commit-graph: add repo arg to graph readers

Add a struct repository argument to the functions in commit-graph.h that
read the commit graph. (This commit does not affect functions that write
commit graphs.)

Because the commit graph functions can now read the commit graph of any
repository, the global variable core_commit_graph has been removed.
Instead, the config option core.commitGraph is now read on the first
time in a repository that a commit is attempted to be parsed using its
commit graph.

This commit includes a test that exercises the functionality on an
arbitrary repository that is not the_repository.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

4 files changed, 119 insertions, 0 deletions

diff --git a/t/helper/test-repository.c b/t/helper/test-repository.c
new file mode 100644
index 0000000000..2762ca6562
--- /dev/null
+++ b/t/helper/test-repository.c
@@ -0,0 +1,82 @@
+#include "test-tool.h"
+#include "cache.h"
+#include "commit-graph.h"
+#include "commit.h"
+#include "config.h"
+#include "object-store.h"
+#include "object.h"
+#include "repository.h"
+#include "tree.h"
+
+static void test_parse_commit_in_graph(const char *gitdir, const char *worktree,
+				       const struct object_id *commit_oid)
+{
+	struct repository r;
+	struct commit *c;
+	struct commit_list *parent;
+
+	repo_init(&r, gitdir, worktree);
+
+	c = lookup_commit(&r, commit_oid);
+
+	if (!parse_commit_in_graph(&r, c))
+		die("Couldn't parse commit");
+
+	printf("%"PRItime, c->date);
+	for (parent = c->parents; parent; parent = parent->next)
+		printf(" %s", oid_to_hex(&parent->item->object.oid));
+	printf("\n");
+
+	repo_clear(&r);
+}
+
+static void test_get_commit_tree_in_graph(const char *gitdir,
+					  const char *worktree,
+					  const struct object_id *commit_oid)
+{
+	struct repository r;
+	struct commit *c;
+	struct tree *tree;
+
+	repo_init(&r, gitdir, worktree);
+
+	c = lookup_commit(&r, commit_oid);
+
+	/*
+	 * get_commit_tree_in_graph does not automatically parse the commit, so
+	 * parse it first.
+	 */
+	if (!parse_commit_in_graph(&r, c))
+		die("Couldn't parse commit");
+	tree = get_commit_tree_in_graph(&r, c);
+	if (!tree)
+		die("Couldn't get commit tree");
+
+	printf("%s\n", oid_to_hex(&tree->object.oid));
+
+	repo_clear(&r);
+}
+
+int cmd__repository(int argc, const char **argv)
+{
+	if (argc < 2)
+		die("must have at least 2 arguments");
+	if (!strcmp(argv[1], "parse_commit_in_graph")) {
+		struct object_id oid;
+		if (argc < 5)
+			die("not enough arguments");
+		if (parse_oid_hex(argv[4], &oid, &argv[4]))
+			die("cannot parse oid '%s'", argv[4]);
+		test_parse_commit_in_graph(argv[2], argv[3], &oid);
+	} else if (!strcmp(argv[1], "get_commit_tree_in_graph")) {
+		struct object_id oid;
+		if (argc < 5)
+			die("not enough arguments");
+		if (parse_oid_hex(argv[4], &oid, &argv[4]))
+			die("cannot parse oid '%s'", argv[4]);
+		test_get_commit_tree_in_graph(argv[2], argv[3], &oid);
+	} else {
+		die("unrecognized '%s'", argv[1]);
+	}
+	return 0;
+}
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 805a45de9c..dafc91c240 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -29,6 +29,7 @@ static struct test_cmd cmds[] = {
 	{ "read-cache", cmd__read_cache },
 	{ "ref-store", cmd__ref_store },
 	{ "regex", cmd__regex },
+	{ "repository", cmd__repository },
 	{ "revision-walking", cmd__revision_walking },
 	{ "run-command", cmd__run_command },
 	{ "scrap-cache-tree", cmd__scrap_cache_tree },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 7116ddfb94..80cbcf0857 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -23,6 +23,7 @@ int cmd__prio_queue(int argc, const char **argv);
 int cmd__read_cache(int argc, const char **argv);
 int cmd__ref_store(int argc, const char **argv);
 int cmd__regex(int argc, const char **argv);
+int cmd__repository(int argc, const char **argv);
 int cmd__revision_walking(int argc, const char **argv);
 int cmd__run_command(int argc, const char **argv);
 int cmd__scrap_cache_tree(int argc, const char **argv);
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 5947de3d24..4f17d7701e 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -431,4 +431,39 @@ test_expect_success 'git fsck (checks commit-graph)' '
 	test_must_fail git fsck
 '
 
+test_expect_success 'setup non-the_repository tests' '
+	rm -rf repo &&
+	git init repo &&
+	test_commit -C repo one &&
+	test_commit -C repo two &&
+	git -C repo config core.commitGraph true &&
+	git -C repo rev-parse two | \
+		git -C repo commit-graph write --stdin-commits
+'
+
+test_expect_success 'parse_commit_in_graph works for non-the_repository' '
+	test-tool repository parse_commit_in_graph \
+		repo/.git repo "$(git -C repo rev-parse two)" >actual &&
+	echo $(git -C repo log --pretty="%ct" -1) \
+		$(git -C repo rev-parse one) >expect &&
+	test_cmp expect actual &&
+
+	test-tool repository parse_commit_in_graph \
+		repo/.git repo "$(git -C repo rev-parse one)" >actual &&
+	echo $(git -C repo log --pretty="%ct" -1 one) >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'get_commit_tree_in_graph works for non-the_repository' '
+	test-tool repository get_commit_tree_in_graph \
+		repo/.git repo "$(git -C repo rev-parse two)" >actual &&
+	echo $(git -C repo rev-parse two^{tree}) >expect &&
+	test_cmp expect actual &&
+
+	test-tool repository get_commit_tree_in_graph \
+		repo/.git repo "$(git -C repo rev-parse one)" >actual &&
+	echo $(git -C repo rev-parse one^{tree}) >expect &&
+	test_cmp expect actual
+'
+
 test_done