Merge branch 'np/addcommit' into next

* np/addcommit:
  make 'git add' a first class user friendly interface to the index

Documentation/git-add.txt

@@ -3,7 +3,7 @@ git-add(1)
 
 NAME
 ----
-git-add - Add files to the index file
+git-add - Add file contents to the changeset to be committed next
 
 SYNOPSIS
 --------
@@ -11,16 +11,31 @@ SYNOPSIS
 
 DESCRIPTION
 -----------
-A simple wrapper for git-update-index to add files to the index,
-for people used to do "cvs add".
+All the changed file contents to be committed together in a single set
+of changes must be "added" with the 'add' command before using the
+'commit' command.  This is not only for adding new files.  Even modified
+files must be added to the set of changes about to be committed.
 
-It only adds non-ignored files, to add ignored files use
+This command can be performed multiple times before a commit. The added
+content corresponds to the state of specified file(s) at the time the
+'add' command is used. This means the 'commit' command will not consider
+subsequent changes to already added content if it is not added again before
+the commit.
+
+The 'git status' command can be used to obtain a summary of what is included
+for the next commit.
+
+This command only adds non-ignored files, to add ignored files use
 "git update-index --add".
 
+Please see gitlink:git-commit[1] for alternative ways to add content to a
+commit.
+
+
 OPTIONS
 -------
 <file>...::
-	Files to add to the index (see gitlink:git-ls-files[1]).
+	Files to add content from.
 
 -n::
         Don't actually add the file(s), just show if they exist.
@@ -34,27 +49,12 @@ OPTIONS
 	for command-line options).
 
 
-DISCUSSION
-----------
-
-The list of <file> given to the command is fed to `git-ls-files`
-command to list files that are not registered in the index and
-are not ignored/excluded by `$GIT_DIR/info/exclude` file or
-`.gitignore` file in each directory.  This means two things:
-
-. You can put the name of a directory on the command line, and
-  the command will add all files in it and its subdirectories;
-
-. Giving the name of a file that is already in index does not
-  run `git-update-index` on that path.
-
-
 EXAMPLES
 --------
 git-add Documentation/\\*.txt::
 
-	Adds all `\*.txt` files that are not in the index under
-	`Documentation` directory and its subdirectories.
+	Adds content from all `\*.txt` files under `Documentation`
+	directory and its subdirectories.
 +
 Note that the asterisk `\*` is quoted from the shell in this
 example; this lets the command to include the files from
@@ -62,15 +62,18 @@ subdirectories of `Documentation/` directory.
 
 git-add git-*.sh::
 
-	Adds all git-*.sh scripts that are not in the index.
+	Considers adding content from all git-*.sh scripts.
 	Because this example lets shell expand the asterisk
 	(i.e. you are listing the files explicitly), it does not
-	add `subdir/git-foo.sh` to the index.
+	consider `subdir/git-foo.sh`.
 
 See Also
 --------
+gitlink:git-status[1]
 gitlink:git-rm[1]
-gitlink:git-ls-files[1]
+gitlink:git-mv[1]
+gitlink:git-commit[1]
+gitlink:git-update-index[1]
 
 Author
 ------

Documentation/tutorial.txt

@@ -87,14 +87,48 @@ thorough description.  Tools that turn commits into email, for
 example, use the first line on the Subject line and the rest of the
 commit in the body.
 
-To add a new file, first create the file, then
 
-------------------------------------------------
-$ git add path/to/new/file
-------------------------------------------------
+Git tracks content not files
+----------------------------
 
-then commit as usual.  No special command is required when removing a
-file; just remove it, then tell `commit` about the file as usual.
+With git you have to explicitly "add" all the changed _content_ you
+want to commit together. This can be done in a few different ways:
+
+1) By using 'git add <file_spec>...'
+
+   This can be performed multiple times before a commit.  Note that this
+   is not only for adding new files.  Even modified files must be
+   added to the set of changes about to be committed.  The "git status"
+   command gives you a summary of what is included so far for the
+   next commit.  When done you should use the 'git commit' command to
+   make it real.
+
+   Note: don't forget to 'add' a file again if you modified it after the
+   first 'add' and before 'commit'. Otherwise only the previous added
+   state of that file will be committed. This is because git tracks
+   content, so what you're really 'add'ing to the commit is the *content*
+   of the file in the state it is in when you 'add' it.
+
+2) By using 'git commit -a' directly
+
+   This is a quick way to automatically 'add' the content from all files
+   that were modified since the previous commit, and perform the actual
+   commit without having to separately 'add' them beforehand.  This will
+   not add content from new files i.e. files that were never added before.
+   Those files still have to be added explicitly before performing a
+   commit.
+
+But here's a twist. If you do 'git commit <file1> <file2> ...' then only
+the  changes belonging to those explicitly specified files will be
+committed, entirely bypassing the current "added" changes. Those "added"
+changes will still remain available for a subsequent commit though.
+
+However, for normal usage you only have to remember 'git add' + 'git commit'
+and/or 'git commit -a'.
+
+
+Viewing the changelog
+---------------------
 
 At any point you can view the history of your changes using
 

builtin-add.c

@@ -94,9 +94,6 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 
 	newfd = hold_lock_file_for_update(&lock_file, get_index_file(), 1);
 
-	if (read_cache() < 0)
-		die("index file corrupt");
-
 	for (i = 1; i < argc; i++) {
 		const char *arg = argv[i];
 
@@ -131,6 +128,9 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 		return 0;
 	}
 
+	if (read_cache() < 0)
+		die("index file corrupt");
+
 	for (i = 0; i < dir.nr; i++)
 		add_file_to_index(dir.entries[i]->name, verbose);
 

wt-status.c

@@ -163,7 +163,7 @@ static void wt_status_print_changed_cb(struct diff_queue_struct *q,
 	int i;
 	if (q->nr)
 		wt_status_print_header("Changed but not updated",
-				"use git-update-index to mark for commit");
+				"use git-add on files to include for commit");
 	for (i = 0; i < q->nr; i++)
 		wt_status_print_filepair(WT_STATUS_CHANGED, q->queue[i]);
 	if (q->nr)