ CONFIG VARIABLES
 difftool equivalents have not been defined.
 
 diff.tool::
-	The default merge tool to use.
+	The default diff tool to use.
 
 difftool.<tool>.path::
 	Override the path for the given tool.  This is useful in case
 	your tool is not in the PATH.
 
 difftool.<tool>.cmd::
-	Specify the command to invoke the specified merge tool.
+	Specify the command to invoke the specified diff tool.
 +
 See the `--tool=<tool>` option above for more details.
 
-merge.keepBackup::
-	The original, unedited file content can be saved to a file with
-	a `.orig` extension.  Defaults to `true` (i.e. keep the backup files).
+difftool.prompt::
+	Prompt before each invocation of the diff tool.
 
 SEE ALSO
 --------
diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index b362e9ed12..8dc873fd44 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -75,6 +75,8 @@ For all objects, the following names can be used:
 refname::
 	The name of the ref (the part after $GIT_DIR/).
 	For a non-ambiguous short name of the ref append `:short`.
+	The option core.warnAmbiguousRefs is used to select the strict
+	abbreviation mode.
 
 objecttype::
 	The type of the object (`blob`, `tree`, `commit`, `tag`).
diff --git a/Documentation/git-imap-send.txt b/Documentation/git-imap-send.txt
index 024084b8b7..d016dafd49 100644
--- a/Documentation/git-imap-send.txt
+++ b/Documentation/git-imap-send.txt
@@ -51,7 +51,7 @@ imap.host::
 imap.user::
 	The username to use when logging in to the server.
 
-imap.password::
+imap.pass::
 	The password to use when logging in to the server.
 
 imap.port::
diff --git a/Documentation/git-mergetool--lib.txt b/Documentation/git-mergetool--lib.txt
new file mode 100644
index 0000000000..78eb03f0ae
--- /dev/null
+++ b/Documentation/git-mergetool--lib.txt
@@ -0,0 +1,54 @@
+git-mergetool--lib(1)
+=====================
+
+NAME
+----
+git-mergetool--lib - Common git merge tool shell scriptlets
+
+SYNOPSIS
+--------
+'TOOL_MODE=(diff|merge) . "$(git --exec-path)/git-mergetool--lib"'
+
+DESCRIPTION
+-----------
+
+This is not a command the end user would want to run.  Ever.
+This documentation is meant for people who are studying the
+Porcelain-ish scripts and/or are writing new ones.
+
+The 'git-mergetool--lib' scriptlet is designed to be sourced (using
+`.`) by other shell scripts to set up functions for working
+with git merge tools.
+
+Before sourcing 'git-mergetool--lib', your script must set `TOOL_MODE`
+to define the operation mode for the functions listed below.
+'diff' and 'merge' are valid values.
+
+FUNCTIONS
+---------
+get_merge_tool::
+	returns a merge tool.
+
+get_merge_tool_cmd::
+	returns the custom command for a merge tool.
+
+get_merge_tool_path::
+	returns the custom path for a merge tool.
+
+run_merge_tool::
+	launches a merge tool given the tool name and a true/false
+	flag to indicate whether a merge base is present.
+	'$MERGED', '$LOCAL', '$REMOTE', and '$BASE' must be defined
+	for use by the merge tool.
+
+Author
+------
+Written by David Aguilar <davvid@gmail.com>
+
+Documentation
+--------------
+Documentation by David Aguilar and the git-list <git@vger.kernel.org>.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/git-mergetool.txt b/Documentation/git-mergetool.txt
index 5d3c632872..ff9700d17a 100644
--- a/Documentation/git-mergetool.txt
+++ b/Documentation/git-mergetool.txt
@@ -26,7 +26,8 @@ OPTIONS
 --tool=<tool>::
 	Use the merge resolution program specified by <tool>.
 	Valid merge tools are:
-	kdiff3, tkdiff, meld, xxdiff, emerge, vimdiff, gvimdiff, ecmerge, and opendiff
+	kdiff3, tkdiff, meld, xxdiff, emerge, vimdiff, gvimdiff, ecmerge,
+	diffuse, tortoisemerge and opendiff
 +
 If a merge resolution program is not specified, 'git-mergetool'
 will use the configuration variable `merge.tool`.  If the
diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index 5ed2bc840f..fba30b12ed 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -84,6 +84,11 @@ OPTIONS
 	unfortunately named tag "master"), and show them as full
 	refnames (e.g. "refs/heads/master").
 
+--abbrev-ref[={strict|loose}]::
+	A non-ambiguous short name of the objects name.
+	The option core.warnAmbiguousRefs is used to select the strict
+	abbreviation mode.
+
 --all::
 	Show all refs found in `$GIT_DIR/refs`.
 
diff --git a/Documentation/git-shell.txt b/Documentation/git-shell.txt
index 3f8d973af1..0f3ad811cf 100644
--- a/Documentation/git-shell.txt
+++ b/Documentation/git-shell.txt
@@ -18,9 +18,9 @@ of server-side GIT commands implementing the pull/push functionality.
 The commands can be executed only by the '-c' option; the shell is not
 interactive.
 
-Currently, only three commands are permitted to be called, 'git-receive-pack'
-'git-upload-pack' with a single required argument or 'cvs server' (to invoke
-'git-cvsserver').
+Currently, only four commands are permitted to be called, 'git-receive-pack'
+'git-upload-pack' and 'git-upload-archive' with a single required argument, or
+'cvs server' (to invoke 'git-cvsserver').
 
 Author
 ------
diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index b762bba759..aaa073efc8 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -297,7 +297,8 @@ for paths.
 
 Then, you would define a "diff.tex.xfuncname" configuration to
 specify a regular expression that matches a line that you would
-want to appear as the hunk header "TEXT", like this:
+want to appear as the hunk header "TEXT". Add a section to your
+`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
 
 ------------------------
 [diff "tex"]
@@ -345,7 +346,8 @@ split words in a line, by specifying an appropriate regular expression
 in the "diff.*.wordRegex" configuration variable.  For example, in TeX
 a backslash followed by a sequence of letters forms a command, but
 several such commands can be run together without intervening
-whitespace.  To separate them, use a regular expression such as
+whitespace.  To separate them, use a regular expression in your
+`$GIT_DIR/config` file (or `$HOME/.gitconfig` file) like this:
 
 ------------------------
 [diff "tex"]
@@ -373,7 +375,8 @@ resulting text on stdout.
 
 For example, to show the diff of the exif information of a
 file instead of the binary information (assuming you have the
-exif tool installed):
+exif tool installed), add the following section to your
+`$GIT_DIR/config` file (or `$HOME/.gitconfig` file):
 
 ------------------------
 [diff "jpg"]
diff --git a/Documentation/merge-config.txt b/Documentation/merge-config.txt
index 1ff08ff2cc..4832bc75e2 100644
--- a/Documentation/merge-config.txt
+++ b/Documentation/merge-config.txt
@@ -22,7 +22,8 @@ merge.stat::
 merge.tool::
 	Controls which merge resolution program is used by
 	linkgit:git-mergetool[1].  Valid built-in values are: "kdiff3",
-	"tkdiff", "meld", "xxdiff", "emerge", "vimdiff", "gvimdiff", and
+	"tkdiff", "meld", "xxdiff", "emerge", "vimdiff", "gvimdiff",
+	"diffuse", "ecmerge", "tortoisemerge", and
 	"opendiff".  Any other value is treated is custom merge tool
 	and there must be a corresponding mergetool.<tool>.cmd option.
 
diff --git a/Makefile b/Makefile
index f9c876469e..076a732c0e 100644
--- a/Makefile
+++ b/Makefile
@@ -280,12 +280,14 @@ TEST_PROGRAMS =
 
 SCRIPT_SH += git-am.sh
 SCRIPT_SH += git-bisect.sh
+SCRIPT_SH += git-difftool--helper.sh
 SCRIPT_SH += git-filter-branch.sh
 SCRIPT_SH += git-lost-found.sh
 SCRIPT_SH += git-merge-octopus.sh
 SCRIPT_SH += git-merge-one-file.sh
 SCRIPT_SH += git-merge-resolve.sh
 SCRIPT_SH += git-mergetool.sh
+SCRIPT_SH += git-mergetool--lib.sh
 SCRIPT_SH += git-parse-remote.sh
 SCRIPT_SH += git-pull.sh
 SCRIPT_SH += git-quiltimport.sh
@@ -299,6 +301,7 @@ SCRIPT_SH += git-submodule.sh
 SCRIPT_SH += git-web--browse.sh
 
 SCRIPT_PERL += git-add--interactive.perl
+SCRIPT_PERL += git-difftool.perl
 SCRIPT_PERL += git-archimport.perl
 SCRIPT_PERL += git-cvsexportcommit.perl
 SCRIPT_PERL += git-cvsimport.perl
diff --git a/archive.c b/archive.c
index 96b62d4309..b2b90d3170 100644
--- a/archive.c
+++ b/archive.c
@@ -4,6 +4,7 @@
 #include "attr.h"
 #include "archive.h"
 #include "parse-options.h"
+#include "unpack-trees.h"
 
 static char const * const archive_usage[] = {
 	"git archive [options] <tree-ish> [path...]",
@@ -150,6 +151,8 @@ int write_archive_entries(struct archiver_args *args,
 		write_archive_entry_fn_t write_entry)
 {
 	struct archiver_context context;
+	struct unpack_trees_options opts;
+	struct tree_desc t;
 	int err;
 
 	if (args->baselen > 0 && args->base[args->baselen - 1] == '/') {
@@ -168,6 +171,22 @@ int write_archive_entries(struct archiver_args *args,
 	context.args = args;
 	context.write_entry = write_entry;
 
+	/*
+	 * Setup index and instruct attr to read index only
+	 */
+	if (!args->worktree_attributes) {
+		memset(&opts, 0, sizeof(opts));
+		opts.index_only = 1;
+		opts.head_idx = -1;
+		opts.src_index = &the_index;
+		opts.dst_index = &the_index;
+		opts.fn = oneway_merge;
+		init_tree_desc(&t, args->tree->buffer, args->tree->size);
+		if (unpack_trees(1, &t, &opts))
+			return -1;
+		git_attr_set_direction(GIT_ATTR_INDEX, &the_index);
+	}
+
 	err =  read_tree_recursive(args->tree, args->base, args->baselen, 0,
 			args->pathspec, write_archive_entry, &context);
 	if (err == READ_TREE_RECURSIVE)
@@ -258,6 +277,7 @@ static int parse_archive_args(int argc, const char **argv,
 	int verbose = 0;
 	int i;
 	int list = 0;
+	int worktree_attributes = 0;
 	struct option opts[] = {
 		OPT_GROUP(""),
 		OPT_STRING(0, "format", &format, "fmt", "archive format"),
@@ -265,6 +285,8 @@ static int parse_archive_args(int argc, const char **argv,
 			"prepend prefix to each pathname in the archive"),
 		OPT_STRING(0, "output", &output, "file",
 			"write the archive to this file"),
+		OPT_BOOLEAN(0, "worktree-attributes", &worktree_attributes,
+			"read .gitattributes in working directory"),
 		OPT__VERBOSE(&verbose),
 		OPT__COMPR('0', &compression_level, "store only", 0),
 		OPT__COMPR('1', &compression_level, "compress faster", 1),
@@ -324,6 +346,7 @@ static int parse_archive_args(int argc, const char **argv,
 	args->verbose = verbose;
 	args->base = base;
 	args->baselen = strlen(base);
+	args->worktree_attributes = worktree_attributes;
 
 	return argc;
 }
diff --git a/archive.h b/archive.h
index 0b15b35143..038ac353d4 100644
--- a/archive.h
+++ b/archive.h
@@ -10,6 +10,7 @@ struct archiver_args {
 	time_t time;
 	const char **pathspec;
 	unsigned int verbose : 1;
+	unsigned int worktree_attributes : 1;
 	int compression_level;
 };
 
diff --git a/attr.c b/attr.c
index 43259e5b01..f1ca4f5859 100644
--- a/attr.c
+++ b/attr.c
@@ -405,7 +405,7 @@ static struct attr_stack *read_attr(const char *path, int macro_ok)
 		if (!res)
 			res = read_attr_from_file(path, macro_ok);
 	}
-	else {
+	else if (direction == GIT_ATTR_CHECKIN) {
 		res = read_attr_from_file(path, macro_ok);
 		if (!res)
 			/*
@@ -415,6 +415,8 @@ static struct attr_stack *read_attr(const char *path, int macro_ok)
 			 */
 			res = read_attr_from_index(path, macro_ok);
 	}
+	else
+		res = read_attr_from_index(path, macro_ok);
 	if (!res)
 		res = xcalloc(1, sizeof(*res));
 	return res;
@@ -466,7 +468,7 @@ static void bootstrap_attr_stack(void)
 		elem->prev = attr_stack;
 		attr_stack = elem;
 
-		if (!is_bare_repository()) {
+		if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
 			elem = read_attr(GITATTRIBUTES_FILE, 1);
 			elem->origin = strdup("");
 			elem->prev = attr_stack;
@@ -533,7 +535,7 @@ static void prepare_attr_stack(const char *path, int dirlen)
 	/*
 	 * Read from parent directories and push them down
 	 */
-	if (!is_bare_repository()) {
+	if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
 		while (1) {
 			char *cp;
 
@@ -674,6 +676,10 @@ int git_checkattr(const char *path, int num, struct git_attr_check *check)
 void git_attr_set_direction(enum git_attr_direction new, struct index_state *istate)
 {
 	enum git_attr_direction old = direction;
+
+	if (is_bare_repository() && new != GIT_ATTR_INDEX)
+		die("BUG: non-INDEX attr direction in a bare repo");
+
 	direction = new;
 	if (new != old)
 		drop_attr_stack();
diff --git a/attr.h b/attr.h
index 3a2f4ec1a0..69b5767ebc 100644
--- a/attr.h
+++ b/attr.h
@@ -33,7 +33,8 @@ int git_checkattr(const char *path, int, struct git_attr_check *);
 
 enum git_attr_direction {
 	GIT_ATTR_CHECKIN,
-	GIT_ATTR_CHECKOUT
+	GIT_ATTR_CHECKOUT,
+	GIT_ATTR_INDEX,
 };
 void git_attr_set_direction(enum git_attr_direction, struct index_state *);
 
diff --git a/builtin-apply.c b/builtin-apply.c
index 1926cd8055..7b404ef660 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c
@@ -2271,6 +2271,25 @@ static struct patch *in_fn_table(const char *name)
 	return NULL;
 }
 
+/*
+ * item->util in the filename table records the status of the path.
+ * Usually it points at a patch (whose result records the contents
+ * of it after applying it), but it could be PATH_WAS_DELETED for a
+ * path that a previously applied patch has already removed.
+ */
+ #define PATH_TO_BE_DELETED ((struct patch *) -2)
+#define PATH_WAS_DELETED ((struct patch *) -1)
+
+static int to_be_deleted(struct patch *patch)
+{
+	return patch == PATH_TO_BE_DELETED;
+}
+
+static int was_deleted(struct patch *patch)
+{
+	return patch == PATH_WAS_DELETED;
+}
+
 static void add_to_fn_table(struct patch *patch)
 {
 	struct string_list_item *item;
@@ -2291,7 +2310,22 @@ static void add_to_fn_table(struct patch *patch)
 	 */
 	if ((patch->new_name == NULL) || (patch->is_rename)) {
 		item = string_list_insert(patch->old_name, &fn_table);
-		item->util = (struct patch *) -1;
+		item->util = PATH_WAS_DELETED;
+	}
+}
+
+static void prepare_fn_table(struct patch *patch)
+{
+	/*
+	 * store information about incoming file deletion
+	 */
+	while (patch) {
+		if ((patch->new_name == NULL) || (patch->is_rename)) {
+			struct string_list_item *item;
+			item = string_list_insert(patch->old_name, &fn_table);
+			item->util = PATH_TO_BE_DELETED;
+		}
+		patch = patch->next;
 	}
 }
 
