[04/17] path-walk: allow visiting tags

Commit Message

Derrick Stolee Oct. 8, 2024, 2:11 p.m. UTC

From: Derrick Stolee <[e-mail]>

In anticipation of using the path-walk API to analyze tags or include
them in a pack-file, add the ability to walk the tags that were included
in the revision walk.

When these tag objects point to blobs or trees, we need to make sure
those objects are also visited. Treat tagged trees as root trees, but
put the tagged blobs in their own category.

Be careful about objects that are referred to by multiple references.

Co-authored-by: Johannes Schindelin <[e-mail]>
Signed-off-by: Johannes Schindelin <[e-mail]>
Signed-off-by: Derrick Stolee <[e-mail]>
---
 Documentation/technical/api-path-walk.txt |  2 +-
 path-walk.c                               | 76 ++++++++++++++++++++
 path-walk.h                               |  2 +
 t/helper/test-path-walk.c                 | 13 +++-
 t/t6601-path-walk.sh                      | 85 +++++++++++++++++++++--
 5 files changed, 170 insertions(+), 8 deletions(-)

Patch

diff --git a/Documentation/technical/api-path-walk.txt b/Documentation/technical/api-path-walk.txt
index b7ae476ea0a..5fea1d1db17 100644
--- a/Documentation/technical/api-path-walk.txt
+++ b/Documentation/technical/api-path-walk.txt
@@ -48,7 +48,7 @@  If you want the path-walk API to emit `UNINTERESTING` objects based on the
 commit walk's boundary, be sure to set `revs.boundary` so the boundary
 commits are emitted.
 
-`commits`, `blobs`, `trees`::
+`commits`, `blobs`, `trees`, `tags`::
 	By default, these members are enabled and signal that the path-walk
 	API should call the `path_fn` on objects of these types. Specialized
 	applications could disable some options to make it simpler to walk
diff --git a/path-walk.c b/path-walk.c
index 22e1aa13f31..7cd461adf47 100644
--- a/path-walk.c
+++ b/path-walk.c
@@ -13,6 +13,7 @@ 
 #include "revision.h"
 #include "string-list.h"
 #include "strmap.h"
+#include "tag.h"
 #include "trace2.h"
 #include "tree.h"
 #include "tree-walk.h"
@@ -204,13 +205,88 @@  int walk_objects_by_path(struct path_walk_info *info)
 	CALLOC_ARRAY(commit_list, 1);
 	commit_list->type = OBJ_COMMIT;
 
+	if (info->tags)
+		info->revs->tag_objects = 1;
+
 	/* Insert a single list for the root tree into the paths. */
 	CALLOC_ARRAY(root_tree_list, 1);
 	root_tree_list->type = OBJ_TREE;
 	strmap_put(&ctx.paths_to_lists, root_path, root_tree_list);
+
+	/*
+	 * Set these values before preparing the walk to catch
+	 * lightweight tags pointing to non-commits.
+	 */
+	info->revs->blob_objects = info->blobs;
+	info->revs->tree_objects = info->trees;
+
 	if (prepare_revision_walk(info->revs))
 		die(_("failed to setup revision walk"));
 
+	info->revs->blob_objects = info->revs->tree_objects = 0;
+
+	if (info->tags) {
+		struct oid_array tagged_blob_list = OID_ARRAY_INIT;
+		struct oid_array tags = OID_ARRAY_INIT;
+
+		trace2_region_enter("path-walk", "tag-walk", info->revs->repo);
+
+		/*
+		 * Walk any pending objects at this point, but they should only
+		 * be tags.
+		 */
+		for (size_t i = 0; i < info->revs->pending.nr; i++) {
+			struct object_array_entry *pending = info->revs->pending.objects + i;
+			struct object *obj = pending->item;
+
+			if (obj->type == OBJ_COMMIT || obj->flags & SEEN)
+				continue;
+
+			obj->flags |= SEEN;
+
+			while (obj->type == OBJ_TAG) {
+				struct tag *tag = lookup_tag(info->revs->repo,
+							     &obj->oid);
+				if (oid_array_lookup(&tags, &obj->oid) < 0)
+					oid_array_append(&tags, &obj->oid);
+				obj = tag->tagged;
+			}
+
+			switch (obj->type) {
+			case OBJ_TREE:
+				if (info->trees &&
+				    oid_array_lookup(&root_tree_list->oids, &obj->oid) < 0)
+					oid_array_append(&root_tree_list->oids, &obj->oid);
+				break;
+
+			case OBJ_BLOB:
+				if (info->blobs &&
+				    oid_array_lookup(&tagged_blob_list, &obj->oid) < 0)
+					oid_array_append(&tagged_blob_list, &obj->oid);
+				break;
+
+			case OBJ_COMMIT:
+				/* Make sure it is in the object walk */
+				add_pending_object(info->revs, obj, "");
+				break;
+
+			default:
+				BUG("should not see any other type here");
+			}
+		}
+
+		info->path_fn("", &tags, OBJ_TAG, info->path_fn_data);
+
+		if (tagged_blob_list.nr && info->blobs)
+			info->path_fn("/tagged-blobs", &tagged_blob_list, OBJ_BLOB,
+				      info->path_fn_data);
+
+		trace2_data_intmax("path-walk", ctx.repo, "tags", tags.nr);
+		trace2_region_leave("path-walk", "tag-walk", info->revs->repo);
+		oid_array_clear(&tags);
+		oid_array_clear(&tagged_blob_list);
+	}
+
 	while ((c = get_revision(info->revs))) {
 		struct object_id *oid;
 		struct tree *t;
diff --git a/path-walk.h b/path-walk.h
index 6ef372d8942..3f3b63180ef 100644
--- a/path-walk.h
+++ b/path-walk.h
@@ -37,12 +37,14 @@  struct path_walk_info {
 	int commits;
 	int trees;
 	int blobs;
+	int tags;
 };
 
