Merge branch 'gc/resolve-alternate-symlinks'

Resolve symbolic links when processing the locations of alternate
object stores, since failing to do so can lead to confusing and buggy
behavior.

* gc/resolve-alternate-symlinks:
  object-file: use real paths when adding alternates

object-file.c

@@ -508,7 +508,9 @@ static int link_alt_odb_entry(struct repository *r, const struct strbuf *entry,
 {
 	struct object_directory *ent;
 	struct strbuf pathbuf = STRBUF_INIT;
+	struct strbuf tmp = STRBUF_INIT;
 	khiter_t pos;
+	int ret = -1;
 
 	if (!is_absolute_path(entry->buf) && relative_base) {
 		strbuf_realpath(&pathbuf, relative_base, 1);
@@ -516,12 +518,12 @@ static int link_alt_odb_entry(struct repository *r, const struct strbuf *entry,
 	}
 	strbuf_addbuf(&pathbuf, entry);
 
-	if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
+	if (!strbuf_realpath(&tmp, pathbuf.buf, 0)) {
 		error(_("unable to normalize alternate object path: %s"),
 		      pathbuf.buf);
-		strbuf_release(&pathbuf);
-		return -1;
+		goto error;
 	}
+	strbuf_swap(&pathbuf, &tmp);
 
 	/*
 	 * The trailing slash after the directory name is given by
@@ -530,10 +532,8 @@ static int link_alt_odb_entry(struct repository *r, const struct strbuf *entry,
 	while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
 		strbuf_setlen(&pathbuf, pathbuf.len - 1);
 
-	if (!alt_odb_usable(r->objects, &pathbuf, normalized_objdir, &pos)) {
-		strbuf_release(&pathbuf);
-		return -1;
-	}
+	if (!alt_odb_usable(r->objects, &pathbuf, normalized_objdir, &pos))
+		goto error;
 
 	CALLOC_ARRAY(ent, 1);
 	/* pathbuf.buf is already in r->objects->odb_by_path */
@@ -548,8 +548,11 @@ static int link_alt_odb_entry(struct repository *r, const struct strbuf *entry,
 
 	/* recursively add alternates */
 	read_info_alternates(r, ent->path, depth + 1);
-
-	return 0;
+	ret = 0;
+ error:
+	strbuf_release(&tmp);
+	strbuf_release(&pathbuf);
+	return ret;
 }
 
 static const char *parse_alt_odb_entry(const char *string,
@@ -596,10 +599,7 @@ static void link_alt_odb_entries(struct repository *r, const char *alt,
 		return;
 	}
 
-	strbuf_add_absolute_path(&objdirbuf, r->objects->odb->path);
-	if (strbuf_normalize_path(&objdirbuf) < 0)
-		die(_("unable to normalize object directory: %s"),
-		    objdirbuf.buf);
+	strbuf_realpath(&objdirbuf, r->objects->odb->path, 1);
 
 	while (*alt) {
 		alt = parse_alt_odb_entry(alt, sep, &entry);

t/t7700-repack.sh

@@ -90,6 +90,22 @@ test_expect_success 'loose objects in alternate ODB are not repacked' '
 	test_has_duplicate_object false
 '
 
+test_expect_success SYMLINKS '--local keeps packs when alternate is objectdir ' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	test_commit -C repo A &&
+	(
+		cd repo &&
+		git repack -a &&
+		ls .git/objects/pack/*.pack >../expect &&
+		ln -s objects .git/alt_objects &&
+		echo "$(pwd)/.git/alt_objects" >.git/objects/info/alternates &&
+		git repack -a -d -l &&
+		ls .git/objects/pack/*.pack >../actual
+	) &&
+	test_cmp expect actual
+'
+
 test_expect_success 'packed obs in alt ODB are repacked even when local repo is packless' '
 	mkdir alt_objects/pack &&
 	mv .git/objects/pack/* alt_objects/pack &&