@@ -2304,8 +2338,8 @@ static int apply_data(struct patch *patch, struct stat *st, struct cache_entry *
 	struct patch *tpatch;
 
 	if (!(patch->is_copy || patch->is_rename) &&
-	    ((tpatch = in_fn_table(patch->old_name)) != NULL)) {
-		if (tpatch == (struct patch *) -1) {
+	    (tpatch = in_fn_table(patch->old_name)) != NULL && !to_be_deleted(tpatch)) {
+		if (was_deleted(tpatch)) {
 			return error("patch %s has been renamed/deleted",
 				patch->old_name);
 		}
@@ -2399,10 +2433,9 @@ static int check_preimage(struct patch *patch, struct cache_entry **ce, struct s
 	assert(patch->is_new <= 0);
 
 	if (!(patch->is_copy || patch->is_rename) &&
-	    (tpatch = in_fn_table(old_name)) != NULL) {
-		if (tpatch == (struct patch *) -1) {
+	    (tpatch = in_fn_table(old_name)) != NULL && !to_be_deleted(tpatch)) {
+		if (was_deleted(tpatch))
 			return error("%s: has been deleted/renamed", old_name);
-		}
 		st_mode = tpatch->new_mode;
 	} else if (!cached) {
 		stat_ret = lstat(old_name, st);
@@ -2410,6 +2443,9 @@ static int check_preimage(struct patch *patch, struct cache_entry **ce, struct s
 			return error("%s: %s", old_name, strerror(errno));
 	}
 
+	if (to_be_deleted(tpatch))
+		tpatch = NULL;
+
 	if (check_index && !tpatch) {
 		int pos = cache_name_pos(old_name, strlen(old_name));
 		if (pos < 0) {
@@ -2471,6 +2507,7 @@ static int check_patch(struct patch *patch)
 	const char *new_name = patch->new_name;
 	const char *name = old_name ? old_name : new_name;
 	struct cache_entry *ce = NULL;
+	struct patch *tpatch;
 	int ok_if_exists;
 	int status;
 
@@ -2481,7 +2518,8 @@ static int check_patch(struct patch *patch)
 		return status;
 	old_name = patch->old_name;
 
-	if (in_fn_table(new_name) == (struct patch *) -1)
+	if ((tpatch = in_fn_table(new_name)) &&
+			(was_deleted(tpatch) || to_be_deleted(tpatch)))
 		/*
 		 * A type-change diff is always split into a patch to
 		 * delete old, immediately followed by a patch to
@@ -2533,6 +2571,7 @@ static int check_patch_list(struct patch *patch)
 {
 	int err = 0;
 
+	prepare_fn_table(patch);
 	while (patch) {
 		if (apply_verbosely)
 			say_patch_name(stderr,
diff --git a/builtin-branch.c b/builtin-branch.c
index 3275821696..91098ca9b1 100644
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -311,14 +311,14 @@ static void fill_tracking_info(struct strbuf *stat, const char *branch_name,
 		if (branch && branch->merge && branch->merge[0]->dst &&
 		    show_upstream_ref)
 			strbuf_addf(stat, "[%s] ",
-			    shorten_unambiguous_ref(branch->merge[0]->dst));
+			    shorten_unambiguous_ref(branch->merge[0]->dst, 0));
 		return;
 	}
 
 	strbuf_addch(stat, '[');
 	if (show_upstream_ref)
 		strbuf_addf(stat, "%s: ",
-			shorten_unambiguous_ref(branch->merge[0]->dst));
+			shorten_unambiguous_ref(branch->merge[0]->dst, 0));
 	if (!ours)
 		strbuf_addf(stat, "behind %d] ", theirs);
 	else if (!theirs)
diff --git a/builtin-for-each-ref.c b/builtin-for-each-ref.c
index c8114c8afd..91e8f95fd2 100644
--- a/builtin-for-each-ref.c
+++ b/builtin-for-each-ref.c
@@ -601,7 +601,8 @@ static void populate_value(struct refinfo *ref)
 		if (formatp) {
 			formatp++;
 			if (!strcmp(formatp, "short"))
-				refname = shorten_unambiguous_ref(refname);
+				refname = shorten_unambiguous_ref(refname,
+						      warn_ambiguous_refs);
 			else
 				die("unknown %.*s format %s",
 				    (int)(formatp - name), name, formatp);
@@ -917,6 +918,9 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 		sort = default_sort();
 	sort_atom_limit = used_atom_cnt;
 
+	/* for warn_ambiguous_refs */
+	git_config(git_default_config, NULL);
+
 	memset(&cbdata, 0, sizeof(cbdata));
 	cbdata.grab_pattern = argv;
 	for_each_ref(grab_single_ref, &cbdata);
diff --git a/builtin-init-db.c b/builtin-init-db.c
index 4e02b33bb7..d1fa12a59e 100644
--- a/builtin-init-db.c
+++ b/builtin-init-db.c
@@ -122,8 +122,10 @@ static void copy_templates(const char *template_dir)
 		template_dir = system_path(DEFAULT_GIT_TEMPLATE_DIR);
 	if (!template_dir[0])
 		return;
+	template_len = strlen(template_dir);
+	if (PATH_MAX <= (template_len+strlen("/config")))
+		die("insanely long template path %s", template_dir);
 	strcpy(template_path, template_dir);
-	template_len = strlen(template_path);
 	if (template_path[template_len-1] != '/') {
 		template_path[template_len++] = '/';
 		template_path[template_len] = 0;
diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c
index d3360ac1f8..419f29aa1a 100644
--- a/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@ -1907,13 +1907,19 @@ static void show_commit(struct commit *commit, void *data)
 	commit->object.flags |= OBJECT_ADDED;
 }
 
-static void show_object(struct object_array_entry *p, void *data)
+static void show_object(struct object *obj, const struct name_path *path, const char *last)
 {
-	add_preferred_base_object(p->name);
-	add_object_entry(p->item->sha1, p->item->type, p->name, 0);
-	p->item->flags |= OBJECT_ADDED;
-	free((char *)p->name);
-	p->name = NULL;
+	char *name = path_name(path, last);
+
+	add_preferred_base_object(name);
+	add_object_entry(obj->sha1, obj->type, name, 0);
+	obj->flags |= OBJECT_ADDED;
+
+	/*
+	 * We will have generated the hash from the name,
+	 * but not saved a pointer to it - we can free it
+	 */
+	free((char *)name);
 }
 
 static void show_edge(struct commit *commit)
diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index 193993cf44..38a8f234de 100644
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -156,27 +156,29 @@ static void finish_commit(struct commit *commit, void *data)
 	commit->buffer = NULL;
 }
 
-static void finish_object(struct object_array_entry *p, void *data)
+static void finish_object(struct object *obj, const struct name_path *path, const char *name)
 {
-	if (p->item->type == OBJ_BLOB && !has_sha1_file(p->item->sha1))
-		die("missing blob object '%s'", sha1_to_hex(p->item->sha1));
+	if (obj->type == OBJ_BLOB && !has_sha1_file(obj->sha1))
+		die("missing blob object '%s'", sha1_to_hex(obj->sha1));
 }
 
-static void show_object(struct object_array_entry *p, void *data)
+static void show_object(struct object *obj, const struct name_path *path, const char *component)
 {
+	char *name = path_name(path, component);
 	/* An object with name "foo\n0000000..." can be used to
 	 * confuse downstream "git pack-objects" very badly.
 	 */
-	const char *ep = strchr(p->name, '\n');
+	const char *ep = strchr(name, '\n');
 
-	finish_object(p, data);
+	finish_object(obj, path, name);
 	if (ep) {
-		printf("%s %.*s\n", sha1_to_hex(p->item->sha1),
-		       (int) (ep - p->name),
-		       p->name);
+		printf("%s %.*s\n", sha1_to_hex(obj->sha1),
+		       (int) (ep - name),
+		       name);
 	}
 	else
-		printf("%s %s\n", sha1_to_hex(p->item->sha1), p->name);
+		printf("%s %s\n", sha1_to_hex(obj->sha1), name);
+	free(name);
 }
 
 static void show_edge(struct commit *commit)
diff --git a/builtin-rev-parse.c b/builtin-rev-parse.c
index 81d5a6ffc9..22c6d6ad16 100644
--- a/builtin-rev-parse.c
+++ b/builtin-rev-parse.c
@@ -26,6 +26,8 @@ static int show_type = NORMAL;
 #define SHOW_SYMBOLIC_FULL 2
 static int symbolic;
 static int abbrev;
+static int abbrev_ref;
+static int abbrev_ref_strict;
 static int output_sq;
 
 /*
@@ -109,8 +111,8 @@ static void show_rev(int type, const unsigned char *sha1, const char *name)
 		return;
 	def = NULL;
 
-	if (symbolic && name) {
-		if (symbolic == SHOW_SYMBOLIC_FULL) {
+	if ((symbolic || abbrev_ref) && name) {
+		if (symbolic == SHOW_SYMBOLIC_FULL || abbrev_ref) {
 			unsigned char discard[20];
 			char *full;
 
@@ -125,6 +127,9 @@ static void show_rev(int type, const unsigned char *sha1, const char *name)
 				 */
 				break;
 			case 1: /* happy */
+				if (abbrev_ref)
+					full = shorten_unambiguous_ref(full,
+						abbrev_ref_strict);
 				show_with_type(type, full);
 				break;
 			default: /* ambiguous */
@@ -506,6 +511,20 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 				symbolic = SHOW_SYMBOLIC_FULL;
 				continue;
 			}
+			if (!prefixcmp(arg, "--abbrev-ref") &&
+			    (!arg[12] || arg[12] == '=')) {
+				abbrev_ref = 1;
+				abbrev_ref_strict = warn_ambiguous_refs;
+				if (arg[12] == '=') {
+					if (!strcmp(arg + 13, "strict"))
+						abbrev_ref_strict = 1;
+					else if (!strcmp(arg + 13, "loose"))
+						abbrev_ref_strict = 0;
+					else
+						die("unknown mode for %s", arg);
+				}
+				continue;
+			}
 			if (!strcmp(arg, "--all")) {
 				for_each_ref(show_reference, NULL);
 				continue;
diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
index 0713bca778..f88e721936 100644
--- a/builtin-tar-tree.c
+++ b/builtin-tar-tree.c
@@ -24,7 +24,7 @@ int cmd_tar_tree(int argc, const char **argv, const char *prefix)
 	 * 	git archive --format-tar --prefix=basedir tree-ish
 	 */
 	int i;
-	const char **nargv = xcalloc(sizeof(*nargv), argc + 2);
+	const char **nargv = xcalloc(sizeof(*nargv), argc + 3);
 	char *basedir_arg;
 	int nargc = 0;
 
@@ -36,6 +36,13 @@ int cmd_tar_tree(int argc, const char **argv, const char *prefix)
 		argv++;
 		argc--;
 	}
+
+	/*
+	 * Because it's just a compatibility wrapper, tar-tree supports only
+	 * the old behaviour of reading attributes from the work tree.
+	 */
+	nargv[nargc++] = "--worktree-attributes";
+
 	switch (argc) {
 	default:
 		usage(tar_tree_usage);
diff --git a/color.h b/color.h
index 6846be1706..18abeb7c7d 100644
--- a/color.h
+++ b/color.h
@@ -11,6 +11,7 @@
 #define GIT_COLOR_GREEN		"\033[32m"
 #define GIT_COLOR_YELLOW	"\033[33m"
 #define GIT_COLOR_BLUE		"\033[34m"
+#define GIT_COLOR_MAGENTA	"\033[35m"
 #define GIT_COLOR_CYAN		"\033[36m"
 #define GIT_COLOR_BG_RED	"\033[41m"
 
diff --git a/command-list.txt b/command-list.txt
index 3583a33ee9..fb03a2ebb5 100644
--- a/command-list.txt
+++ b/command-list.txt
@@ -33,6 +33,7 @@ git-diff                                mainporcelain common
 git-diff-files                          plumbinginterrogators
 git-diff-index                          plumbinginterrogators
 git-diff-tree                           plumbinginterrogators
+git-difftool                            ancillaryinterrogators
 git-fast-export				ancillarymanipulators
 git-fast-import				ancillarymanipulators
 git-fetch                               mainporcelain common
diff --git a/config.c b/config.c
index b76fe4c6dc..8c1ae598a9 100644
--- a/config.c
+++ b/config.c
@@ -51,7 +51,7 @@ static char *parse_value(void)
 
 	for (;;) {
 		int c = get_next_char();
-		if (len >= sizeof(value))
+		if (len >= sizeof(value) - 1)
 			return NULL;
 		if (c == '\n') {
 			if (quote)
@@ -331,9 +331,9 @@ int git_config_bool_or_int(const char *name, const char *value, int *is_bool)
 		return 1;
 	if (!*value)
 		return 0;
-	if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
+	if (!strcasecmp(value, "true") || !strcasecmp(value, "yes") || !strcasecmp(value, "on"))
 		return 1;
-	if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
+	if (!strcasecmp(value, "false") || !strcasecmp(value, "no") || !strcasecmp(value, "off"))
 		return 0;
 	*is_bool = 0;
 	return git_config_int(name, value);
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index c1c879821d..1a90cb87f5 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -910,6 +910,26 @@ _git_diff ()
 	__git_complete_file
 }
 