 #define PATH_WALK_INFO_INIT {   \
 	.blobs = 1,		\
 	.trees = 1,		\
 	.commits = 1,		\
+	.tags = 1,		\
 }
 
 /**
diff --git a/t/helper/test-path-walk.c b/t/helper/test-path-walk.c
index 37c5e3e31e8..c6c60d68749 100644
--- a/t/helper/test-path-walk.c
+++ b/t/helper/test-path-walk.c
@@ -21,6 +21,7 @@  struct path_walk_test_data {
 	uintmax_t commit_nr;
 	uintmax_t tree_nr;
 	uintmax_t blob_nr;
+	uintmax_t tag_nr;
 };
 
 static int emit_block(const char *path, struct oid_array *oids,
@@ -45,6 +46,11 @@  static int emit_block(const char *path, struct oid_array *oids,
 		tdata->blob_nr += oids->nr;
 		break;
 
+	case OBJ_TAG:
+		typestr = "TAG";
+		tdata->tag_nr += oids->nr;
+		break;
+
 	default:
 		BUG("we do not understand this type");
 	}
@@ -66,6 +72,8 @@  int cmd__path_walk(int argc, const char **argv)
 			 N_("toggle inclusion of blob objects")),
 		OPT_BOOL(0, "commits", &info.commits,
 			 N_("toggle inclusion of commit objects")),
+		OPT_BOOL(0, "tags", &info.tags,
+			 N_("toggle inclusion of tag objects")),
 		OPT_BOOL(0, "trees", &info.trees,
 			 N_("toggle inclusion of tree objects")),
 		OPT_END(),
@@ -92,8 +100,9 @@  int cmd__path_walk(int argc, const char **argv)
 
 	printf("commits:%" PRIuMAX "\n"
 	       "trees:%" PRIuMAX "\n"
-	       "blobs:%" PRIuMAX "\n",
-	       data.commit_nr, data.tree_nr, data.blob_nr);
+	       "blobs:%" PRIuMAX "\n"
+	       "tags:%" PRIuMAX "\n",
+	       data.commit_nr, data.tree_nr, data.blob_nr, data.tag_nr);
 
 	return res;
 }
diff --git a/t/t6601-path-walk.sh b/t/t6601-path-walk.sh
index e4788664f93..7758e2529ee 100755
--- a/t/t6601-path-walk.sh
+++ b/t/t6601-path-walk.sh
@@ -7,24 +7,55 @@  test_description='direct path-walk API tests'
 test_expect_success 'setup test repository' '
 	git checkout -b base &&
 
+	# Make some objects that will only be reachable
+	# via non-commit tags.
+	mkdir child &&
+	echo file >child/file &&
+	git add child &&
+	git commit -m "will abandon" &&
+	git tag -a -m "tree" tree-tag HEAD^{tree} &&
+	echo file2 >file2 &&
+	git add file2 &&
+	git commit --amend -m "will abandon" &&
+	git tag tree-tag2 HEAD^{tree} &&
+
+	echo blob >file &&
+	blob_oid=$(git hash-object -t blob -w --stdin <file) &&
+	git tag -a -m "blob" blob-tag "$blob_oid" &&
+	echo blob2 >file2 &&
+	blob2_oid=$(git hash-object -t blob -w --stdin <file2) &&
+	git tag blob-tag2 "$blob2_oid" &&
+
+	rm -fr child file file2 &&
+
 	mkdir left &&
 	mkdir right &&
 	echo a >a &&
 	echo b >left/b &&
 	echo c >right/c &&
 	git add . &&
-	git commit -m "first" &&
+	git commit --amend -m "first" &&
+	git tag -m "first" first HEAD &&
 
 	echo d >right/d &&
 	git add right &&
 	git commit -m "second" &&
+	git tag -a -m "second (under)" second.1 HEAD &&
+	git tag -a -m "second (top)" second.2 second.1 &&
 
