Merge branch 'ps/pack-concat-wo-backfill' into next

"git pack-objects --stdin-packs" with "--exclude-promisor-objects"
fetched objects that are promised, which was not wanted.  This has
been fixed.

* ps/pack-concat-wo-backfill:
  builtin/pack-objects: don't fetch objects when merging packs

Author: gitster

builtin/pack-objects.c

@@ -3924,8 +3924,16 @@ static void add_unreachable_loose_objects(struct rev_info *revs);
 
 static void read_stdin_packs(enum stdin_packs_mode mode, int rev_list_unpacked)
 {
+	int prev_fetch_if_missing = fetch_if_missing;
 	struct rev_info revs;
 
+	/*
+	 * The revision walk may hit objects that are promised, only. As the
+	 * walk is best-effort though we don't want to perform backfill fetches
+	 * for them.
+	 */
+	fetch_if_missing = 0;
+
 	repo_init_revisions(the_repository, &revs, NULL);
 	/*
 	 * Use a revision walk to fill in the namehash of objects in the include
@@ -3961,6 +3969,8 @@ static void read_stdin_packs(enum stdin_packs_mode mode, int rev_list_unpacked)
 			   stdin_packs_found_nr);
 	trace2_data_intmax("pack-objects", the_repository, "stdin_packs_hints",
 			   stdin_packs_hints_nr);
+
+	fetch_if_missing = prev_fetch_if_missing;
 }
 
 static void add_cruft_object_entry(const struct object_id *oid, enum object_type type,

t/t5331-pack-objects-stdin.sh

@@ -358,6 +358,24 @@ test_expect_success '--stdin-packs with promisors' '
 	)
 '
 
+test_expect_success '--stdin-packs does not perform backfill fetch' '
+	test_when_finished "rm -rf remote client" &&
+
+	git init remote &&
+	test_commit_bulk -C remote 10 &&
+	git -C remote config set --local uploadpack.allowfilter 1 &&
+	git -C remote config set --local uploadpack.allowanysha1inwant 1 &&
+
+	git clone --filter=tree:0 "file://$(pwd)/remote" client &&
+	(
+		cd client &&
+		ls .git/objects/pack/*.promisor | sed "s|.*/||; s/\.promisor$/.pack/" >packs &&
+		test_line_count -gt 1 packs &&
+		GIT_TRACE2_EVENT="$(pwd)/event.log" git pack-objects --stdin-packs pack <packs &&
+		test_grep ! "\"event\":\"child_start\"" event.log
+	)
+'
+
 stdin_packs__follow_with_only () {
 	rm -fr stdin_packs__follow_with_only &&
 	git init stdin_packs__follow_with_only &&