+__git_mergetools_common="diffuse ecmerge emerge kdiff3 meld opendiff
+			tkdiff vimdiff gvimdiff xxdiff
+"
+
+_git_difftool ()
+{
+	local cur="${COMP_WORDS[COMP_CWORD]}"
+	case "$cur" in
+	--tool=*)
+		__gitcomp "$__git_mergetools_common kompare" "" "${cur##--tool=}"
+		return
+		;;
+	--*)
+		__gitcomp "--tool="
+		return
+		;;
+	esac
+	COMPREPLY=()
+}
+
 __git_fetch_options="
 	--quiet --verbose --append --upload-pack --force --keep --depth=
 	--tags --no-tags
@@ -1172,10 +1192,7 @@ _git_mergetool ()
 	local cur="${COMP_WORDS[COMP_CWORD]}"
 	case "$cur" in
 	--tool=*)
-		__gitcomp "
-			kdiff3 tkdiff meld xxdiff emerge
-			vimdiff gvimdiff ecmerge opendiff
-			" "" "${cur##--tool=}"
+		__gitcomp "$__git_mergetools_common tortoisemerge" "" "${cur##--tool=}"
 		return
 		;;
 	--*)
@@ -1901,6 +1918,7 @@ _git ()
 	config)      _git_config ;;
 	describe)    _git_describe ;;
 	diff)        _git_diff ;;
+	difftool)    _git_difftool ;;
 	fetch)       _git_fetch ;;
 	format-patch) _git_format_patch ;;
 	fsck)        _git_fsck ;;
diff --git a/contrib/difftool/git-difftool-helper b/contrib/difftool/git-difftool-helper
deleted file mode 100755
index 9c0a13452a..0000000000
--- a/contrib/difftool/git-difftool-helper
+++ /dev/null
@@ -1,249 +0,0 @@
-#!/bin/sh
-# git-difftool-helper is a GIT_EXTERNAL_DIFF-compatible diff tool launcher.
-# It supports kdiff3, kompare, tkdiff, xxdiff, meld, opendiff,
-# emerge, ecmerge, vimdiff, gvimdiff, and custom user-configurable tools.
-# This script is typically launched by using the 'git difftool'
-# convenience command.
-#
-# Copyright (c) 2009 David Aguilar
-
-# Set GIT_DIFFTOOL_NO_PROMPT to bypass the per-file prompt.
-should_prompt () {
-	! test -n "$GIT_DIFFTOOL_NO_PROMPT"
-}
-
-# Should we keep the backup .orig file?
-keep_backup_mode="$(git config --bool merge.keepBackup || echo true)"
-keep_backup () {
-	test "$keep_backup_mode" = "true"
-}
-
-# This function manages the backup .orig file.
-# A backup $MERGED.orig file is created if changes are detected.
-cleanup_temp_files () {
-	if test -n "$MERGED"; then
-		if keep_backup && test "$MERGED" -nt "$BACKUP"; then
-			test -f "$BACKUP" && mv -- "$BACKUP" "$MERGED.orig"
-		else
-			rm -f -- "$BACKUP"
-		fi
-	fi
-}
-
-# This is called when users Ctrl-C out of git-difftool-helper
-sigint_handler () {
-	cleanup_temp_files
-	exit 1
-}
-
-# This function prepares temporary files and launches the appropriate
-# merge tool.
-launch_merge_tool () {
-	# Merged is the filename as it appears in the work tree
-	# Local is the contents of a/filename
-	# Remote is the contents of b/filename
-	# Custom merge tool commands might use $BASE so we provide it
-	MERGED="$1"
-	LOCAL="$2"
-	REMOTE="$3"
-	BASE="$1"
-	ext="$$$(expr "$MERGED" : '.*\(\.[^/]*\)$')"
-	BACKUP="$MERGED.BACKUP.$ext"
-
-	# Create and ensure that we clean up $BACKUP
-	test -f "$MERGED" && cp -- "$MERGED" "$BACKUP"
-	trap sigint_handler INT
-
-	# $LOCAL and $REMOTE are temporary files so prompt
-	# the user with the real $MERGED name before launching $merge_tool.
-	if should_prompt; then
-		printf "\nViewing: '$MERGED'\n"
-		printf "Hit return to launch '%s': " "$merge_tool"
-		read ans
-	fi
-
-	# Run the appropriate merge tool command
-	case "$merge_tool" in
-	kdiff3)
-		basename=$(basename "$MERGED")
-		"$merge_tool_path" --auto \
-			--L1 "$basename (A)" \
-			--L2 "$basename (B)" \
-			-o "$MERGED" "$LOCAL" "$REMOTE" \
-			> /dev/null 2>&1
-		;;
-
-	kompare)
-		"$merge_tool_path" "$LOCAL" "$REMOTE"
-		;;
-
-	tkdiff)
-		"$merge_tool_path" -o "$MERGED" "$LOCAL" "$REMOTE"
-		;;
-
-	meld)
-		"$merge_tool_path" "$LOCAL" "$REMOTE"
-		;;
-
-	vimdiff)
-		"$merge_tool_path" -c "wincmd l" "$LOCAL" "$REMOTE"
-		;;
-
-	gvimdiff)
-		"$merge_tool_path" -c "wincmd l" -f "$LOCAL" "$REMOTE"
-		;;
-
-	xxdiff)
-		"$merge_tool_path" \
-			-X \
-			-R 'Accel.SaveAsMerged: "Ctrl-S"' \
-			-R 'Accel.Search: "Ctrl+F"' \
-			-R 'Accel.SearchForward: "Ctrl-G"' \
-			--merged-file "$MERGED" \
-			"$LOCAL" "$REMOTE"
-		;;
-
-	opendiff)
-		"$merge_tool_path" "$LOCAL" "$REMOTE" \
-			-merge "$MERGED" | cat
-		;;
-
-	ecmerge)
-		"$merge_tool_path" "$LOCAL" "$REMOTE" \
-			--default --mode=merge2 --to="$MERGED"
-		;;
-
-	emerge)
-		"$merge_tool_path" -f emerge-files-command \
-			"$LOCAL" "$REMOTE" "$(basename "$MERGED")"
-		;;
-
-	*)
-		if test -n "$merge_tool_cmd"; then
-			( eval $merge_tool_cmd )
-		fi
-		;;
-	esac
-
-	cleanup_temp_files
-}
-
-# Verifies that (difftool|mergetool).<tool>.cmd exists
-valid_custom_tool() {
-	merge_tool_cmd="$(git config difftool.$1.cmd)"
-	test -z "$merge_tool_cmd" &&
-	merge_tool_cmd="$(git config mergetool.$1.cmd)"
-	test -n "$merge_tool_cmd"
-}
-
-# Verifies that the chosen merge tool is properly setup.
-# Built-in merge tools are always valid.
-valid_tool() {
-	case "$1" in
-	kdiff3 | kompare | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff | ecmerge)
-		;; # happy
-	*)
-		if ! valid_custom_tool "$1"
-		then
-			return 1
-		fi
-		;;
-	esac
-}
-
-# Sets up the merge_tool_path variable.
-# This handles the difftool.<tool>.path configuration.
-# This also falls back to mergetool defaults.
-init_merge_tool_path() {
-	merge_tool_path=$(git config difftool."$1".path)
-	test -z "$merge_tool_path" &&
-	merge_tool_path=$(git config mergetool."$1".path)
-	if test -z "$merge_tool_path"; then
-		case "$1" in
-		emerge)
-			merge_tool_path=emacs
-			;;
-		*)
-			merge_tool_path="$1"
-			;;
-		esac
-	fi
-}
-
-# Allow GIT_DIFF_TOOL and GIT_MERGE_TOOL to provide default values
-test -n "$GIT_MERGE_TOOL" && merge_tool="$GIT_MERGE_TOOL"
-test -n "$GIT_DIFF_TOOL" && merge_tool="$GIT_DIFF_TOOL"
-
-# If merge tool was not specified then use the diff.tool
-# configuration variable.  If that's invalid then reset merge_tool.
-# Fallback to merge.tool.
-if test -z "$merge_tool"; then
-	merge_tool=$(git config diff.tool)
-	test -z "$merge_tool" &&
-	merge_tool=$(git config merge.tool)
-	if test -n "$merge_tool" && ! valid_tool "$merge_tool"; then
-		echo >&2 "git config option diff.tool set to unknown tool: $merge_tool"
-		echo >&2 "Resetting to default..."
-		unset merge_tool
-	fi
-fi
-
-# Try to guess an appropriate merge tool if no tool has been set.
-if test -z "$merge_tool"; then
-	# We have a $DISPLAY so try some common UNIX merge tools
-	if test -n "$DISPLAY"; then
-		# If gnome then prefer meld, otherwise, prefer kdiff3 or kompare
-		if test -n "$GNOME_DESKTOP_SESSION_ID" ; then
-			merge_tool_candidates="meld kdiff3 kompare tkdiff xxdiff gvimdiff"
-		else
-			merge_tool_candidates="kdiff3 kompare tkdiff xxdiff meld gvimdiff"
-		fi
-	fi
-	if echo "${VISUAL:-$EDITOR}" | grep 'emacs' > /dev/null 2>&1; then
-		# $EDITOR is emacs so add emerge as a candidate
-		merge_tool_candidates="$merge_tool_candidates emerge opendiff vimdiff"
-	elif echo "${VISUAL:-$EDITOR}" | grep 'vim' > /dev/null 2>&1; then
-		# $EDITOR is vim so add vimdiff as a candidate
-		merge_tool_candidates="$merge_tool_candidates vimdiff opendiff emerge"
-	else
-		merge_tool_candidates="$merge_tool_candidates opendiff emerge vimdiff"
-	fi
-	echo "merge tool candidates: $merge_tool_candidates"
-
-	# Loop over each candidate and stop when a valid merge tool is found.
-	for i in $merge_tool_candidates
-	do
-		init_merge_tool_path $i
-		if type "$merge_tool_path" > /dev/null 2>&1; then
-			merge_tool=$i
-			break
-		fi
-	done
-
-	if test -z "$merge_tool" ; then
-		echo "No known merge resolution program available."
-		exit 1
-	fi
-
-else
-	# A merge tool has been set, so verify that it's valid.
-	if ! valid_tool "$merge_tool"; then
-		echo >&2 "Unknown merge tool $merge_tool"
-		exit 1
-	fi
-
-	init_merge_tool_path "$merge_tool"
-
-	if test -z "$merge_tool_cmd" && ! type "$merge_tool_path" > /dev/null 2>&1; then
-		echo "The merge tool $merge_tool is not available as '$merge_tool_path'"
-		exit 1
-	fi
-fi
-
-
-# Launch the merge tool on each path provided by 'git diff'
-while test $# -gt 6
-do
-	launch_merge_tool "$1" "$2" "$5"
-	shift 7
-done
diff --git a/git-add--interactive.perl b/git-add--interactive.perl
index def062a9e2..60dd1b5be2 100755
--- a/git-add--interactive.perl
+++ b/git-add--interactive.perl
@@ -620,11 +620,12 @@ sub parse_diff {
 	if ($diff_use_color) {
 		@colored = run_cmd_pipe(qw(git diff-files -p --color --), $path);
 	}
-	my (@hunk) = { TEXT => [], DISPLAY => [] };
+	my (@hunk) = { TEXT => [], DISPLAY => [], TYPE => 'header' };
 
 	for (my $i = 0; $i < @diff; $i++) {
 		if ($diff[$i] =~ /^@@ /) {
-			push @hunk, { TEXT => [], DISPLAY => [] };
+			push @hunk, { TEXT => [], DISPLAY => [],
+				TYPE => 'hunk' };
 		}
 		push @{$hunk[-1]{TEXT}}, $diff[$i];
 		push @{$hunk[-1]{DISPLAY}},
@@ -636,8 +637,8 @@ sub parse_diff {
 sub parse_diff_header {
 	my $src = shift;
 
-	my $head = { TEXT => [], DISPLAY => [] };
-	my $mode = { TEXT => [], DISPLAY => [] };
+	my $head = { TEXT => [], DISPLAY => [], TYPE => 'header' };
+	my $mode = { TEXT => [], DISPLAY => [], TYPE => 'mode' };
 
 	for (my $i = 0; $i < @{$src->{TEXT}}; $i++) {
 		my $dest = $src->{TEXT}->[$i] =~ /^(old|new) mode (\d+)$/ ?
@@ -684,6 +685,7 @@ sub split_hunk {
 		my $this = +{
 			TEXT => [],
 			DISPLAY => [],
+			TYPE => 'hunk',
 			OLD => $o_ofs,
 			NEW => $n_ofs,
 			OCNT => 0,
@@ -873,7 +875,11 @@ sub edit_hunk_loop {
 		if (!defined $text) {
 			return undef;
 		}
-		my $newhunk = { TEXT => $text, USE => 1 };
+		my $newhunk = {
+			TEXT => $text,
+			TYPE => $hunk->[$ix]->{TYPE},
+			USE => 1
+		};
 		if (diff_applies($head,
 				 @{$hunk}[0..$ix-1],
 				 $newhunk,
@@ -894,6 +900,7 @@ sub help_patch_cmd {
 	print colored $help_color, <<\EOF ;
 y - stage this hunk
 n - do not stage this hunk
+q - quit, do not stage this hunk nor any of the remaining ones
 a - stage this and all the remaining hunks in the file
 d - do not stage this hunk nor any of the remaining hunks in the file
 g - select a hunk to go to
@@ -930,7 +937,7 @@ sub patch_update_cmd {
 					@mods);
 	}
 	for (@them) {
-		patch_update_file($_->{VALUE});
+		return 0 if patch_update_file($_->{VALUE});
 	}
 }
 
@@ -976,6 +983,7 @@ sub display_hunks {
 }
 
 sub patch_update_file {
+	my $quit = 0;
 	my ($ix, $num);
 	my $path = shift;
 	my ($head, @hunk) = parse_diff($path);
@@ -985,32 +993,7 @@ sub patch_update_file {
 	}
 
 	if (@{$mode->{TEXT}}) {
-		while (1) {
-			print @{$mode->{DISPLAY}};
-			print colored $prompt_color,
-				"Stage mode change [y/n/a/d/?]? ";
-			my $line = prompt_single_character;
-			if ($line =~ /^y/i) {
-				$mode->{USE} = 1;
-				last;
-			}
-			elsif ($line =~ /^n/i) {
-				$mode->{USE} = 0;
-				last;
-			}
-			elsif ($line =~ /^a/i) {
-				$_->{USE} = 1 foreach ($mode, @hunk);
-				last;
-			}
-			elsif ($line =~ /^d/i) {
-				$_->{USE} = 0 foreach ($mode, @hunk);
-				last;
-			}
-			else {
-				help_patch_cmd('');
-				next;
-			}
-		}
+		unshift @hunk, $mode;
 	}
 
 	$num = scalar @hunk;
@@ -1054,14 +1037,19 @@ sub patch_update_file {
 		}
 		last if (!$undecided);
 
-		if (hunk_splittable($hunk[$ix]{TEXT})) {
+		if ($hunk[$ix]{TYPE} eq 'hunk' &&
+		    hunk_splittable($hunk[$ix]{TEXT})) {
 			$other .= ',s';
 		}
-		$other .= ',e';
+		if ($hunk[$ix]{TYPE} eq 'hunk') {
+			$other .= ',e';
+		}
 		for (@{$hunk[$ix]{DISPLAY}}) {
 			print;
 		}
-		print colored $prompt_color, "Stage this hunk [y,n,a,d,/$other,?]? ";
+		print colored $prompt_color, 'Stage ',
+		  ($hunk[$ix]{TYPE} eq 'mode' ? 'mode change' : 'this hunk'),
+		  " [y,n,a,d,/$other,?]? ";
 		my $line = prompt_single_character;
 		if ($line) {
 			if ($line =~ /^y/i) {
@@ -1113,6 +1101,16 @@ sub patch_update_file {
 				}
 				next;
 			}
+			elsif ($line =~ /^q/i) {
+				while ($ix < $num) {
+					if (!defined $hunk[$ix]{USE}) {
+						$hunk[$ix]{USE} = 0;
+					}
+					$ix++;
+				}
+				$quit = 1;
+				next;
+			}
 			elsif ($line =~ m|^/(.*)|) {
 				my $regex = $1;
 				if ($1 eq "") {
@@ -1193,7 +1191,7 @@ sub patch_update_file {
 				$num = scalar @hunk;
 				next;
 			}
-			elsif ($line =~ /^e/) {
+			elsif ($other =~ /e/ && $line =~ /^e/) {
 				my $newhunk = edit_hunk_loop($head, \@hunk, $ix);
 				if (defined $newhunk) {
 					splice @hunk, $ix, 1, $newhunk;
@@ -1214,9 +1212,6 @@ sub patch_update_file {
 
 	my $n_lofs = 0;
 	my @result = ();
-	if ($mode->{USE}) {
-		push @result, @{$mode->{TEXT}};
-	}
 	for (@hunk) {
 		if ($_->{USE}) {
 			push @result, @{$_->{TEXT}};
@@ -1239,6 +1234,7 @@ sub patch_update_file {
 	}
 
 	print "\n";
+	return $quit;
 }
 
 sub diff_cmd {
diff --git a/git-am.sh b/git-am.sh
index d3390755fc..774383fb68 100755
--- a/git-am.sh
+++ b/git-am.sh
@@ -36,6 +36,13 @@ cd_to_toplevel
 git var GIT_COMMITTER_IDENT >/dev/null ||
 	die "You need to set your committer info first"
 