+	# Set up file/dir collision in history.
+	rm a &&
+	mkdir a &&
+	echo a >a/a &&
 	echo bb >left/b &&
-	git commit -a -m "third" &&
+	git add a left &&
+	git commit -m "third" &&
+	git tag -a -m "third" third &&
 
 	git checkout -b topic HEAD~1 &&
 	echo cc >right/c &&
-	git commit -a -m "topic"
+	git commit -a -m "topic" &&
+	git tag -a -m "fourth" fourth
 '
 
 test_expect_success 'all' '
@@ -40,19 +71,35 @@  test_expect_success 'all' '
 	TREE::$(git rev-parse base^{tree})
 	TREE::$(git rev-parse base~1^{tree})
 	TREE::$(git rev-parse base~2^{tree})
+	TREE::$(git rev-parse refs/tags/tree-tag^{})
+	TREE::$(git rev-parse refs/tags/tree-tag2^{})
+	TREE:a/:$(git rev-parse base:a)
 	TREE:left/:$(git rev-parse base:left)
 	TREE:left/:$(git rev-parse base~2:left)
 	TREE:right/:$(git rev-parse topic:right)
 	TREE:right/:$(git rev-parse base~1:right)
 	TREE:right/:$(git rev-parse base~2:right)
-	trees:9
+	TREE:child/:$(git rev-parse refs/tags/tree-tag^{}:child)
+	trees:13
 	BLOB:a:$(git rev-parse base~2:a)
+	BLOB:file2:$(git rev-parse refs/tags/tree-tag2^{}:file2)
 	BLOB:left/b:$(git rev-parse base~2:left/b)
 	BLOB:left/b:$(git rev-parse base:left/b)
 	BLOB:right/c:$(git rev-parse base~2:right/c)
 	BLOB:right/c:$(git rev-parse topic:right/c)
 	BLOB:right/d:$(git rev-parse base~1:right/d)
-	blobs:6
+	BLOB:/tagged-blobs:$(git rev-parse refs/tags/blob-tag^{})
+	BLOB:/tagged-blobs:$(git rev-parse refs/tags/blob-tag2^{})
+	BLOB:child/file:$(git rev-parse refs/tags/tree-tag^{}:child/file)
+	blobs:10
+	TAG::$(git rev-parse refs/tags/first)
+	TAG::$(git rev-parse refs/tags/second.1)
+	TAG::$(git rev-parse refs/tags/second.2)
+	TAG::$(git rev-parse refs/tags/third)
+	TAG::$(git rev-parse refs/tags/fourth)
+	TAG::$(git rev-parse refs/tags/tree-tag)
+	TAG::$(git rev-parse refs/tags/blob-tag)
+	tags:7
 	EOF
 
 	sort expect >expect.sorted &&
@@ -83,6 +130,7 @@  test_expect_success 'topic only' '
 	BLOB:right/c:$(git rev-parse topic:right/c)
 	BLOB:right/d:$(git rev-parse base~1:right/d)
 	blobs:5
+	tags:0
 	EOF
 
 	sort expect >expect.sorted &&
@@ -106,6 +154,7 @@  test_expect_success 'topic, not base' '
 	BLOB:right/c:$(git rev-parse topic:right/c)
 	BLOB:right/d:$(git rev-parse topic:right/d)
 	blobs:4
+	tags:0
 	EOF
 
 	sort expect >expect.sorted &&
@@ -126,6 +175,7 @@  test_expect_success 'topic, not base, only blobs' '
 	BLOB:right/c:$(git rev-parse topic:right/c)
 	BLOB:right/d:$(git rev-parse topic:right/d)
 	blobs:4
+	tags:0
 	EOF
 
 	sort expect >expect.sorted &&
@@ -145,6 +195,7 @@  test_expect_success 'topic, not base, only commits' '
 	commits:1
 	trees:0
 	blobs:0
+	tags:0
 	EOF
 
 	sort expect >expect.sorted &&
@@ -164,6 +215,7 @@  test_expect_success 'topic, not base, only trees' '
 	TREE:right/:$(git rev-parse topic:right)
 	trees:3
 	blobs:0
+	tags:0
 	EOF
 
 	sort expect >expect.sorted &&
@@ -191,6 +243,7 @@  test_expect_success 'topic, not base, boundary' '
 	BLOB:right/c:$(git rev-parse topic:right/c)
 	BLOB:right/d:$(git rev-parse base~1:right/d)
 	blobs:5
+	tags:0
 	EOF
 
 	sort expect >expect.sorted &&
@@ -199,4 +252,26 @@  test_expect_success 'topic, not base, boundary' '
 	test_cmp expect.sorted out.sorted
 '
 
+test_expect_success 'trees are reported exactly once' '
+	test_when_finished "rm -rf unique-trees" &&
+	test_create_repo unique-trees &&
+	(
+		cd unique-trees &&
+		mkdir initial &&
+		test_commit initial/file &&
+
+		git switch -c move-to-top &&
+		git mv initial/file.t ./ &&
+		test_tick &&
+		git commit -m moved &&
+
+		git update-ref refs/heads/other HEAD
+	) &&
+
+	test-tool -C unique-trees path-walk -- --all >out &&
+	tree=$(git -C unique-trees rev-parse HEAD:) &&
+	grep "$tree" out >out-filtered &&
+	test_line_count = 1 out-filtered
+'
+
 test_done