Merge branch 'ps/connectivity-optim'

The revision traversal API has been optimized by taking advantage
of the commit-graph, when available, to determine if a commit is
reachable from any of the existing refs.

* ps/connectivity-optim:
  revision: avoid hitting packfiles when commits are in commit-graph
  commit-graph: split out function to search commit position
  revision: stop retrieving reference twice
  connected: do not sort input revisions
  revision: separate walk and unsorted flags

9 files changed, 127 insertions, 46 deletions

diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 24569b06d1..b7bd27e171 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -968,6 +968,11 @@ list of the missing objects.  Object IDs are prefixed with a ``?'' character.
 	objects.
 endif::git-rev-list[]
 
+--unsorted-input::
+	Show commits in the order they were given on the command line instead
+	of sorting them in reverse chronological order by commit time. Cannot
+	be combined with `--no-walk` or `--no-walk=sorted`.
+
 --no-walk[=(sorted|unsorted)]::
 	Only show the given commits, but do not traverse their ancestors.
 	This has no effect if a range is specified. If the argument
@@ -975,7 +980,8 @@ endif::git-rev-list[]
 	given on the command line. Otherwise (if `sorted` or no argument
 	was given), the commits are shown in reverse chronological order
 	by commit time.
-	Cannot be combined with `--graph`.
+	Cannot be combined with `--graph`. Cannot be combined with
+	`--unsorted-input` if `sorted` or no argument was given.
 
 --do-walk::
 	Overrides a previous `--no-walk`.
diff --git a/builtin/log.c b/builtin/log.c
index 3d7717ba5c..f75d87e8d7 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -637,7 +637,7 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 	repo_init_revisions(the_repository, &rev, prefix);
 	rev.diff = 1;
 	rev.always_show_header = 1;
-	rev.no_walk = REVISION_WALK_NO_WALK_SORTED;
+	rev.no_walk = 1;
 	rev.diffopt.stat_width = -1; 	/* Scale to real terminal size */
 
 	memset(&opt, 0, sizeof(opt));
diff --git a/builtin/revert.c b/builtin/revert.c
index 237f2f18d4..2e13660e4b 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -191,7 +191,8 @@ static int run_sequencer(int argc, const char **argv, struct replay_opts *opts)
 		struct setup_revision_opt s_r_opt;
 		opts->revs = xmalloc(sizeof(*opts->revs));
 		repo_init_revisions(the_repository, opts->revs, NULL);
-		opts->revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
+		opts->revs->no_walk = 1;
+		opts->revs->unsorted_input = 1;
 		if (argc < 2)
 			usage_with_options(usage_str, options);
 		if (!strcmp(argv[1], "-"))
diff --git a/commit-graph.c b/commit-graph.c
index 3860a0d847..00614acd65 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -723,7 +723,7 @@ void close_commit_graph(struct raw_object_store *o)
 	o->commit_graph = NULL;
 }
 
-static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
+static int bsearch_graph(struct commit_graph *g, const struct object_id *oid, uint32_t *pos)
 {
 	return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 			    g->chunk_oid_lookup, g->hash_len, pos);
@@ -864,26 +864,55 @@ static int fill_commit_in_graph(struct repository *r,
 	return 1;
 }
 
-static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
+static int search_commit_pos_in_graph(const struct object_id *id, struct commit_graph *g, uint32_t *pos)
+{
+	struct commit_graph *cur_g = g;
+	uint32_t lex_index;
+
+	while (cur_g && !bsearch_graph(cur_g, id, &lex_index))
+		cur_g = cur_g->base_graph;
+
+	if (cur_g) {
+		*pos = lex_index + cur_g->num_commits_in_base;
+		return 1;
+	}
+
+	return 0;
+}
+
+static int find_commit_pos_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 {
 	uint32_t graph_pos = commit_graph_position(item);
 	if (graph_pos != COMMIT_NOT_FROM_GRAPH) {
 		*pos = graph_pos;
 		return 1;
 	} else {
-		struct commit_graph *cur_g = g;
-		uint32_t lex_index;
+		return search_commit_pos_in_graph(&item->object.oid, g, pos);
+	}
+}
 
-		while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
-			cur_g = cur_g->base_graph;
+struct commit *lookup_commit_in_graph(struct repository *repo, const struct object_id *id)
+{
+	struct commit *commit;
+	uint32_t pos;
 
-		if (cur_g) {
-			*pos = lex_index + cur_g->num_commits_in_base;
-			return 1;
-		}
+	if (!repo->objects->commit_graph)
+		return NULL;
+	if (!search_commit_pos_in_graph(id, repo->objects->commit_graph, &pos))
+		return NULL;
+	if (!repo_has_object_file(repo, id))
+		return NULL;
 
-		return 0;
-	}
+	commit = lookup_commit(repo, id);
+	if (!commit)
+		return NULL;
+	if (commit->object.parsed)
+		return commit;
+
+	if (!fill_commit_in_graph(repo, commit, repo->objects->commit_graph, pos))
+		return NULL;
+
+	return commit;
 }
 
 static int parse_commit_in_graph_one(struct repository *r,
@@ -895,7 +924,7 @@ static int parse_commit_in_graph_one(struct repository *r,
 	if (item->object.parsed)
 		return 1;
 