+if git rev-parse --verify -q HEAD >/dev/null
+then
+	HAS_HEAD=yes
+else
+	HAS_HEAD=
+fi
+
 sq () {
 	for sqarg
 	do
@@ -290,16 +297,26 @@ else
 		: >"$dotest/rebasing"
 	else
 		: >"$dotest/applying"
-		git update-ref ORIG_HEAD HEAD
+		if test -n "$HAS_HEAD"
+		then
+			git update-ref ORIG_HEAD HEAD
+		else
+			git update-ref -d ORIG_HEAD >/dev/null 2>&1
+		fi
 	fi
 fi
 
 case "$resolved" in
 '')
-	files=$(git diff-index --cached --name-only HEAD --) || exit
+	case "$HAS_HEAD" in
+	'')
+		files=$(git ls-files) ;;
+	?*)
+		files=$(git diff-index --cached --name-only HEAD --) ;;
+	esac || exit
 	if test "$files"
 	then
-		: >"$dotest/dirtyindex"
+		test -n "$HAS_HEAD" && : >"$dotest/dirtyindex"
 		die "Dirty index: cannot apply patches (dirty: $files)"
 	fi
 esac
@@ -541,18 +558,20 @@ do
 	fi
 
 	tree=$(git write-tree) &&
-	parent=$(git rev-parse --verify HEAD) &&
 	commit=$(
 		if test -n "$ignore_date"
 		then
 			GIT_AUTHOR_DATE=
 		fi
+		parent=$(git rev-parse --verify -q HEAD) ||
+		echo >&2 "applying to an empty history"
+
 		if test -n "$committer_date_is_author_date"
 		then
 			GIT_COMMITTER_DATE="$GIT_AUTHOR_DATE"
 			export GIT_COMMITTER_DATE
 		fi &&
-		git commit-tree $tree -p $parent <"$dotest/final-commit"
+		git commit-tree $tree ${parent:+-p $parent} <"$dotest/final-commit"
 	) &&
 	git update-ref -m "$GIT_REFLOG_ACTION: $FIRSTLINE" HEAD $commit $parent ||
 	stop_here $this
diff --git a/git-difftool--helper.sh b/git-difftool--helper.sh
new file mode 100755
index 0000000000..57e8e3256d
--- /dev/null
+++ b/git-difftool--helper.sh
@@ -0,0 +1,59 @@
+#!/bin/sh
+# git-difftool--helper is a GIT_EXTERNAL_DIFF-compatible diff tool launcher.
+# This script is typically launched by using the 'git difftool'
+# convenience command.
+#
+# Copyright (c) 2009 David Aguilar
+
+# Load common functions from git-mergetool--lib
+TOOL_MODE=diff
+. git-mergetool--lib
+
+# difftool.prompt controls the default prompt/no-prompt behavior
+# and is overridden with $GIT_DIFFTOOL*_PROMPT.
+should_prompt () {
+	prompt=$(git config --bool difftool.prompt || echo true)
+	if test "$prompt" = true; then
+		test -z "$GIT_DIFFTOOL_NO_PROMPT"
+	else
+		test -n "$GIT_DIFFTOOL_PROMPT"
+	fi
+}
+
+# Sets up shell variables and runs a merge tool
+launch_merge_tool () {
+	# Merged is the filename as it appears in the work tree
+	# Local is the contents of a/filename
+	# Remote is the contents of b/filename
+	# Custom merge tool commands might use $BASE so we provide it
+	MERGED="$1"
+	LOCAL="$2"
+	REMOTE="$3"
+	BASE="$1"
+
+	# $LOCAL and $REMOTE are temporary files so prompt
+	# the user with the real $MERGED name before launching $merge_tool.
+	if should_prompt; then
+		printf "\nViewing: '$MERGED'\n"
+		printf "Hit return to launch '%s': " "$merge_tool"
+		read ans
+	fi
+
+	# Run the appropriate merge tool command
+	run_merge_tool "$merge_tool"
+}
+
+# Allow GIT_DIFF_TOOL and GIT_MERGE_TOOL to provide default values
+test -n "$GIT_MERGE_TOOL" && merge_tool="$GIT_MERGE_TOOL"
+test -n "$GIT_DIFF_TOOL" && merge_tool="$GIT_DIFF_TOOL"
+
+if test -z "$merge_tool"; then
+	merge_tool="$(get_merge_tool)" || exit
+fi
+
+# Launch the merge tool on each path provided by 'git diff'
+while test $# -gt 6
+do
+	launch_merge_tool "$1" "$2" "$5"
+	shift 7
+done
diff --git a/contrib/difftool/git-difftool b/git-difftool.perl
similarity index 58%
rename from contrib/difftool/git-difftool
rename to git-difftool.perl
index 0deda3a0e4..948ff7f6fd 100755
--- a/contrib/difftool/git-difftool
+++ b/git-difftool.perl
@@ -2,9 +2,12 @@
 # Copyright (c) 2009 David Aguilar
 #
 # This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
-# git-difftool-helper script.  This script exports
-# GIT_EXTERNAL_DIFF and GIT_PAGER for use by git, and
-# GIT_DIFFTOOL_NO_PROMPT and GIT_DIFF_TOOL for use by git-difftool-helper.
+# git-difftool--helper script.
+#
+# This script exports GIT_EXTERNAL_DIFF and GIT_PAGER for use by git.
+# GIT_DIFFTOOL_NO_PROMPT, GIT_DIFFTOOL_PROMPT, and GIT_DIFF_TOOL
+# are exported for use by git-difftool--helper.
+#
 # Any arguments that are unknown to this script are forwarded to 'git diff'.
 
 use strict;
@@ -18,7 +21,7 @@ my $DIR = abs_path(dirname($0));
 sub usage
 {
 	print << 'USAGE';
-usage: git difftool [--tool=<tool>] [--no-prompt] ["git diff" options]
+usage: git difftool [--tool=<tool>] [-y|--no-prompt] ["git diff" options]
 USAGE
 	exit 1;
 }
@@ -27,13 +30,16 @@ sub setup_environment
 {
 	$ENV{PATH} = "$DIR:$ENV{PATH}";
 	$ENV{GIT_PAGER} = '';
-	$ENV{GIT_EXTERNAL_DIFF} = 'git-difftool-helper';
+	$ENV{GIT_EXTERNAL_DIFF} = 'git-difftool--helper';
 }
 
 sub exe
 {
 	my $exe = shift;
-	return defined $ENV{COMSPEC} ? "$exe.exe" : $exe;
+	if ($^O eq 'MSWin32' || $^O eq 'msys') {
+		return "$exe.exe";
+	}
+	return $exe;
 }
 
 sub generate_command
@@ -47,7 +53,7 @@ sub generate_command
 			$skip_next = 0;
 			next;
 		}
-		if ($arg eq '-t' or $arg eq '--tool') {
+		if ($arg eq '-t' || $arg eq '--tool') {
 			usage() if $#ARGV <= $idx;
 			$ENV{GIT_DIFF_TOOL} = $ARGV[$idx + 1];
 			$skip_next = 1;
@@ -57,11 +63,17 @@ sub generate_command
 			$ENV{GIT_DIFF_TOOL} = substr($arg, 7);
 			next;
 		}
-		if ($arg eq '--no-prompt') {
+		if ($arg eq '-y' || $arg eq '--no-prompt') {
 			$ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
+			delete $ENV{GIT_DIFFTOOL_PROMPT};
 			next;
 		}
-		if ($arg eq '-h' or $arg eq '--help') {
+		if ($arg eq '--prompt') {
+			$ENV{GIT_DIFFTOOL_PROMPT} = 'true';
+			delete $ENV{GIT_DIFFTOOL_NO_PROMPT};
+			next;
+		}
+		if ($arg eq '-h' || $arg eq '--help') {
 			usage();
 		}
 		push @command, $arg;
diff --git a/git-mergetool--lib.sh b/git-mergetool--lib.sh
new file mode 100644
index 0000000000..a16a2795d7
--- /dev/null
+++ b/git-mergetool--lib.sh
@@ -0,0 +1,385 @@
+# git-mergetool--lib is a library for common merge tool functions
+diff_mode() {
+	test "$TOOL_MODE" = diff
+}
+
+merge_mode() {
+	test "$TOOL_MODE" = merge
+}
+
+translate_merge_tool_path () {
+	case "$1" in
+	vimdiff)
+		echo vim
+		;;
+	gvimdiff)
+		echo gvim
+		;;
+	emerge)
+		echo emacs
+		;;
+	*)
+		echo "$1"
+		;;
+	esac
+}
+
+check_unchanged () {
+	if test "$MERGED" -nt "$BACKUP"; then
+		status=0
+	else
+		while true; do
+			echo "$MERGED seems unchanged."
+			printf "Was the merge successful? [y/n] "
+			read answer < /dev/tty
+			case "$answer" in
+			y*|Y*) status=0; break ;;
+			n*|N*) status=1; break ;;
+			esac
+		done
+	fi
+}
+
+valid_tool () {
+	case "$1" in
+	kdiff3 | tkdiff | xxdiff | meld | opendiff | \
+	emerge | vimdiff | gvimdiff | ecmerge | diffuse)
+		;; # happy
+	tortoisemerge)
+		if ! merge_mode; then
+			return 1
+		fi
+		;;
+	kompare)
+		if ! diff_mode; then
+			return 1
+		fi
+		;;
+	*)
+		if test -z "$(get_merge_tool_cmd "$1")"; then
+			return 1
+		fi
+		;;
+	esac
+}
+
+get_merge_tool_cmd () {
+	# Prints the custom command for a merge tool
+	if test -n "$1"; then
+		merge_tool="$1"
+	else
+		merge_tool="$(get_merge_tool)"
+	fi
+	if diff_mode; then
+		echo "$(git config difftool.$merge_tool.cmd ||
+		        git config mergetool.$merge_tool.cmd)"
+	else
+		echo "$(git config mergetool.$merge_tool.cmd)"
+	fi
+}
+
+run_merge_tool () {
+	merge_tool_path="$(get_merge_tool_path "$1")" || exit
+	base_present="$2"
+	status=0
+
+	case "$1" in
+	kdiff3)
+		if merge_mode; then
+			if $base_present; then
+				("$merge_tool_path" --auto \
+					--L1 "$MERGED (Base)" \
+					--L2 "$MERGED (Local)" \
+					--L3 "$MERGED (Remote)" \
+					-o "$MERGED" \
+					"$BASE" "$LOCAL" "$REMOTE" \
+				> /dev/null 2>&1)
+			else
+				("$merge_tool_path" --auto \
+					--L1 "$MERGED (Local)" \
+					--L2 "$MERGED (Remote)" \
+					-o "$MERGED" \
+					"$LOCAL" "$REMOTE" \
+				> /dev/null 2>&1)
+			fi
+			status=$?
+		else
+			("$merge_tool_path" --auto \
+				--L1 "$MERGED (A)" \
+				--L2 "$MERGED (B)" "$LOCAL" "$REMOTE" \
+			> /dev/null 2>&1)
+		fi
+		;;
+	kompare)
+		"$merge_tool_path" "$LOCAL" "$REMOTE"
+		;;
+	tkdiff)
+		if merge_mode; then
+			if $base_present; then
+				"$merge_tool_path" -a "$BASE" \
+					-o "$MERGED" "$LOCAL" "$REMOTE"
+			else
+				"$merge_tool_path" \
+					-o "$MERGED" "$LOCAL" "$REMOTE"
+			fi
+			status=$?
+		else
+			"$merge_tool_path" "$LOCAL" "$REMOTE"
+		fi
+		;;
+	meld)
+		if merge_mode; then
+			touch "$BACKUP"
+			"$merge_tool_path" "$LOCAL" "$MERGED" "$REMOTE"
+			check_unchanged
+		else
+			"$merge_tool_path" "$LOCAL" "$REMOTE"
+		fi
+		;;
+	diffuse)
+		if merge_mode; then
+			touch "$BACKUP"
+			if $base_present; then
+				"$merge_tool_path" \
+					"$LOCAL" "$MERGED" "$REMOTE" \
+					"$BASE" | cat
+			else
+				"$merge_tool_path" \
+					"$LOCAL" "$MERGED" "$REMOTE" | cat
+			fi
+			check_unchanged
+		else
+			"$merge_tool_path" "$LOCAL" "$REMOTE" | cat
+		fi
+		;;
+	vimdiff)
+		if merge_mode; then
+			touch "$BACKUP"
+			"$merge_tool_path" -d -c "wincmd l" \
+				"$LOCAL" "$MERGED" "$REMOTE"
+			check_unchanged
+		else
+			"$merge_tool_path" -d -c "wincmd l" \
+				"$LOCAL" "$REMOTE"
+		fi
+		;;
+	gvimdiff)
+		if merge_mode; then
+			touch "$BACKUP"
+			"$merge_tool_path" -d -c "wincmd l" -f \
+				"$LOCAL" "$MERGED" "$REMOTE"
+			check_unchanged
+		else
+			"$merge_tool_path" -d -c "wincmd l" -f \
+				"$LOCAL" "$REMOTE"
+		fi
+		;;
+	xxdiff)
+		if merge_mode; then
+			touch "$BACKUP"
+			if $base_present; then
+				"$merge_tool_path" -X --show-merged-pane \
+					-R 'Accel.SaveAsMerged: "Ctrl-S"' \
+					-R 'Accel.Search: "Ctrl+F"' \
+					-R 'Accel.SearchForward: "Ctrl-G"' \
+					--merged-file "$MERGED" \
+					"$LOCAL" "$BASE" "$REMOTE"
+			else
+				"$merge_tool_path" -X $extra \
+					-R 'Accel.SaveAsMerged: "Ctrl-S"' \
+					-R 'Accel.Search: "Ctrl+F"' \
+					-R 'Accel.SearchForward: "Ctrl-G"' \
+					--merged-file "$MERGED" \
+					"$LOCAL" "$REMOTE"
+			fi
+			check_unchanged
+		else
+			"$merge_tool_path" \
+				-R 'Accel.Search: "Ctrl+F"' \
+				-R 'Accel.SearchForward: "Ctrl-G"' \
+				"$LOCAL" "$REMOTE"
+		fi
+		;;
+	opendiff)
+		if merge_mode; then
+			touch "$BACKUP"
+			if $base_present; then
+				"$merge_tool_path" "$LOCAL" "$REMOTE" \
+					-ancestor "$BASE" \
+					-merge "$MERGED" | cat
+			else
+				"$merge_tool_path" "$LOCAL" "$REMOTE" \
+					-merge "$MERGED" | cat
+			fi
+			check_unchanged
+		else
+			"$merge_tool_path" "$LOCAL" "$REMOTE" | cat
+		fi
+		;;
+	ecmerge)
+		if merge_mode; then
+			touch "$BACKUP"
+			if $base_present; then
+				"$merge_tool_path" "$BASE" "$LOCAL" "$REMOTE" \
+					--default --mode=merge3 --to="$MERGED"
+			else
+				"$merge_tool_path" "$LOCAL" "$REMOTE" \
+					--default --mode=merge2 --to="$MERGED"
+			fi
+			check_unchanged
+		else
+			"$merge_tool_path" "$LOCAL" "$REMOTE" \
+				--default --mode=merge2 --to="$MERGED"
+		fi
+		;;
+	emerge)
+		if merge_mode; then
+			if $base_present; then
+				"$merge_tool_path" \
+					-f emerge-files-with-ancestor-command \
+					"$LOCAL" "$REMOTE" "$BASE" \
+					"$(basename "$MERGED")"
+			else
+				"$merge_tool_path" \
+					-f emerge-files-command \
+					"$LOCAL" "$REMOTE" \
+					"$(basename "$MERGED")"
+			fi
+			status=$?
+		else
+			"$merge_tool_path" -f emerge-files-command \
+				"$LOCAL" "$REMOTE" "$(basename "$MERGED")"
+		fi
+		;;
+	tortoisemerge)
+		if $base_present; then
+			touch "$BACKUP"
+			"$merge_tool_path" \
+				-base:"$BASE" -mine:"$LOCAL" \
+				-theirs:"$REMOTE" -merged:"$MERGED"
+			check_unchanged
+		else
+			echo "TortoiseMerge cannot be used without a base" 1>&2
+			status=1
+		fi
+		;;
+	*)
+		merge_tool_cmd="$(get_merge_tool_cmd "$1")"
+		if test -z "$merge_tool_cmd"; then
+			if merge_mode; then
+				status=1
+			fi
+			break
+		fi
+		if merge_mode; then
+			trust_exit_code="$(git config --bool \
+				mergetool."$1".trustExitCode || echo false)"
+			if test "$trust_exit_code" = "false"; then
+				touch "$BACKUP"
+				( eval $merge_tool_cmd )
+				check_unchanged
+			else
+				( eval $merge_tool_cmd )
+				status=$?
+			fi
+		else
+			( eval $merge_tool_cmd )
+		fi
+		;;
+	esac
+	return $status
+}
+
+guess_merge_tool () {
+	if merge_mode; then
+		tools="tortoisemerge"
+	else
+		tools="kompare"
+	fi
+	if test -n "$DISPLAY"; then
+		if test -n "$GNOME_DESKTOP_SESSION_ID" ; then
+			tools="meld opendiff kdiff3 tkdiff xxdiff $tools"
+		else
+			tools="opendiff kdiff3 tkdiff xxdiff meld $tools"
+		fi
+		tools="$tools gvimdiff diffuse ecmerge"
+	fi
+	if echo "${VISUAL:-$EDITOR}" | grep emacs > /dev/null 2>&1; then
+		# $EDITOR is emacs so add emerge as a candidate
+		tools="$tools emerge vimdiff"
+	elif echo "${VISUAL:-$EDITOR}" | grep vim > /dev/null 2>&1; then
+		# $EDITOR is vim so add vimdiff as a candidate
+		tools="$tools vimdiff emerge"
+	else
+		tools="$tools emerge vimdiff"
+	fi
+	echo >&2 "merge tool candidates: $tools"
+
+	# Loop over each candidate and stop when a valid merge tool is found.
+	for i in $tools
+	do
+		merge_tool_path="$(translate_merge_tool_path "$i")"
+		if type "$merge_tool_path" > /dev/null 2>&1; then
+			echo "$i"
+			return 0
+		fi
+	done
+
+	echo >&2 "No known merge resolution program available."
+	return 1
+}
+
+get_configured_merge_tool () {
+	# Diff mode first tries diff.tool and falls back to merge.tool.
+	# Merge mode only checks merge.tool
+	if diff_mode; then
+		merge_tool=$(git config diff.tool || git config merge.tool)
+	else
+		merge_tool=$(git config merge.tool)
+	fi
+	if test -n "$merge_tool" && ! valid_tool "$merge_tool"; then
+		echo >&2 "git config option $TOOL_MODE.tool set to unknown tool: $merge_tool"
+		echo >&2 "Resetting to default..."
+		return 1
+	fi
+	echo "$merge_tool"
+}
+
+get_merge_tool_path () {
+	# A merge tool has been set, so verify that it's valid.
+	if test -n "$1"; then
+		merge_tool="$1"
+	else
+		merge_tool="$(get_merge_tool)"
+	fi
+	if ! valid_tool "$merge_tool"; then
+		echo >&2 "Unknown merge tool $merge_tool"
+		exit 1
+	fi
+	if diff_mode; then
+		merge_tool_path=$(git config difftool."$merge_tool".path ||
+		                  git config mergetool."$merge_tool".path)
+	else
+		merge_tool_path=$(git config mergetool."$merge_tool".path)
+	fi
+	if test -z "$merge_tool_path"; then
+		merge_tool_path="$(translate_merge_tool_path "$merge_tool")"
+	fi
+	if test -z "$(get_merge_tool_cmd "$merge_tool")" &&
+	! type "$merge_tool_path" > /dev/null 2>&1; then
+		echo >&2 "The $TOOL_MODE tool $merge_tool is not available as"\
+		         "'$merge_tool_path'"
+		exit 1
+	fi
+	echo "$merge_tool_path"
+}
+
+get_merge_tool () {
+	# Check if a merge tool has been configured
+	merge_tool=$(get_configured_merge_tool)
+	# Try to guess an appropriate merge tool if no tool has been set.
+	if test -z "$merge_tool"; then
+		merge_tool="$(guess_merge_tool)" || exit
+	fi
+	echo "$merge_tool"
+}
diff --git a/git-mergetool.sh b/git-mergetool.sh
index 87fa88af55..b52a7410bc 100755
--- a/git-mergetool.sh
+++ b/git-mergetool.sh
@@ -11,7 +11,9 @@
 USAGE='[--tool=tool] [-y|--no-prompt|--prompt] [file to merge] ...'
 SUBDIRECTORY_OK=Yes
 OPTIONS_SPEC=
+TOOL_MODE=merge
 . git-sh-setup
+. git-mergetool--lib
 require_work_tree
 
