Merge branch 'jc/pack-peeled' into next

* jc/pack-peeled:
  Store peeled refs in packed-refs file.
  do_for_each_ref: perform the same sanity check for leftovers.
  git-fetch: follow lightweit tags as well.
  Documentation: Correct alternates documentation, document http-alternates

Documentation/repository-layout.txt

@@ -52,9 +52,20 @@ objects/info/packs::
 	by default.
 
 objects/info/alternates::
-	This file records absolute filesystem paths of alternate
-	object stores that this object store borrows objects
-	from, one pathname per line.
+	This file records paths to alternate object stores that
+	this object store borrows objects from, one pathname per
+	line. Note that not only native Git tools use it locally,
+	but the HTTP fetcher also tries to use it remotely; this
+	will usually work if you have relative paths (relative
+	to the object database, not to the repository!) in your
+	alternates file, but it will not work if you use absolute
+	paths unless the absolute path in filesystem and web URL
+	is the same. See also 'objects/info/http-alternates'.
+
+objects/info/http-alternates::
+	This file records URLs to alternate object stores that
+	this object store borrows objects from, to be used when
+	the repository is fetched over HTTP.
 
 refs::
 	References are stored in subdirectories of this

builtin-pack-refs.c

@@ -1,5 +1,7 @@
 #include "cache.h"
 #include "refs.h"
+#include "object.h"
+#include "tag.h"
 
 static const char builtin_pack_refs_usage[] =
 "git-pack-refs [--all] [--prune]";
@@ -29,12 +31,26 @@ static int handle_one_ref(const char *path, const unsigned char *sha1,
 			  int flags, void *cb_data)
 {
 	struct pack_refs_cb_data *cb = cb_data;
+	int is_tag_ref;
 
-	if (!cb->all && strncmp(path, "refs/tags/", 10))
-		return 0;
 	/* Do not pack the symbolic refs */
-	if (!(flags & REF_ISSYMREF))
-		fprintf(cb->refs_file, "%s %s\n", sha1_to_hex(sha1), path);
+	if ((flags & REF_ISSYMREF))
+		return 0;
+	is_tag_ref = !strncmp(path, "refs/tags/", 10);
+	if (!cb->all && !is_tag_ref)
+		return 0;
+
+	fprintf(cb->refs_file, "%s %s\n", sha1_to_hex(sha1), path);
+	if (is_tag_ref) {
+		struct object *o = parse_object(sha1);
+		if (o->type == OBJ_TAG) {
+			o = deref_tag(o, path, 0);
+			if (o)
+				fprintf(cb->refs_file, "%s  %s^{}\n",
+					sha1_to_hex(o->sha1), path);
+		}
+	}
+
 	if (cb->prune && !do_not_prune(flags)) {
 		int namelen = strlen(path) + 1;
 		struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);

builtin-show-ref.c

@@ -13,6 +13,7 @@ static int show_ref(const char *refname, const unsigned char *sha1, int flag, vo
 {
 	struct object *obj;
 	const char *hex;
+	unsigned char peeled[20];
 
 	if (tags_only || heads_only) {
 		int match;
@@ -44,12 +45,15 @@ static int show_ref(const char *refname, const unsigned char *sha1, int flag, vo
 
 match:
 	found_match++;
-	obj = parse_object(sha1);
-	if (!obj) {
-		if (quiet)
-			return 0;
-		die("git-show-ref: bad ref %s (%s)", refname, sha1_to_hex(sha1));
-	}
+
+	/* This changes the semantics slightly that even under quiet we
+	 * detect and return error if the repository is corrupt and
+	 * ref points at a nonexistent object.
+	 */
+	if (!has_sha1_file(sha1))
+		die("git-show-ref: bad ref %s (%s)", refname,
+		    sha1_to_hex(sha1));
+
 	if (quiet)
 		return 0;
 