-	if (find_commit_in_graph(item, g, &pos))
+	if (find_commit_pos_in_graph(item, g, &pos))
 		return fill_commit_in_graph(r, item, g, pos);
 
 	return 0;
@@ -921,7 +950,7 @@ void load_commit_graph_info(struct repository *r, struct commit *item)
 	uint32_t pos;
 	if (!prepare_commit_graph(r))
 		return;
-	if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
+	if (find_commit_pos_in_graph(item, r->objects->commit_graph, &pos))
 		fill_commit_graph_info(item, r->objects->commit_graph, pos);
 }
 
@@ -1091,9 +1120,9 @@ static int write_graph_chunk_data(struct hashfile *f,
 				edge_value += ctx->new_num_commits_in_base;
 			else if (ctx->new_base_graph) {
 				uint32_t pos;
-				if (find_commit_in_graph(parent->item,
-							 ctx->new_base_graph,
-							 &pos))
+				if (find_commit_pos_in_graph(parent->item,
+							     ctx->new_base_graph,
+							     &pos))
 					edge_value = pos;
 			}
 
@@ -1122,9 +1151,9 @@ static int write_graph_chunk_data(struct hashfile *f,
 				edge_value += ctx->new_num_commits_in_base;
 			else if (ctx->new_base_graph) {
 				uint32_t pos;
-				if (find_commit_in_graph(parent->item,
-							 ctx->new_base_graph,
-							 &pos))
+				if (find_commit_pos_in_graph(parent->item,
+							     ctx->new_base_graph,
+							     &pos))
 					edge_value = pos;
 			}
 
@@ -1235,9 +1264,9 @@ static int write_graph_chunk_extra_edges(struct hashfile *f,
 				edge_value += ctx->new_num_commits_in_base;
 			else if (ctx->new_base_graph) {
 				uint32_t pos;
-				if (find_commit_in_graph(parent->item,
-							 ctx->new_base_graph,
-							 &pos))
+				if (find_commit_pos_in_graph(parent->item,
+							     ctx->new_base_graph,
+							     &pos))
 					edge_value = pos;
 			}
 
diff --git a/commit-graph.h b/commit-graph.h
index 96c24fb577..04a94e1830 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -41,6 +41,14 @@ int open_commit_graph(const char *graph_file, int *fd, struct stat *st);
 int parse_commit_in_graph(struct repository *r, struct commit *item);
 
 /*
+ * Look up the given commit ID in the commit-graph. This will only return a
+ * commit if the ID exists both in the graph and in the object database such
+ * that we don't return commits whose object has been pruned. Otherwise, this
+ * function returns `NULL`.
+ */
+struct commit *lookup_commit_in_graph(struct repository *repo, const struct object_id *id);
+
+/*
  * It is possible that we loaded commit contents from the commit buffer,
  * but we also want to ensure the commit-graph content is correctly
  * checked and filled. Fill the graph_pos and generation members of
diff --git a/connected.c b/connected.c
index b18299fdf0..b5f9523a5f 100644
--- a/connected.c
+++ b/connected.c
@@ -106,6 +106,7 @@ no_promisor_pack_found:
 	if (opt->progress)
 		strvec_pushf(&rev_list.args, "--progress=%s",
 			     _("Checking connectivity"));
+	strvec_push(&rev_list.args, "--unsorted-input");
 
 	rev_list.git_cmd = 1;
 	rev_list.env = opt->env;
diff --git a/revision.c b/revision.c
index cddd0542a6..0dabb5a0bc 100644
--- a/revision.c
+++ b/revision.c
@@ -360,20 +360,18 @@ static struct object *get_reference(struct rev_info *revs, const char *name,
 				    unsigned int flags)
 {
 	struct object *object;
+	struct commit *commit;
 
 	/*
-	 * If the repository has commit graphs, repo_parse_commit() avoids
-	 * reading the object buffer, so use it whenever possible.
+	 * If the repository has commit graphs, we try to opportunistically
+	 * look up the object ID in those graphs. Like this, we can avoid
+	 * parsing commit data from disk.
 	 */
-	if (oid_object_info(revs->repo, oid, NULL) == OBJ_COMMIT) {
-		struct commit *c = lookup_commit(revs->repo, oid);
-		if (!repo_parse_commit(revs->repo, c))
-			object = (struct object *) c;
-		else
-			object = NULL;
-	} else {
+	commit = lookup_commit_in_graph(revs->repo, oid);
+	if (commit)
+		object = &commit->object;
+	else
 		object = parse_object(revs->repo, oid);
-	}
 
 	if (!object) {
 		if (revs->ignore_missing)
@@ -1534,7 +1532,7 @@ static int handle_one_ref(const char *path, const struct object_id *oid,
 
 	object = get_reference(cb->all_revs, path, oid, cb->all_flags);
 	add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
-	add_pending_oid(cb->all_revs, path, oid, cb->all_flags);
+	add_pending_object(cb->all_revs, object, path);
 	return 0;
 }
 