 # Returns true if the mode reflects a symlink
@@ -110,22 +112,6 @@ resolve_deleted_merge () {
 	done
 }
 
-check_unchanged () {
-    if test "$MERGED" -nt "$BACKUP" ; then
-	status=0;
-    else
-	while true; do
-	    echo "$MERGED seems unchanged."
-	    printf "Was the merge successful? [y/n] "
-	    read answer < /dev/tty
-	    case "$answer" in
-		y*|Y*) status=0; break ;;
-		n*|N*) status=1; break ;;
-	    esac
-	done
-    fi
-}
-
 checkout_staged_file () {
     tmpfile=$(expr "$(git checkout-index --temp --stage="$1" "$2")" : '\([^	]*\)	')
 
@@ -137,7 +123,7 @@ checkout_staged_file () {
 merge_file () {
     MERGED="$1"
 
-    f=`git ls-files -u -- "$MERGED"`
+    f=$(git ls-files -u -- "$MERGED")
     if test -z "$f" ; then
 	if test ! -f "$MERGED" ; then
 	    echo "$MERGED: file not found"
@@ -156,9 +142,9 @@ merge_file () {
     mv -- "$MERGED" "$BACKUP"
     cp -- "$BACKUP" "$MERGED"
 
-    base_mode=`git ls-files -u -- "$MERGED" | awk '{if ($3==1) print $1;}'`
-    local_mode=`git ls-files -u -- "$MERGED" | awk '{if ($3==2) print $1;}'`
-    remote_mode=`git ls-files -u -- "$MERGED" | awk '{if ($3==3) print $1;}'`
+    base_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==1) print $1;}')
+    local_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==2) print $1;}')
+    remote_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==3) print $1;}')
 
     base_present   && checkout_staged_file 1 "$MERGED" "$BASE"
     local_present  && checkout_staged_file 2 "$MERGED" "$LOCAL"
@@ -188,97 +174,13 @@ merge_file () {
 	read ans
     fi
 
-    case "$merge_tool" in
-	kdiff3)
-	    if base_present ; then
-		("$merge_tool_path" --auto --L1 "$MERGED (Base)" --L2 "$MERGED (Local)" --L3 "$MERGED (Remote)" \
-		    -o "$MERGED" "$BASE" "$LOCAL" "$REMOTE" > /dev/null 2>&1)
-	    else
-		("$merge_tool_path" --auto --L1 "$MERGED (Local)" --L2 "$MERGED (Remote)" \
-		    -o "$MERGED" "$LOCAL" "$REMOTE" > /dev/null 2>&1)
-	    fi
-	    status=$?
-	    ;;
-	tkdiff)
-	    if base_present ; then
-		"$merge_tool_path" -a "$BASE" -o "$MERGED" "$LOCAL" "$REMOTE"
-	    else
-		"$merge_tool_path" -o "$MERGED" "$LOCAL" "$REMOTE"
-	    fi
-	    status=$?
-	    ;;
-	meld)
-	    touch "$BACKUP"
-	    "$merge_tool_path" "$LOCAL" "$MERGED" "$REMOTE"
-	    check_unchanged
-	    ;;
-	vimdiff)
-	    touch "$BACKUP"
-	    "$merge_tool_path" -c "wincmd l" "$LOCAL" "$MERGED" "$REMOTE"
-	    check_unchanged
-	    ;;
-	gvimdiff)
-	    touch "$BACKUP"
-	    "$merge_tool_path" -c "wincmd l" -f "$LOCAL" "$MERGED" "$REMOTE"
-	    check_unchanged
-	    ;;
-	xxdiff)
-	    touch "$BACKUP"
-	    if base_present ; then
-		"$merge_tool_path" -X --show-merged-pane \
-		    -R 'Accel.SaveAsMerged: "Ctrl-S"' \
-		    -R 'Accel.Search: "Ctrl+F"' \
-		    -R 'Accel.SearchForward: "Ctrl-G"' \
-		    --merged-file "$MERGED" "$LOCAL" "$BASE" "$REMOTE"
-	    else
-		"$merge_tool_path" -X --show-merged-pane \
-		    -R 'Accel.SaveAsMerged: "Ctrl-S"' \
-		    -R 'Accel.Search: "Ctrl+F"' \
-		    -R 'Accel.SearchForward: "Ctrl-G"' \
-		    --merged-file "$MERGED" "$LOCAL" "$REMOTE"
-	    fi
-	    check_unchanged
-	    ;;
-	opendiff)
-	    touch "$BACKUP"
-	    if base_present; then
-		"$merge_tool_path" "$LOCAL" "$REMOTE" -ancestor "$BASE" -merge "$MERGED" | cat
-	    else
-		"$merge_tool_path" "$LOCAL" "$REMOTE" -merge "$MERGED" | cat
-	    fi
-	    check_unchanged
-	    ;;
-	ecmerge)
-	    touch "$BACKUP"
-	    if base_present; then
-		"$merge_tool_path" "$BASE" "$LOCAL" "$REMOTE" --default --mode=merge3 --to="$MERGED"
-	    else
-		"$merge_tool_path" "$LOCAL" "$REMOTE" --default --mode=merge2 --to="$MERGED"
-	    fi
-	    check_unchanged
-	    ;;
-	emerge)
-	    if base_present ; then
-		"$merge_tool_path" -f emerge-files-with-ancestor-command "$LOCAL" "$REMOTE" "$BASE" "$(basename "$MERGED")"
-	    else
-		"$merge_tool_path" -f emerge-files-command "$LOCAL" "$REMOTE" "$(basename "$MERGED")"
-	    fi
-	    status=$?
-	    ;;
-	*)
-	    if test -n "$merge_tool_cmd"; then
-		if test "$merge_tool_trust_exit_code" = "false"; then
-		    touch "$BACKUP"
-		    ( eval $merge_tool_cmd )
-		    check_unchanged
-		else
-		    ( eval $merge_tool_cmd )
-		    status=$?
-		fi
-	    fi
-	    ;;
-    esac
-    if test "$status" -ne 0; then
+    if base_present; then
+	    present=true
+    else
+	    present=false
+    fi
+
+    if ! run_merge_tool "$merge_tool" "$present"; then
 	echo "merge of $MERGED failed" 1>&2
 	mv -- "$BACKUP" "$MERGED"
 
@@ -308,7 +210,7 @@ do
 	-t|--tool*)
 	    case "$#,$1" in
 		*,*=*)
-		    merge_tool=`expr "z$1" : 'z-[^=]*=\(.*\)'`
+		    merge_tool=$(expr "z$1" : 'z-[^=]*=\(.*\)')
 		    ;;
 		1,*)
 		    usage ;;
@@ -337,38 +239,6 @@ do
     shift
 done
 
-valid_custom_tool()
-{
-    merge_tool_cmd="$(git config mergetool.$1.cmd)"
-    test -n "$merge_tool_cmd"
-}
-
-valid_tool() {
-	case "$1" in
-		kdiff3 | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff | ecmerge)
-			;; # happy
-		*)
-			if ! valid_custom_tool "$1"; then
-				return 1
-			fi
-			;;
-	esac
-}
-
-init_merge_tool_path() {
-	merge_tool_path=`git config mergetool.$1.path`
-	if test -z "$merge_tool_path" ; then
-		case "$1" in
-			emerge)
-				merge_tool_path=emacs
-				;;
-			*)
-				merge_tool_path=$1
-				;;
-		esac
-	fi
-}
-
 prompt_after_failed_merge() {
     while true; do
 	printf "Continue merging other unresolved paths (y/n) ? "
@@ -387,67 +257,16 @@ prompt_after_failed_merge() {
 }
 
 if test -z "$merge_tool"; then
-    merge_tool=`git config merge.tool`
-    if test -n "$merge_tool" && ! valid_tool "$merge_tool"; then
-	    echo >&2 "git config option merge.tool set to unknown tool: $merge_tool"
-	    echo >&2 "Resetting to default..."
-	    unset merge_tool
-    fi
-fi
-
-if test -z "$merge_tool" ; then
-    if test -n "$DISPLAY"; then
-        if test -n "$GNOME_DESKTOP_SESSION_ID" ; then
-            merge_tool_candidates="meld kdiff3 tkdiff xxdiff gvimdiff"
-        else
-            merge_tool_candidates="kdiff3 tkdiff xxdiff meld gvimdiff"
-        fi
-    fi
-    if echo "${VISUAL:-$EDITOR}" | grep 'emacs' > /dev/null 2>&1; then
-        merge_tool_candidates="$merge_tool_candidates emerge opendiff vimdiff"
-    elif echo "${VISUAL:-$EDITOR}" | grep 'vim' > /dev/null 2>&1; then
-        merge_tool_candidates="$merge_tool_candidates vimdiff opendiff emerge"
-    else
-        merge_tool_candidates="$merge_tool_candidates opendiff emerge vimdiff"
-    fi
-    echo "merge tool candidates: $merge_tool_candidates"
-    for i in $merge_tool_candidates; do
-        init_merge_tool_path $i
-        if type "$merge_tool_path" > /dev/null 2>&1; then
-            merge_tool=$i
-            break
-        fi
-    done
-    if test -z "$merge_tool" ; then
-	echo "No known merge resolution program available."
-	exit 1
-    fi
-else
-    if ! valid_tool "$merge_tool"; then
-        echo >&2 "Unknown merge_tool $merge_tool"
-        exit 1
-    fi
-
-    init_merge_tool_path "$merge_tool"
-
-    merge_keep_backup="$(git config --bool merge.keepBackup || echo true)"
-    merge_keep_temporaries="$(git config --bool mergetool.keepTemporaries || echo false)"
-
-    if test -z "$merge_tool_cmd" && ! type "$merge_tool_path" > /dev/null 2>&1; then
-        echo "The merge tool $merge_tool is not available as '$merge_tool_path'"
-        exit 1
-    fi
-
-    if ! test -z "$merge_tool_cmd"; then
-        merge_tool_trust_exit_code="$(git config --bool mergetool.$merge_tool.trustExitCode || echo false)"
-    fi
+    merge_tool=$(get_merge_tool "$merge_tool") || exit
 fi
+merge_keep_backup="$(git config --bool mergetool.keepBackup || echo true)"
+merge_keep_temporaries="$(git config --bool mergetool.keepTemporaries || echo false)"
 
 last_status=0
 rollup_status=0
 
 if test $# -eq 0 ; then
-    files=`git ls-files -u | sed -e 's/^[^	]*	//' | sort -u`
+    files=$(git ls-files -u | sed -e 's/^[^	]*	//' | sort -u)
     if test -z "$files" ; then
 	echo "No files need merging"
 	exit 0
diff --git a/graph.c b/graph.c
index 162a516ee1..d4571cf31d 100644
--- a/graph.c
+++ b/graph.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "commit.h"
+#include "color.h"
 #include "graph.h"
 #include "diff.h"
 #include "revision.h"
@@ -43,10 +44,6 @@ static void graph_show_strbuf(struct git_graph *graph, struct strbuf const *sb);
 
