Merge branch 'jk/pack-tag-of-tag' into maint

"git pack-objects --include-tag" was taught that when we know that
we are sending an object C, we want a tag B that directly points at
C but also a tag A that points at the tag B.  We used to miss the
intermediate tag B in some cases.

* jk/pack-tag-of-tag:
  pack-objects: walk tag chains for --include-tag
  t5305: simplify packname handling
  t5305: use "git -C"
  t5305: drop "dry-run" of unpack-objects
  t5305: move cleanup into test block

Author: gitster

builtin/pack-objects.c

@@ -2123,14 +2123,43 @@ static void ll_find_deltas(struct object_entry **list, unsigned list_size,
 #define ll_find_deltas(l, s, w, d, p)	find_deltas(l, &s, w, d, p)
 #endif
 
+static void add_tag_chain(const struct object_id *oid)
+{
+	struct tag *tag;
+
+	/*
+	 * We catch duplicates already in add_object_entry(), but we'd
+	 * prefer to do this extra check to avoid having to parse the
+	 * tag at all if we already know that it's being packed (e.g., if
+	 * it was included via bitmaps, we would not have parsed it
+	 * previously).
+	 */
+	if (packlist_find(&to_pack, oid->hash, NULL))
+		return;
+
+	tag = lookup_tag(oid->hash);
+	while (1) {
+		if (!tag || parse_tag(tag) || !tag->tagged)
+			die("unable to pack objects reachable from tag %s",
+			    oid_to_hex(oid));
+
+		add_object_entry(tag->object.oid.hash, OBJ_TAG, NULL, 0);
+
+		if (tag->tagged->type != OBJ_TAG)
+			return;
+
+		tag = (struct tag *)tag->tagged;
+	}
+}
+
 static int add_ref_tag(const char *path, const struct object_id *oid, int flag, void *cb_data)
 {
 	struct object_id peeled;
 
 	if (starts_with(path, "refs/tags/") && /* is a tag? */
 	    !peel_ref(path, peeled.hash)    && /* peelable? */
 	    packlist_find(&to_pack, peeled.hash, NULL))      /* object packed? */
-		add_object_entry(oid->hash, OBJ_TAG, NULL, 0);
+		add_tag_chain(oid);
 	return 0;
 }
 

t/t5305-include-tag.sh

@@ -25,58 +25,94 @@ test_expect_success setup '
 	} >obj-list
 '
 
-rm -rf clone.git
 test_expect_success 'pack without --include-tag' '
-	packname_1=$(git pack-objects \
+	packname=$(git pack-objects \
 		--window=0 \
-		test-1 <obj-list)
+		test-no-include <obj-list)
 '
 
 test_expect_success 'unpack objects' '
-	(
-		GIT_DIR=clone.git &&
-		export GIT_DIR &&
-		git init &&
-		git unpack-objects -n <test-1-${packname_1}.pack &&
-		git unpack-objects <test-1-${packname_1}.pack
-	)
+	rm -rf clone.git &&
+	git init clone.git &&
+	git -C clone.git unpack-objects <test-no-include-${packname}.pack
 '
 
 test_expect_success 'check unpacked result (have commit, no tag)' '
 	git rev-list --objects $commit >list.expect &&
-	(
-		test_must_fail env GIT_DIR=clone.git git cat-file -e $tag &&
-		git rev-list --objects $commit
-	) >list.actual &&
+	test_must_fail git -C clone.git cat-file -e $tag &&
+	git -C clone.git rev-list --objects $commit >list.actual &&
 	test_cmp list.expect list.actual
 '
 
-rm -rf clone.git
 test_expect_success 'pack with --include-tag' '
-	packname_1=$(git pack-objects \
+	packname=$(git pack-objects \
 		--window=0 \
 		--include-tag \
-		test-2 <obj-list)
+		test-include <obj-list)
 '
 
 test_expect_success 'unpack objects' '
-	(
-		GIT_DIR=clone.git &&
-		export GIT_DIR &&
-		git init &&
-		git unpack-objects -n <test-2-${packname_1}.pack &&
-		git unpack-objects <test-2-${packname_1}.pack
-	)
+	rm -rf clone.git &&
+	git init clone.git &&
+	git -C clone.git unpack-objects <test-include-${packname}.pack
 '
 
 test_expect_success 'check unpacked result (have commit, have tag)' '
 	git rev-list --objects mytag >list.expect &&
-	(
-		GIT_DIR=clone.git &&
-		export GIT_DIR &&
-		git rev-list --objects $tag
-	) >list.actual &&
+	git -C clone.git rev-list --objects $tag >list.actual &&
 	test_cmp list.expect list.actual
 '
 
+# A tag of a tag, where the "inner" tag is not otherwise
+# reachable, and a full peel points to a commit reachable from HEAD.
+test_expect_success 'create hidden inner tag' '
+	test_commit commit &&
+	git tag -m inner inner HEAD &&
+	git tag -m outer outer inner &&
+	git tag -d inner
+'
+
+test_expect_success 'pack explicit outer tag' '
+	packname=$(
+		{
+			echo HEAD &&
+			echo outer
+		} |
+		git pack-objects --revs test-hidden-explicit
+	)
+'
+
+test_expect_success 'unpack objects' '
+	rm -rf clone.git &&
+	git init clone.git &&
+	git -C clone.git unpack-objects <test-hidden-explicit-${packname}.pack
+'
+
+test_expect_success 'check unpacked result (have all objects)' '
+	git -C clone.git rev-list --objects $(git rev-parse outer HEAD)
+'
+
+test_expect_success 'pack implied outer tag' '
+	packname=$(
+		echo HEAD |
+		git pack-objects --revs --include-tag test-hidden-implied
+	)
+'
+
+test_expect_success 'unpack objects' '
+	rm -rf clone.git &&
+	git init clone.git &&
+	git -C clone.git unpack-objects <test-hidden-implied-${packname}.pack
+'
+
+test_expect_success 'check unpacked result (have all objects)' '
+	git -C clone.git rev-list --objects $(git rev-parse outer HEAD)
+'
+
+test_expect_success 'single-branch clone can transfer tag' '
+	rm -rf clone.git &&
+	git clone --no-local --single-branch -b master . clone.git &&
+	git -C clone.git fsck
+'
+
 test_done