@@ -58,11 +62,25 @@ match:
 		printf("%s\n", hex);
 	else
 		printf("%s %s\n", hex, refname);
-	if (deref_tags && obj->type == OBJ_TAG) {
-		obj = deref_tag(obj, refname, 0);
-		hex = find_unique_abbrev(obj->sha1, abbrev);
+
+	if (!deref_tags)
+		return 0;
+
+	if ((flag & REF_ISPACKED) && !peel_ref(refname, peeled)) {
+		hex = find_unique_abbrev(peeled, abbrev);
 		printf("%s %s^{}\n", hex, refname);
 	}
+	else {
+		obj = parse_object(sha1);
+		if (!obj)
+			die("git-show-ref: bad ref %s (%s)", refname,
+			    sha1_to_hex(sha1));
+		if (obj->type == OBJ_TAG) {
+			obj = deref_tag(obj, refname, 0);
+			hex = find_unique_abbrev(obj->sha1, abbrev);
+			printf("%s %s^{}\n", hex, refname);
+		}
+	}
 	return 0;
 }
 

git-fetch.sh

@@ -432,10 +432,11 @@ case "$no_tags$tags" in
 		# using local tracking branch.
 		taglist=$(IFS=" " &&
 		git-ls-remote $upload_pack --tags "$remote" |
-		sed -ne 's|^\([0-9a-f]*\)[ 	]\(refs/tags/.*\)^{}$|\1 \2|p' |
+		sed -n	-e 's|^\('"$_x40"'\)	\(refs/tags/.*\)^{}$|\1 \2|p' \
+			-e 's|^\('"$_x40"'\)	\(refs/tags/.*\)$|\1 \2|p' |
 		while read sha1 name
 		do
-			git-show-ref --verify --quiet -- $name && continue
+			git-show-ref --verify --quiet -- "$name" && continue
 			git-check-ref-format "$name" || {
 				echo >&2 "warning: tag ${name} ignored"
 				continue

refs.c

@@ -1,16 +1,18 @@
 #include "refs.h"
 #include "cache.h"
+#include "object.h"
+#include "tag.h"
 
 #include <errno.h>
 
 struct ref_list {
 	struct ref_list *next;
-	unsigned char flag; /* ISSYMREF? ISPACKED? */
+	unsigned char flag; /* ISSYMREF? ISPACKED? ISPEELED? */
 	unsigned char sha1[20];
 	char name[FLEX_ARRAY];
 };
 
-static const char *parse_ref_line(char *line, unsigned char *sha1)
+static const char *parse_ref_line(char *line, unsigned char *sha1, int *flag)
 {
 	/*
 	 * 42: the answer to everything.
@@ -21,6 +23,7 @@ static const char *parse_ref_line(char *line, unsigned char *sha1)
 	 *  +1 (newline at the end of the line)
 	 */
 	int len = strlen(line) - 42;
+	int peeled = 0;
 
 	if (len <= 0)
 		return NULL;
@@ -29,11 +32,24 @@ static const char *parse_ref_line(char *line, unsigned char *sha1)
 	if (!isspace(line[40]))
 		return NULL;
 	line += 41;
-	if (isspace(*line))
-		return NULL;
+
+	if (isspace(*line)) {
+		/* "SHA-1 SP SP refs/tags/tagname^{} LF"? */
+		line++;
+		len--;
+		peeled = 1;
+	}
 	if (line[len] != '\n')
 		return NULL;
 	line[len] = 0;
+
+	if (peeled && (len < 3 || strcmp(line + len - 3, "^{}")))
+		return NULL;
+
+	if (!peeled)
+		*flag &= ~REF_ISPEELED;
+	else
+		*flag |= REF_ISPEELED;
 	return line;
 }
 
@@ -108,10 +124,12 @@ static struct ref_list *get_packed_refs(void)
 			char refline[PATH_MAX];
 			while (fgets(refline, sizeof(refline), f)) {
 				unsigned char sha1[20];
-				const char *name = parse_ref_line(refline, sha1);
+				int flag = REF_ISPACKED;
+				const char *name =
+					parse_ref_line(refline, sha1, &flag);
 				if (!name)
 					continue;
-				list = add_ref(name, sha1, REF_ISPACKED, list);
+				list = add_ref(name, sha1, flag, list);
 			}
 			fclose(f);
 			refs = list;
@@ -207,7 +225,8 @@ const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *
 		if (lstat(path, &st) < 0) {
 			struct ref_list *list = get_packed_refs();
 			while (list) {
-				if (!strcmp(ref, list->name)) {
+				if (!(list->flag & REF_ISPEELED) &&
+				    !strcmp(ref, list->name)) {
 					hashcpy(sha1, list->sha1);
 					if (flag)
 						*flag |= REF_ISPACKED;
@@ -322,6 +341,60 @@ int read_ref(const char *ref, unsigned char *sha1)
 	return -1;
 }
 