 /*
  * TODO:
- * - Add colors to the graph.
- *   Pick a color for each column, and print all characters
- *   in that column with the specified color.
- *
  * - Limit the number of columns, similar to the way gitk does.
  *   If we reach more than a specified number of columns, omit
  *   sections of some columns.
@@ -72,9 +69,10 @@ struct column {
 	 */
 	struct commit *commit;
 	/*
-	 * XXX: Once we add support for colors, struct column could also
-	 * contain the color of its branch line.
+	 * The color to (optionally) print this column in.  This is an
+	 * index into column_colors.
 	 */
+	unsigned short color;
 };
 
 enum graph_state {
@@ -86,6 +84,41 @@ enum graph_state {
 	GRAPH_COLLAPSING
 };
 
+/*
+ * The list of available column colors.
+ */
+static char column_colors[][COLOR_MAXLEN] = {
+	GIT_COLOR_RED,
+	GIT_COLOR_GREEN,
+	GIT_COLOR_YELLOW,
+	GIT_COLOR_BLUE,
+	GIT_COLOR_MAGENTA,
+	GIT_COLOR_CYAN,
+	GIT_COLOR_BOLD GIT_COLOR_RED,
+	GIT_COLOR_BOLD GIT_COLOR_GREEN,
+	GIT_COLOR_BOLD GIT_COLOR_YELLOW,
+	GIT_COLOR_BOLD GIT_COLOR_BLUE,
+	GIT_COLOR_BOLD GIT_COLOR_MAGENTA,
+	GIT_COLOR_BOLD GIT_COLOR_CYAN,
+};
+
+#define COLUMN_COLORS_MAX (ARRAY_SIZE(column_colors))
+
+static const char *column_get_color_code(const struct column *c)
+{
+	return column_colors[c->color];
+}
+
+static void strbuf_write_column(struct strbuf *sb, const struct column *c,
+				char col_char)
+{
+	if (c->color < COLUMN_COLORS_MAX)
+		strbuf_addstr(sb, column_get_color_code(c));
+	strbuf_addch(sb, col_char);
+	if (c->color < COLUMN_COLORS_MAX)
+		strbuf_addstr(sb, GIT_COLOR_RESET);
+}
+
 struct git_graph {
 	/*
 	 * The commit currently being processed
@@ -185,6 +218,11 @@ struct git_graph {
 	 * temporary array each time we have to output a collapsing line.
 	 */
 	int *new_mapping;
+	/*
+	 * The current default column color being used.  This is
+	 * stored as an index into the array column_colors.
+	 */
+	unsigned short default_column_color;
 };
 
 struct git_graph *graph_init(struct rev_info *opt)
@@ -201,6 +239,7 @@ struct git_graph *graph_init(struct rev_info *opt)
 	graph->num_columns = 0;
 	graph->num_new_columns = 0;
 	graph->mapping_size = 0;
+	graph->default_column_color = 0;
 
 	/*
 	 * Allocate a reasonably large default number of columns
@@ -312,6 +351,33 @@ static struct commit_list *first_interesting_parent(struct git_graph *graph)
 	return next_interesting_parent(graph, parents);
 }
 
+static unsigned short graph_get_current_column_color(const struct git_graph *graph)
+{
+	if (!DIFF_OPT_TST(&graph->revs->diffopt, COLOR_DIFF))
+		return COLUMN_COLORS_MAX;
+	return graph->default_column_color;
+}
+
+/*
+ * Update the graph's default column color.
+ */
+static void graph_increment_column_color(struct git_graph *graph)
+{
+	graph->default_column_color = (graph->default_column_color + 1) %
+		COLUMN_COLORS_MAX;
+}
+
+static unsigned short graph_find_commit_color(const struct git_graph *graph,
+					      const struct commit *commit)
+{
+	int i;
+	for (i = 0; i < graph->num_columns; i++) {
+		if (graph->columns[i].commit == commit)
+			return graph->columns[i].color;
+	}
+	return graph_get_current_column_color(graph);
+}
+
 static void graph_insert_into_new_columns(struct git_graph *graph,
 					  struct commit *commit,
 					  int *mapping_index)
@@ -334,6 +400,7 @@ static void graph_insert_into_new_columns(struct git_graph *graph,
 	 * This commit isn't already in new_columns.  Add it.
 	 */
 	graph->new_columns[graph->num_new_columns].commit = commit;
+	graph->new_columns[graph->num_new_columns].color = graph_find_commit_color(graph, commit);
 	graph->mapping[*mapping_index] = graph->num_new_columns;
 	*mapping_index += 2;
 	graph->num_new_columns++;
@@ -445,6 +512,12 @@ static void graph_update_columns(struct git_graph *graph)
 			for (parent = first_interesting_parent(graph);
 			     parent;
 			     parent = next_interesting_parent(graph, parent)) {
+				/*
+				 * If this is a merge increment the current
+				 * color.
+				 */
+				if (graph->num_parents > 1)
+					graph_increment_column_color(graph);
 				graph_insert_into_new_columns(graph,
 							      parent->item,
 							      &mapping_idx);
@@ -560,7 +633,8 @@ static int graph_is_mapping_correct(struct git_graph *graph)
 	return 1;
 }
 
-static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb)
+static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb,
+				   int chars_written)
 {
 	/*
 	 * Add additional spaces to the end of the strbuf, so that all
@@ -570,10 +644,10 @@ static void graph_pad_horizontally(struct git_graph *graph, struct strbuf *sb)
 	 * aligned for the entire commit.
 	 */
 	int extra;
-	if (sb->len >= graph->width)
+	if (chars_written >= graph->width)
 		return;
 
-	extra = graph->width - sb->len;
+	extra = graph->width - chars_written;
 	strbuf_addf(sb, "%*s", (int) extra, "");
 }
 
@@ -596,10 +670,11 @@ static void graph_output_padding_line(struct git_graph *graph,
 	 * Output a padding row, that leaves all branch lines unchanged
 	 */
 	for (i = 0; i < graph->num_new_columns; i++) {
-		strbuf_addstr(sb, "| ");
+		strbuf_write_column(sb, &graph->new_columns[i], '|');
+		strbuf_addch(sb, ' ');
 	}
 
-	graph_pad_horizontally(graph, sb);
+	graph_pad_horizontally(graph, sb, graph->num_new_columns * 2);
 }
 
 static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
@@ -609,7 +684,7 @@ static void graph_output_skip_line(struct git_graph *graph, struct strbuf *sb)
 	 * of the graph is missing.
 	 */
 	strbuf_addstr(sb, "...");
-	graph_pad_horizontally(graph, sb);
+	graph_pad_horizontally(graph, sb, 3);
 
 	if (graph->num_parents >= 3 &&
 	    graph->commit_index < (graph->num_columns - 1))
@@ -623,6 +698,7 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 {
 	int num_expansion_rows;
 	int i, seen_this;
+	int chars_written;
 
 	/*
 	 * This function formats a row that increases the space around a commit
@@ -645,11 +721,14 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 	 * Output the row
 	 */
 	seen_this = 0;
+	chars_written = 0;
 	for (i = 0; i < graph->num_columns; i++) {
 		struct column *col = &graph->columns[i];
 		if (col->commit == graph->commit) {
 			seen_this = 1;
-			strbuf_addf(sb, "| %*s", graph->expansion_row, "");
+			strbuf_write_column(sb, col, '|');
+			strbuf_addf(sb, " %*s", graph->expansion_row, "");
+			chars_written += 2 + graph->expansion_row;
 		} else if (seen_this && (graph->expansion_row == 0)) {
 			/*
 			 * This is the first line of the pre-commit output.
@@ -662,17 +741,22 @@ static void graph_output_pre_commit_line(struct git_graph *graph,
 			 */
 			if (graph->prev_state == GRAPH_POST_MERGE &&
 			    graph->prev_commit_index < i)
-				strbuf_addstr(sb, "\\ ");
+				strbuf_write_column(sb, col, '\\');
 			else
-				strbuf_addstr(sb, "| ");
+				strbuf_write_column(sb, col, '|');
+			chars_written++;
 		} else if (seen_this && (graph->expansion_row > 0)) {
-			strbuf_addstr(sb, "\\ ");
+			strbuf_write_column(sb, col, '\\');
+			chars_written++;
 		} else {
-			strbuf_addstr(sb, "| ");
+			strbuf_write_column(sb, col, '|');
+			chars_written++;
 		}
+		strbuf_addch(sb, ' ');
+		chars_written++;
 	}
 
-	graph_pad_horizontally(graph, sb);
+	graph_pad_horizontally(graph, sb, chars_written);
 
 	/*
 	 * Increment graph->expansion_row,
@@ -714,10 +798,34 @@ static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
 	strbuf_addch(sb, '*');
 }
 
+/*
+ * Draw an octopus merge and return the number of characters written.
+ */
+static int graph_draw_octopus_merge(struct git_graph *graph,
+				    struct strbuf *sb)
+{
+	/*
+	 * Here dashless_commits represents the number of parents
+	 * which don't need to have dashes (because their edges fit
+	 * neatly under the commit).
+	 */
+	const int dashless_commits = 2;
+	int col_num, i;
+	int num_dashes =
+		((graph->num_parents - dashless_commits) * 2) - 1;
+	for (i = 0; i < num_dashes; i++) {
+		col_num = (i / 2) + dashless_commits;
+		strbuf_write_column(sb, &graph->new_columns[col_num], '-');
+	}
+	col_num = (i / 2) + dashless_commits;
+	strbuf_write_column(sb, &graph->new_columns[col_num], '.');
+	return num_dashes + 1;
+}
+
 static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 {
 	int seen_this = 0;
-	int i, j;
+	int i, chars_written;
 
 	/*
 	 * Output the row containing this commit
@@ -727,7 +835,9 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 	 * children that we have already processed.)
 	 */
 	seen_this = 0;
+	chars_written = 0;
 	for (i = 0; i <= graph->num_columns; i++) {
+		struct column *col = &graph->columns[i];
 		struct commit *col_commit;
 		if (i == graph->num_columns) {
 			if (seen_this)
@@ -740,18 +850,14 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 		if (col_commit == graph->commit) {
 			seen_this = 1;
 			graph_output_commit_char(graph, sb);
+			chars_written++;
 
-			if (graph->num_parents < 3)
-				strbuf_addch(sb, ' ');
-			else {
-				int num_dashes =
-					((graph->num_parents - 2) * 2) - 1;
-				for (j = 0; j < num_dashes; j++)
-					strbuf_addch(sb, '-');
-				strbuf_addstr(sb, ". ");
-			}
+			if (graph->num_parents > 3)
+				chars_written += graph_draw_octopus_merge(graph,
+									  sb);
 		} else if (seen_this && (graph->num_parents > 2)) {
-			strbuf_addstr(sb, "\\ ");
+			strbuf_write_column(sb, col, '\\');
+			chars_written++;
 		} else if (seen_this && (graph->num_parents == 2)) {
 			/*
 			 * This is a 2-way merge commit.
@@ -768,15 +874,19 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 			 */
 			if (graph->prev_state == GRAPH_POST_MERGE &&
 			    graph->prev_commit_index < i)
-				strbuf_addstr(sb, "\\ ");
+				strbuf_write_column(sb, col, '\\');
 			else
-				strbuf_addstr(sb, "| ");
+				strbuf_write_column(sb, col, '|');
+			chars_written++;
 		} else {
-			strbuf_addstr(sb, "| ");
+			strbuf_write_column(sb, col, '|');
+			chars_written++;
 		}
+		strbuf_addch(sb, ' ');
+		chars_written++;
 	}
 
-	graph_pad_horizontally(graph, sb);
+	graph_pad_horizontally(graph, sb, chars_written);
 
 	/*
 	 * Update graph->state
@@ -789,37 +899,75 @@ static void graph_output_commit_line(struct git_graph *graph, struct strbuf *sb)
 		graph_update_state(graph, GRAPH_COLLAPSING);
 }
 
+static struct column *find_new_column_by_commit(struct git_graph *graph,
+						struct commit *commit)
+{
+	int i;
+	for (i = 0; i < graph->num_new_columns; i++) {
+		if (graph->new_columns[i].commit == commit)
+			return &graph->new_columns[i];
+	}
+	return 0;
+}
+
 static void graph_output_post_merge_line(struct git_graph *graph, struct strbuf *sb)
 {
 	int seen_this = 0;
-	int i, j;
+	int i, j, chars_written;
 
 	/*
 	 * Output the post-merge row
 	 */
+	chars_written = 0;
 	for (i = 0; i <= graph->num_columns; i++) {
+		struct column *col = &graph->columns[i];
 		struct commit *col_commit;
 		if (i == graph->num_columns) {
 			if (seen_this)
 				break;
 			col_commit = graph->commit;
 		} else {
-			col_commit = graph->columns[i].commit;
+			col_commit = col->commit;
 		}
 
 		if (col_commit == graph->commit) {
+			/*
+			 * Since the current commit is a merge find
+			 * the columns for the parent commits in
+			 * new_columns and use those to format the
+			 * edges.
+			 */
+			struct commit_list *parents = NULL;
+			struct column *par_column;
 			seen_this = 1;
-			strbuf_addch(sb, '|');
-			for (j = 0; j < graph->num_parents - 1; j++)
-				strbuf_addstr(sb, "\\ ");
+			parents = first_interesting_parent(graph);
+			assert(parents);
+			par_column = find_new_column_by_commit(graph, parents->item);
+			assert(par_column);
+
+			strbuf_write_column(sb, par_column, '|');
+			chars_written++;
+			for (j = 0; j < graph->num_parents - 1; j++) {
+				parents = next_interesting_parent(graph, parents);
+				assert(parents);
+				par_column = find_new_column_by_commit(graph, parents->item);
+				assert(par_column);
+				strbuf_write_column(sb, par_column, '\\');
+				strbuf_addch(sb, ' ');
+			}
+			chars_written += j * 2;
 		} else if (seen_this) {
-			strbuf_addstr(sb, "\\ ");
+			strbuf_write_column(sb, col, '\\');
+			strbuf_addch(sb, ' ');
+			chars_written += 2;
 		} else {
-			strbuf_addstr(sb, "| ");
+			strbuf_write_column(sb, col, '|');
+			strbuf_addch(sb, ' ');
+			chars_written += 2;
 		}
 	}
 
-	graph_pad_horizontally(graph, sb);
+	graph_pad_horizontally(graph, sb, chars_written);
 
 	/*
 	 * Update graph->state
@@ -912,12 +1060,12 @@ static void graph_output_collapsing_line(struct git_graph *graph, struct strbuf
 		if (target < 0)
 			strbuf_addch(sb, ' ');
 		else if (target * 2 == i)
-			strbuf_addch(sb, '|');
+			strbuf_write_column(sb, &graph->new_columns[target], '|');
 		else
-			strbuf_addch(sb, '/');
+			strbuf_write_column(sb, &graph->new_columns[target], '/');
 	}
 
-	graph_pad_horizontally(graph, sb);
+	graph_pad_horizontally(graph, sb, graph->mapping_size);
 