@@ -2256,6 +2254,10 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 	} else if (!strcmp(arg, "--author-date-order")) {
 		revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
 		revs->topo_order = 1;
+	} else if (!strcmp(arg, "--unsorted-input")) {
+		if (revs->no_walk)
+			die(_("--unsorted-input is incompatible with --no-walk"));
+		revs->unsorted_input = 1;
 	} else if (!strcmp(arg, "--early-output")) {
 		revs->early_output = 100;
 		revs->topo_order = 1;
@@ -2651,16 +2653,22 @@ static int handle_revision_pseudo_opt(const char *submodule,
 	} else if (!strcmp(arg, "--not")) {
 		*flags ^= UNINTERESTING | BOTTOM;
 	} else if (!strcmp(arg, "--no-walk")) {
-		revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
+		if (!revs->no_walk && revs->unsorted_input)
+			die(_("--no-walk is incompatible with --unsorted-input"));
+		revs->no_walk = 1;
 	} else if (skip_prefix(arg, "--no-walk=", &optarg)) {
+		if (!revs->no_walk && revs->unsorted_input)
+			die(_("--no-walk is incompatible with --unsorted-input"));
+
 		/*
 		 * Detached form ("--no-walk X" as opposed to "--no-walk=X")
 		 * not allowed, since the argument is optional.
 		 */
+		revs->no_walk = 1;
 		if (!strcmp(optarg, "sorted"))
-			revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
+			revs->unsorted_input = 0;
 		else if (!strcmp(optarg, "unsorted"))
-			revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
+			revs->unsorted_input = 1;
 		else
 			return error("invalid argument to --no-walk");
 	} else if (!strcmp(arg, "--do-walk")) {
@@ -3584,7 +3592,7 @@ int prepare_revision_walk(struct rev_info *revs)
 
 	if (!revs->reflog_info)
 		prepare_to_use_bloom_filter(revs);
-	if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
+	if (!revs->unsorted_input)
 		commit_list_sort_by_date(&revs->commits);
 	if (revs->no_walk)
 		return 0;
diff --git a/revision.h b/revision.h
index fbb068da9f..0c65a760ee 100644
--- a/revision.h
+++ b/revision.h
@@ -79,10 +79,6 @@ struct rev_cmdline_info {
 	} *rev;
 };
 
-#define REVISION_WALK_WALK 0
-#define REVISION_WALK_NO_WALK_SORTED 1
-#define REVISION_WALK_NO_WALK_UNSORTED 2
-
 struct oidset;
 struct topo_walk_info;
 
@@ -129,7 +125,8 @@ struct rev_info {
 	/* Traversal flags */
 	unsigned int	dense:1,
 			prune:1,
-			no_walk:2,
+			no_walk:1,
+			unsorted_input:1,
 			remove_empty_trees:1,
 			simplify_history:1,
 			show_pulls:1,
diff --git a/t/t6000-rev-list-misc.sh b/t/t6000-rev-list-misc.sh
index 12def7bcbf..ef849e5bc8 100755
--- a/t/t6000-rev-list-misc.sh
+++ b/t/t6000-rev-list-misc.sh
@@ -169,4 +169,35 @@ test_expect_success 'rev-list --count --objects' '
 	test_line_count = $count actual
 '
 
+test_expect_success 'rev-list --unsorted-input results in different sorting' '
+	git rev-list --unsorted-input HEAD HEAD~ >first &&
+	git rev-list --unsorted-input HEAD~ HEAD >second &&
+	! test_cmp first second &&
+	sort first >first.sorted &&
+	sort second >second.sorted &&
+	test_cmp first.sorted second.sorted
+'
+
+test_expect_success 'rev-list --unsorted-input incompatible with --no-walk' '
+	cat >expect <<-EOF &&
+		fatal: --no-walk is incompatible with --unsorted-input
+	EOF
+	test_must_fail git rev-list --unsorted-input --no-walk HEAD 2>error &&
+	test_cmp expect error &&
+	test_must_fail git rev-list --unsorted-input --no-walk=sorted HEAD 2>error &&
+	test_cmp expect error &&
+	test_must_fail git rev-list --unsorted-input --no-walk=unsorted HEAD 2>error &&
+	test_cmp expect error &&
+
+	cat >expect <<-EOF &&
+		fatal: --unsorted-input is incompatible with --no-walk
+	EOF
+	test_must_fail git rev-list --no-walk --unsorted-input HEAD 2>error &&
+	test_cmp expect error &&
+	test_must_fail git rev-list --no-walk=sorted --unsorted-input HEAD 2>error &&
+	test_cmp expect error &&
+	test_must_fail git rev-list --no-walk=unsorted --unsorted-input HEAD 2>error &&
+	test_cmp expect error
+'
+
 test_done