+static int do_one_ref(const char *base, each_ref_fn fn, int trim,
+		      void *cb_data, struct ref_list *entry)
+{
+	if (strncmp(base, entry->name, trim))
+		return 0;
+	if (is_null_sha1(entry->sha1))
+		return 0;
+	if (entry->flag & REF_ISPEELED)
+		return 0;
+	if (!has_sha1_file(entry->sha1)) {
+		error("%s does not point to a valid object!", entry->name);
+		return 0;
+	}
+	return fn(entry->name + trim, entry->sha1, entry->flag, cb_data);
+}
+
+int peel_ref(const char *ref, unsigned char *sha1)
+{
+	int flag;
+	unsigned char base[20];
+	struct object *o;
+
+	if (!resolve_ref(ref, base, 1, &flag))
+		return -1;
+
+	if ((flag & REF_ISPACKED)) {
+		struct ref_list *list = get_packed_refs();
+		int len = strlen(ref);
+
+		while (list) {
+			if ((list->flag & REF_ISPEELED) &&
+			    !strncmp(list->name, ref, len) &&
+			    strlen(list->name) == len + 3 &&
+			    !strcmp(list->name + len, "^{}")) {
+				hashcpy(sha1, list->sha1);
+				return 0;
+			}
+			list = list->next;
+		}
+		/* older pack-refs did not leave peeled ones in */
+	}
+
+	/* otherwise ... */
+	o = parse_object(base);
+	if (o->type == OBJ_TAG) {
+		o = deref_tag(o, ref, 0);
+		if (o) {
+			hashcpy(sha1, o->sha1);
+			return 0;
+		}
+	}
+	return -1;
+}
+
 static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 			   void *cb_data)
 {
@@ -343,29 +416,15 @@ static int do_for_each_ref(const char *base, each_ref_fn fn, int trim,
 			entry = packed;
 			packed = packed->next;
 		}
-		if (strncmp(base, entry->name, trim))
-			continue;
-		if (is_null_sha1(entry->sha1))
-			continue;
-		if (!has_sha1_file(entry->sha1)) {
-			error("%s does not point to a valid object!", entry->name);
-			continue;
-		}
-		retval = fn(entry->name + trim, entry->sha1,
-			    entry->flag, cb_data);
+		retval = do_one_ref(base, fn, trim, cb_data, entry);
 		if (retval)
 			return retval;
 	}
 
-	packed = packed ? packed : loose;
-	while (packed) {
-		if (!strncmp(base, packed->name, trim)) {
-			retval = fn(packed->name + trim, packed->sha1,
-				    packed->flag, cb_data);
-			if (retval)
-				return retval;
-		}
-		packed = packed->next;
+	for (packed = packed ? packed : loose; packed; packed = packed->next) {
+		retval = do_one_ref(base, fn, trim, cb_data, packed);
+		if (retval)
+			return retval;
 	}
 	return 0;
 }

refs.h

@@ -16,6 +16,8 @@ struct ref_lock {
  */
 #define REF_ISSYMREF 01
 #define REF_ISPACKED 02
+#define REF_ISPEELED 04 /* internal use */
+
 typedef int each_ref_fn(const char *refname, const unsigned char *sha1, int flags, void *cb_data);
 extern int head_ref(each_ref_fn, void *);
 extern int for_each_ref(each_ref_fn, void *);
@@ -23,6 +25,8 @@ extern int for_each_tag_ref(each_ref_fn, void *);
 extern int for_each_branch_ref(each_ref_fn, void *);
 extern int for_each_remote_ref(each_ref_fn, void *);
 
+extern int peel_ref(const char *, unsigned char *);
+
 /** Reads the refs file specified into sha1 **/
 extern int get_ref_sha1(const char *ref, unsigned char *sha1);
 

t/t5510-fetch.sh

@@ -66,4 +66,20 @@ test_expect_success "fetch test for-merge" '
 	cut -f -2 .git/FETCH_HEAD >actual &&
 	diff expected actual'
 
+test_expect_success 'fetch following tags' '
+
+	cd "$D" &&
+	git tag -a -m 'annotated' anno HEAD &&
+	git tag light HEAD &&
+
+	mkdir four &&
+	cd four &&
+	git init-db &&
+
+	git fetch .. :track &&
+	git show-ref --verify refs/tags/anno &&
+	git show-ref --verify refs/tags/light
+
+'
+
 test_done