 	/*
 	 * Swap mapping and new_mapping
@@ -979,9 +1127,10 @@ static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
 	 * children that we have already processed.)
 	 */
 	for (i = 0; i < graph->num_columns; i++) {
-		struct commit *col_commit = graph->columns[i].commit;
+		struct column *col = &graph->columns[i];
+		struct commit *col_commit = col->commit;
 		if (col_commit == graph->commit) {
-			strbuf_addch(sb, '|');
+			strbuf_write_column(sb, col, '|');
 
 			if (graph->num_parents < 3)
 				strbuf_addch(sb, ' ');
@@ -991,11 +1140,12 @@ static void graph_padding_line(struct git_graph *graph, struct strbuf *sb)
 					strbuf_addch(sb, ' ');
 			}
 		} else {
-			strbuf_addstr(sb, "| ");
+			strbuf_write_column(sb, col, '|');
+			strbuf_addch(sb, ' ');
 		}
 	}
 
-	graph_pad_horizontally(graph, sb);
+	graph_pad_horizontally(graph, sb, graph->num_columns);
 
 	/*
 	 * Update graph->prev_state since we have output a padding line
diff --git a/list-objects.c b/list-objects.c
index 433394a107..8953548c07 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -10,7 +10,7 @@
 
 static void process_blob(struct rev_info *revs,
 			 struct blob *blob,
-			 struct object_array *p,
+			 show_object_fn show,
 			 struct name_path *path,
 			 const char *name)
 {
@@ -23,7 +23,7 @@ static void process_blob(struct rev_info *revs,
 	if (obj->flags & (UNINTERESTING | SEEN))
 		return;
 	obj->flags |= SEEN;
-	add_object(obj, p, path, name);
+	show(obj, path, name);
 }
 
 /*
@@ -50,7 +50,7 @@ static void process_blob(struct rev_info *revs,
  */
 static void process_gitlink(struct rev_info *revs,
 			    const unsigned char *sha1,
-			    struct object_array *p,
+			    show_object_fn show,
 			    struct name_path *path,
 			    const char *name)
 {
@@ -59,7 +59,7 @@ static void process_gitlink(struct rev_info *revs,
 
 static void process_tree(struct rev_info *revs,
 			 struct tree *tree,
-			 struct object_array *p,
+			 show_object_fn show,
 			 struct name_path *path,
 			 const char *name)
 {
@@ -77,7 +77,7 @@ static void process_tree(struct rev_info *revs,
 	if (parse_tree(tree) < 0)
 		die("bad tree object %s", sha1_to_hex(obj->sha1));
 	obj->flags |= SEEN;
-	add_object(obj, p, path, name);
+	show(obj, path, name);
 	me.up = path;
 	me.elem = name;
 	me.elem_len = strlen(name);
@@ -88,14 +88,14 @@ static void process_tree(struct rev_info *revs,
 		if (S_ISDIR(entry.mode))
 			process_tree(revs,
 				     lookup_tree(entry.sha1),
-				     p, &me, entry.path);
+				     show, &me, entry.path);
 		else if (S_ISGITLINK(entry.mode))
 			process_gitlink(revs, entry.sha1,
-					p, &me, entry.path);
+					show, &me, entry.path);
 		else
 			process_blob(revs,
 				     lookup_blob(entry.sha1),
-				     p, &me, entry.path);
+				     show, &me, entry.path);
 	}
 	free(tree->buffer);
 	tree->buffer = NULL;
@@ -134,6 +134,11 @@ void mark_edges_uninteresting(struct commit_list *list,
 	}
 }
 
+static void add_pending_tree(struct rev_info *revs, struct tree *tree)
+{
+	add_pending_object(revs, &tree->object, "");
+}
+
 void traverse_commit_list(struct rev_info *revs,
 			  show_commit_fn show_commit,
 			  show_object_fn show_object,
@@ -141,10 +146,9 @@ void traverse_commit_list(struct rev_info *revs,
 {
 	int i;
 	struct commit *commit;
-	struct object_array objects = { 0, 0, NULL };
 
 	while ((commit = get_revision(revs)) != NULL) {
-		process_tree(revs, commit->tree, &objects, NULL, "");
+		add_pending_tree(revs, commit->tree);
 		show_commit(commit, data);
 	}
 	for (i = 0; i < revs->pending.nr; i++) {
@@ -155,25 +159,22 @@ void traverse_commit_list(struct rev_info *revs,
 			continue;
 		if (obj->type == OBJ_TAG) {
 			obj->flags |= SEEN;
-			add_object_array(obj, name, &objects);
+			show_object(obj, NULL, name);
 			continue;
 		}
 		if (obj->type == OBJ_TREE) {
-			process_tree(revs, (struct tree *)obj, &objects,
+			process_tree(revs, (struct tree *)obj, show_object,
 				     NULL, name);
 			continue;
 		}
 		if (obj->type == OBJ_BLOB) {
-			process_blob(revs, (struct blob *)obj, &objects,
+			process_blob(revs, (struct blob *)obj, show_object,
 				     NULL, name);
 			continue;
 		}
 		die("unknown pending object %s (%s)",
 		    sha1_to_hex(obj->sha1), name);
 	}
-	for (i = 0; i < objects.nr; i++)
-		show_object(&objects.objects[i], data);
-	free(objects.objects);
 	if (revs->pending.nr) {
 		free(revs->pending.objects);
 		revs->pending.nr = 0;
diff --git a/list-objects.h b/list-objects.h
index 47fae2e468..d65dbf03e6 100644
--- a/list-objects.h
+++ b/list-objects.h
@@ -2,7 +2,7 @@
 #define LIST_OBJECTS_H
 
 typedef void (*show_commit_fn)(struct commit *, void *);
-typedef void (*show_object_fn)(struct object_array_entry *, void *);
+typedef void (*show_object_fn)(struct object *, const struct name_path *, const char *);
 typedef void (*show_edge_fn)(struct commit *);
 
 void traverse_commit_list(struct rev_info *, show_commit_fn, show_object_fn, void *);
diff --git a/refs.c b/refs.c
index 82afb87684..e65a3b4c4e 100644
--- a/refs.c
+++ b/refs.c
@@ -1681,7 +1681,7 @@ static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
 	return;
 }
 
-char *shorten_unambiguous_ref(const char *ref)
+char *shorten_unambiguous_ref(const char *ref, int strict)
 {
 	int i;
 	static char **scanf_fmts;
@@ -1718,6 +1718,7 @@ char *shorten_unambiguous_ref(const char *ref)
 	/* skip first rule, it will always match */
 	for (i = nr_rules - 1; i > 0 ; --i) {
 		int j;
+		int rules_to_fail = i;
 		int short_name_len;
 
 		if (1 != sscanf(ref, scanf_fmts[i], short_name))
@@ -1725,15 +1726,26 @@ char *shorten_unambiguous_ref(const char *ref)
 
 		short_name_len = strlen(short_name);
 
+		/*
+		 * in strict mode, all (except the matched one) rules
+		 * must fail to resolve to a valid non-ambiguous ref
+		 */
+		if (strict)
+			rules_to_fail = nr_rules;
+
 		/*
 		 * check if the short name resolves to a valid ref,
 		 * but use only rules prior to the matched one
 		 */
-		for (j = 0; j < i; j++) {
+		for (j = 0; j < rules_to_fail; j++) {
 			const char *rule = ref_rev_parse_rules[j];
 			unsigned char short_objectname[20];
 			char refname[PATH_MAX];
 
+			/* skip matched rule */
+			if (i == j)
+				continue;
+
 			/*
 			 * the short name is ambiguous, if it resolves
 			 * (with this previous rule) to a valid ref
@@ -1749,7 +1761,7 @@ char *shorten_unambiguous_ref(const char *ref)
 		 * short name is non-ambiguous if all previous rules
 		 * haven't resolved to a valid ref
 		 */
-		if (j == i)
+		if (j == rules_to_fail)
 			return short_name;
 	}
 
diff --git a/refs.h b/refs.h
index 50abbbb2aa..29d17a48e4 100644
--- a/refs.h
+++ b/refs.h
@@ -81,7 +81,7 @@ extern int for_each_reflog(each_ref_fn, void *);
 extern int check_ref_format(const char *target);
 
 extern const char *prettify_ref(const struct ref *ref);
-extern char *shorten_unambiguous_ref(const char *ref);
+extern char *shorten_unambiguous_ref(const char *ref, int strict);
 
 /** rename ref, return 0 on success **/
 extern int rename_ref(const char *oldref, const char *newref, const char *logmsg);
diff --git a/remote.c b/remote.c
index a06761ace8..41c5b59736 100644
--- a/remote.c
+++ b/remote.c
@@ -1461,11 +1461,7 @@ int format_tracking_info(struct branch *branch, struct strbuf *sb)
 		return 0;
 
 	base = branch->merge[0]->dst;
-	if (!prefixcmp(base, "refs/remotes/")) {
-		base += strlen("refs/remotes/");
-	} else if (!prefixcmp(base, "refs/heads/")) {
-		base += strlen("refs/heads/");
-	}
+	base = shorten_unambiguous_ref(base, 0);
 	if (!num_theirs)
 		strbuf_addf(sb, "Your branch is ahead of '%s' "
 			    "by %d commit%s.\n",
@@ -1504,7 +1500,7 @@ static int one_local_ref(const char *refname, const unsigned char *sha1, int fla
 
 struct ref *get_local_heads(void)
 {
-	struct ref *local_refs, **local_tail = &local_refs;
+	struct ref *local_refs = NULL, **local_tail = &local_refs;
 	for_each_ref(one_local_ref, &local_tail);
 	return local_refs;
 }
diff --git a/revision.c b/revision.c
index b6215cc72c..bd0ea34af0 100644
--- a/revision.c
+++ b/revision.c
@@ -15,9 +15,9 @@
 
 volatile show_early_output_fn_t show_early_output;
 
-static char *path_name(struct name_path *path, const char *name)
+char *path_name(const struct name_path *path, const char *name)
 {
-	struct name_path *p;
+	const struct name_path *p;
 	char *n, *m;
 	int nlen = strlen(name);
 	int len = nlen + 1;
diff --git a/revision.h b/revision.h
index 5adfc91405..be39e7d386 100644
--- a/revision.h
+++ b/revision.h
@@ -146,6 +146,8 @@ struct name_path {
 	const char *elem;
 };
 
+char *path_name(const struct name_path *path, const char *name);
+
 extern void add_object(struct object *obj,
 		       struct object_array *p,
 		       struct name_path *path,
diff --git a/shell.c b/shell.c
index e3393690dd..b968be79f4 100644
--- a/shell.c
+++ b/shell.c
@@ -40,6 +40,7 @@ static struct commands {
 } cmd_list[] = {
 	{ "git-receive-pack", do_generic_cmd },
 	{ "git-upload-pack", do_generic_cmd },
+	{ "git-upload-archive", do_generic_cmd },
 	{ "cvs", do_cvs_cmd },
 	{ NULL },
 };
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index 5ac0a273a9..e3d846420d 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -199,4 +199,13 @@ test_expect_success 'init honors global core.sharedRepository' '
 	x`git config -f shared-honor-global/.git/config core.sharedRepository`
 '
 
+test_expect_success 'init rejects insanely long --template' '
+	(
+		insane=$(printf "x%09999dx" 1) &&
+		mkdir test &&
+		cd test &&
+		test_must_fail git init --template=$insane
+	)
+'
+
 test_done
diff --git a/t/t1303-wacky-config.sh b/t/t1303-wacky-config.sh
index 1983076c75..080117c6bc 100755
--- a/t/t1303-wacky-config.sh
+++ b/t/t1303-wacky-config.sh
@@ -10,7 +10,7 @@ setup() {
 
 check() {
 	echo "$2" >expected
-	git config --get "$1" >actual
+	git config --get "$1" >actual 2>&1
 	test_cmp actual expected
 }
 
@@ -40,4 +40,11 @@ test_expect_success 'make sure git config escapes section names properly' '
 	check "$SECTION" bar
 '
 
+LONG_VALUE=$(printf "x%01021dx a" 7)
+test_expect_success 'do not crash on special long config line' '
+	setup &&
+	git config section.key "$LONG_VALUE" &&
+	check section.key "fatal: bad config file line 2 in .git/config"
+'
+
 test_done
diff --git a/t/t4130-apply-criss-cross-rename.sh b/t/t4130-apply-criss-cross-rename.sh
new file mode 100755
index 0000000000..8623dbebab
--- /dev/null
+++ b/t/t4130-apply-criss-cross-rename.sh
@@ -0,0 +1,38 @@
+#!/bin/sh
+
+test_description='git apply handling criss-cross rename patch.'
+. ./test-lib.sh
+
+create_file() {
+	cnt=0
+	while test $cnt -le 100
+	do
+		cnt=$(($cnt + 1))
+		echo "$2" >> "$1"
+	done
+}
+
+test_expect_success 'setup' '
+	create_file file1 "File1 contents" &&
+	create_file file2 "File2 contents" &&
+	git add file1 file2 &&
+	git commit -m 1
+'
+
+test_expect_success 'criss-cross rename' '
+	mv file1 tmp &&
+	mv file2 file1 &&
+	mv tmp file2
+'
+
+test_expect_success 'diff -M -B' '
+	git diff -M -B > diff &&
+	git reset --hard
+
+'
+
+test_expect_success 'apply' '
+	git apply diff
+'
+
+test_done
diff --git a/t/t4150-am.sh b/t/t4150-am.sh
index a8aa02e936..979e3ca79e 100755
--- a/t/t4150-am.sh
+++ b/t/t4150-am.sh
@@ -294,4 +294,19 @@ test_expect_success 'am --ignore-date' '
 	echo "$at" | grep "+0000"
 '
 
+test_expect_success 'am into an unborn branch' '
+	rm -fr subdir &&
+	mkdir -p subdir &&
+	git format-patch --numbered-files -o subdir -1 first &&
+	(
+		cd subdir &&
+		git init &&
+		git am 1
+	) &&
+	result=$(
+		cd subdir && git rev-parse HEAD^{tree}
+	) &&
+	test "z$result" = "z$(git rev-parse first^{tree})"
+'
+
 test_done
diff --git a/t/t5000-tar-tree.sh b/t/t5000-tar-tree.sh
index 7641e0dd46..abb41b07ef 100755
--- a/t/t5000-tar-tree.sh
+++ b/t/t5000-tar-tree.sh
@@ -50,7 +50,7 @@ test_expect_success \
 test_expect_success \
     'add ignored file' \
     'echo ignore me >a/ignored &&
-     echo ignored export-ignore >.gitattributes'
+     echo ignored export-ignore >.git/info/attributes'
 
 test_expect_success \
     'add files to repository' \
@@ -64,7 +64,7 @@ test_expect_success \
 test_expect_success \
     'create bare clone' \
     'git clone --bare . bare.git &&
-     cp .gitattributes bare.git/info/attributes'
+     cp .git/info/attributes bare.git/info/attributes'
 
 test_expect_success \
     'remove ignored file' \
@@ -139,10 +139,11 @@ test_expect_success \
 
 test_expect_success \
     'create archives with substfiles' \
-    'echo "substfile?" export-subst >a/.gitattributes &&
+    'cp .git/info/attributes .git/info/attributes.before &&
+     echo "substfile?" export-subst >>.git/info/attributes &&
      git archive HEAD >f.tar &&
      git archive --prefix=prefix/ HEAD >g.tar &&
-     rm a/.gitattributes'
+     mv .git/info/attributes.before .git/info/attributes'
 
 test_expect_success \
     'extract substfiles' \
diff --git a/t/t5001-archive-attr.sh b/t/t5001-archive-attr.sh
new file mode 100755
index 0000000000..426b319bd3
--- /dev/null
+++ b/t/t5001-archive-attr.sh
@@ -0,0 +1,91 @@
+#!/bin/sh
+
+test_description='git archive attribute tests'
+
+. ./test-lib.sh
+
+SUBSTFORMAT=%H%n
+
+test_expect_exists() {
+	test_expect_success " $1 exists" "test -e $1"
+}
+
+test_expect_missing() {
+	test_expect_success " $1 does not exist" "test ! -e $1"
+}
+
+test_expect_success 'setup' '
+	echo ignored >ignored &&
+	echo ignored export-ignore >>.git/info/attributes &&
+	git add ignored &&
+
+	echo ignored by tree >ignored-by-tree &&
+	echo ignored-by-tree export-ignore >.gitattributes &&
+	git add ignored-by-tree .gitattributes &&
+
+	echo ignored by worktree >ignored-by-worktree &&
+	echo ignored-by-worktree export-ignore >.gitattributes &&
+	git add ignored-by-worktree &&
+
+	printf "A\$Format:%s\$O" "$SUBSTFORMAT" >nosubstfile &&
+	printf "A\$Format:%s\$O" "$SUBSTFORMAT" >substfile1 &&
+	printf "A not substituted O" >substfile2 &&
+	echo "substfile?" export-subst >>.git/info/attributes &&
+	git add nosubstfile substfile1 substfile2 &&
+
+	git commit -m. &&
+
+	git clone --bare . bare &&
+	cp .git/info/attributes bare/info/attributes
+'
+
+test_expect_success 'git archive' '
+	git archive HEAD >archive.tar &&
+	(mkdir archive && cd archive && "$TAR" xf -) <archive.tar
+'
+
+test_expect_missing	archive/ignored
+test_expect_missing	archive/ignored-by-tree
+test_expect_exists	archive/ignored-by-worktree
+
+test_expect_success 'git archive with worktree attributes' '
+	git archive --worktree-attributes HEAD >worktree.tar &&
+	(mkdir worktree && cd worktree && "$TAR" xf -) <worktree.tar
+'
+
+test_expect_missing	worktree/ignored
+test_expect_exists	worktree/ignored-by-tree
+test_expect_missing	worktree/ignored-by-worktree
+
+test_expect_success 'git archive vs. bare' '
+	(cd bare && git archive HEAD) >bare-archive.tar &&
+	test_cmp archive.tar bare-archive.tar
+'
+
+test_expect_success 'git archive with worktree attributes, bare' '
+	(cd bare && git archive --worktree-attributes HEAD) >bare-worktree.tar &&
+	(mkdir bare-worktree && cd bare-worktree && "$TAR" xf -) <bare-worktree.tar
+'
+
+test_expect_missing	bare-worktree/ignored
+test_expect_exists	bare-worktree/ignored-by-tree
+test_expect_exists	bare-worktree/ignored-by-worktree
+
+test_expect_success 'export-subst' '
+	git log "--pretty=format:A${SUBSTFORMAT}O" HEAD >substfile1.expected &&
+	test_cmp nosubstfile archive/nosubstfile &&
+	test_cmp substfile1.expected archive/substfile1 &&
+	test_cmp substfile2 archive/substfile2
+'
+
+test_expect_success 'git tar-tree vs. git archive with worktree attributes' '
+	git tar-tree HEAD >tar-tree.tar &&
+	test_cmp worktree.tar tar-tree.tar
+'
+
+test_expect_success 'git tar-tree vs. git archive with worktree attrs, bare' '
+	(cd bare && git tar-tree HEAD) >bare-tar-tree.tar &&
+	test_cmp bare-worktree.tar bare-tar-tree.tar
+'
+
+test_done
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index daf02d5c10..8052c86ad3 100755
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -301,10 +301,11 @@ test_expect_success 'Check for invalid refname format' '
 
 cat >expected <<\EOF
 heads/master
-master
+tags/master
 EOF
 
-test_expect_success 'Check ambiguous head and tag refs' '
+test_expect_success 'Check ambiguous head and tag refs (strict)' '
+	git config --bool core.warnambiguousrefs true &&
 	git checkout -b newtag &&
 	echo "Using $datestamp" > one &&
 	git add one &&
@@ -315,12 +316,23 @@ test_expect_success 'Check ambiguous head and tag refs' '
 	test_cmp expected actual
 '
 
+cat >expected <<\EOF
+heads/master
+master
+EOF
+
+test_expect_success 'Check ambiguous head and tag refs (loose)' '
+	git config --bool core.warnambiguousrefs false &&
+	git for-each-ref --format "%(refname:short)" refs/heads/master refs/tags/master >actual &&
+	test_cmp expected actual
+'
+
 cat >expected <<\EOF
 heads/ambiguous
 ambiguous
 EOF
 
-test_expect_success 'Check ambiguous head and tag refs II' '
+test_expect_success 'Check ambiguous head and tag refs II (loose)' '
 	git checkout master &&
 	git tag ambiguous testtag^0 &&
 	git branch ambiguous testtag^0 &&
diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
new file mode 100755
index 0000000000..2586f864a0
--- /dev/null
+++ b/t/t7800-difftool.sh
@@ -0,0 +1,211 @@
+#!/bin/sh
+#
+# Copyright (c) 2009 David Aguilar
+#
+
+test_description='git-difftool
+
+Testing basic diff tool invocation
+'
+
+. ./test-lib.sh
+
+remove_config_vars()
+{
+	# Unset all config variables used by git-difftool
+	git config --unset diff.tool
+	git config --unset difftool.test-tool.cmd
+	git config --unset difftool.prompt
+	git config --unset merge.tool
+	git config --unset mergetool.test-tool.cmd
+	return 0
+}
+
+restore_test_defaults()
+{
+	# Restores the test defaults used by several tests
+	remove_config_vars
+	unset GIT_DIFF_TOOL
+	unset GIT_MERGE_TOOL
+	unset GIT_DIFFTOOL_PROMPT
+	unset GIT_DIFFTOOL_NO_PROMPT
+	git config diff.tool test-tool &&
+	git config difftool.test-tool.cmd 'cat $LOCAL'
+}
+
+prompt_given()
+{
+	prompt="$1"
+	test "$prompt" = "Hit return to launch 'test-tool': branch"
+}
+
+# Create a file on master and change it on branch
+test_expect_success 'setup' '
+	echo master >file &&
+	git add file &&
+	git commit -m "added file" &&
+
+	git checkout -b branch master &&
+	echo branch >file &&
+	git commit -a -m "branch changed file" &&
+	git checkout master
+'
+
+# Configure a custom difftool.<tool>.cmd and use it
+test_expect_success 'custom commands' '
+	restore_test_defaults &&
+	git config difftool.test-tool.cmd "cat \$REMOTE" &&
+
+	diff=$(git difftool --no-prompt branch) &&
+	test "$diff" = "master" &&
+
+	restore_test_defaults &&
+	diff=$(git difftool --no-prompt branch) &&
+	test "$diff" = "branch"
+'
+
+# Ensures that git-difftool ignores bogus --tool values
+test_expect_success 'difftool ignores bad --tool values' '
+	diff=$(git difftool --no-prompt --tool=bogus-tool branch)
+	test "$?" = 1 &&
+	test "$diff" = ""
+'
+
+# Specify the diff tool using $GIT_DIFF_TOOL
+test_expect_success 'GIT_DIFF_TOOL variable' '
+	git config --unset diff.tool
+	GIT_DIFF_TOOL=test-tool &&
+	export GIT_DIFF_TOOL &&
+
+	diff=$(git difftool --no-prompt branch) &&
+	test "$diff" = "branch" &&
+
+	restore_test_defaults
+'
+
+# Test the $GIT_*_TOOL variables and ensure
+# that $GIT_DIFF_TOOL always wins unless --tool is specified
+test_expect_success 'GIT_DIFF_TOOL overrides' '
+	git config diff.tool bogus-tool &&
+	git config merge.tool bogus-tool &&
+
+	GIT_MERGE_TOOL=test-tool &&
+	export GIT_MERGE_TOOL &&
+	diff=$(git difftool --no-prompt branch) &&
+	test "$diff" = "branch" &&
+	unset GIT_MERGE_TOOL &&
+
+	GIT_MERGE_TOOL=bogus-tool &&
+	GIT_DIFF_TOOL=test-tool &&
+	export GIT_MERGE_TOOL &&
+	export GIT_DIFF_TOOL &&
+
+	diff=$(git difftool --no-prompt branch) &&
+	test "$diff" = "branch" &&
+
+	GIT_DIFF_TOOL=bogus-tool &&
+	export GIT_DIFF_TOOL &&
+
+	diff=$(git difftool --no-prompt --tool=test-tool branch) &&
+	test "$diff" = "branch" &&
+
+	restore_test_defaults
+'
+
+# Test that we don't have to pass --no-prompt to difftool
+# when $GIT_DIFFTOOL_NO_PROMPT is true
+test_expect_success 'GIT_DIFFTOOL_NO_PROMPT variable' '
+	GIT_DIFFTOOL_NO_PROMPT=true &&
+	export GIT_DIFFTOOL_NO_PROMPT &&
+
+	diff=$(git difftool branch) &&
+	test "$diff" = "branch" &&
+
+	restore_test_defaults
+'
+
+# git-difftool supports the difftool.prompt variable.
+# Test that GIT_DIFFTOOL_PROMPT can override difftool.prompt = false
+test_expect_success 'GIT_DIFFTOOL_PROMPT variable' '
+	git config difftool.prompt false &&
+	GIT_DIFFTOOL_PROMPT=true &&
+	export GIT_DIFFTOOL_PROMPT &&
+
+	prompt=$(echo | git difftool --prompt branch | tail -1) &&
+	prompt_given "$prompt" &&
+
+	restore_test_defaults
+'
+
+# Test that we don't have to pass --no-prompt when difftool.prompt is false
+test_expect_success 'difftool.prompt config variable is false' '
+	git config difftool.prompt false &&
+
+	diff=$(git difftool branch) &&
+	test "$diff" = "branch" &&
+
+	restore_test_defaults
+'
+
+# Test that the -y flag can override difftool.prompt = true
+test_expect_success 'difftool.prompt can overridden with -y' '
+	git config difftool.prompt true &&
+
+	diff=$(git difftool -y branch) &&
+	test "$diff" = "branch" &&
+
+	restore_test_defaults
+'
+
+# Test that the --prompt flag can override difftool.prompt = false
+test_expect_success 'difftool.prompt can overridden with --prompt' '
+	git config difftool.prompt false &&
+
+	prompt=$(echo | git difftool --prompt branch | tail -1) &&
+	prompt_given "$prompt" &&
+
+	restore_test_defaults
+'
+
+# Test that the last flag passed on the command-line wins
+test_expect_success 'difftool last flag wins' '
+	diff=$(git difftool --prompt --no-prompt branch) &&
+	test "$diff" = "branch" &&
+
+	restore_test_defaults &&
+
+	prompt=$(echo | git difftool --no-prompt --prompt branch | tail -1) &&
+	prompt_given "$prompt" &&
+
+	restore_test_defaults
+'
+
+# git-difftool falls back to git-mergetool config variables
+# so test that behavior here
+test_expect_success 'difftool + mergetool config variables' '
+	remove_config_vars
+	git config merge.tool test-tool &&
+	git config mergetool.test-tool.cmd "cat \$LOCAL" &&
+
+	diff=$(git difftool --no-prompt branch) &&
+	test "$diff" = "branch" &&
+
+	# set merge.tool to something bogus, diff.tool to test-tool
+	git config merge.tool bogus-tool &&
+	git config diff.tool test-tool &&
+
+	diff=$(git difftool --no-prompt branch) &&
+	test "$diff" = "branch" &&
+
+	restore_test_defaults
+'
+
+test_expect_success 'difftool.<tool>.path' '
+	git config difftool.tkdiff.path echo &&
+	diff=$(git difftool --tool=tkdiff --no-prompt branch) &&
+	git config --unset difftool.tkdiff.path &&
+	lines=$(echo "$diff" | grep file | wc -l) &&
+	test "$lines" -eq 1
+'
+
+test_done
diff --git a/templates/hooks--update.sample b/templates/hooks--update.sample
index a3f68ae3b4..f8bf490cff 100755
--- a/templates/hooks--update.sample
+++ b/templates/hooks--update.sample
@@ -16,6 +16,9 @@
 # hooks.allowdeletebranch
 #   This boolean sets whether deleting branches will be allowed in the
 #   repository.  By default they won't be.
+# hooks.denycreatebranch
+#   This boolean sets whether remotely creating branches will be denied
+#   in the repository.  By default this is allowed.
 #
 
 # --- Command line
@@ -39,6 +42,7 @@ fi
 # --- Config
 allowunannotated=$(git config --bool hooks.allowunannotated)
 allowdeletebranch=$(git config --bool hooks.allowdeletebranch)
+denycreatebranch=$(git config --bool hooks.denycreatebranch)
 allowdeletetag=$(git config --bool hooks.allowdeletetag)
 
 # check for no description
@@ -52,7 +56,8 @@ esac
 
 # --- Check types
 # if $newrev is 0000...0000, it's a commit to delete a ref.
-if [ "$newrev" = "0000000000000000000000000000000000000000" ]; then
+zero="0000000000000000000000000000000000000000"
+if [ "$newrev" = "$zero" ]; then
 	newrev_type=delete
 else
 	newrev_type=$(git-cat-file -t $newrev)
@@ -80,6 +85,10 @@ case "$refname","$newrev_type" in
 		;;
 	refs/heads/*,commit)
 		# branch
+		if [ "$oldrev" = "$zero" -a "$denycreatebranch" = "true" ]; then
+			echo "*** Creating a branch is not allowed in this repository" >&2
+			exit 1
+		fi
 		;;
 	refs/heads/*,delete)
 		# delete branch
diff --git a/unpack-trees.c b/unpack-trees.c
index 6847c2d966..e4eb8fa3af 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -87,7 +87,8 @@ static int check_updates(struct unpack_trees_options *o)
 		cnt = 0;
 	}
 
-	git_attr_set_direction(GIT_ATTR_CHECKOUT, &o->result);
+	if (o->update)
+		git_attr_set_direction(GIT_ATTR_CHECKOUT, &o->result);
 	for (i = 0; i < index->cache_nr; i++) {
 		struct cache_entry *ce = index->cache[i];
 
@@ -112,7 +113,8 @@ static int check_updates(struct unpack_trees_options *o)
 		}
 	}
 	stop_progress(&progress);
-	git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
+	if (o->update)
+		git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
 	return errs != 0;
 }
 
diff --git a/upload-pack.c b/upload-pack.c
index 495c99f80a..edc7861228 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -78,20 +78,22 @@ static void show_commit(struct commit *commit, void *data)
 	commit->buffer = NULL;
 }
 
-static void show_object(struct object_array_entry *p, void *data)
+static void show_object(struct object *obj, const struct name_path *path, const char *component)
 {
 	/* An object with name "foo\n0000000..." can be used to
 	 * confuse downstream git-pack-objects very badly.
 	 */
-	const char *ep = strchr(p->name, '\n');
+	const char *name = path_name(path, component);
+	const char *ep = strchr(name, '\n');
 	if (ep) {
-		fprintf(pack_pipe, "%s %.*s\n", sha1_to_hex(p->item->sha1),
-		       (int) (ep - p->name),
-		       p->name);
+		fprintf(pack_pipe, "%s %.*s\n", sha1_to_hex(obj->sha1),
+		       (int) (ep - name),
+		       name);
 	}
 	else
 		fprintf(pack_pipe, "%s %s\n",
-				sha1_to_hex(p->item->sha1), p->name);
+				sha1_to_hex(obj->sha1), name);
+	free((char *)name);
 }
 
 static void show_edge(struct commit *commit)