[PATCH v2 5/8] repack: follow kept packs when omitting cruft from the MIDX

@@ -476,9 +476,11 @@ int cmd_repack(int argc,
 	show_progress = !po_args.quiet && isatty(2);
 
 	strvec_push(&cmd.args, "--keep-true-parents");
-	for (i = 0; i < keep_pack_list.nr; i++)
-		strvec_pushf(&cmd.args, "--keep-pack=%s",
-			     keep_pack_list.items[i].string);
+	/* Geometric follow walks exclude these packs through stdin instead. */
+	if (!(geometry.split_factor && !midx_must_contain_cruft))
+		for (i = 0; i < keep_pack_list.nr; i++)
+			strvec_pushf(&cmd.args, "--keep-pack=%s",
+				     keep_pack_list.items[i].string);
 	strvec_push(&cmd.args, "--non-empty");
 	if (!geometry.split_factor) {
 		/*

@@ -593,6 +595,29 @@ int cmd_repack(int argc,
 
 			fprintf(in, "%c%s\n", marker, basename);
 		}
+		if (!midx_must_contain_cruft) {
+			struct strbuf buf = STRBUF_INIT;
+
+			for_each_string_list_item(item, &existing.kept_packs) {
+				char marker = '^';
+
+				strbuf_reset(&buf);
+				strbuf_addf(&buf, "%s.pack", item->string);
+
+				if (po_args.pack_kept_objects &&
+				    !string_list_has_string(&keep_pack_list,
+							    buf.buf))
+					continue;
+
+				/* Exclusions override any inclusion above. */
+				if (!string_list_has_string(&existing.midx_packs,
+							    buf.buf))
+					marker = '!';
+
+				fprintf(in, "%c%s\n", marker, buf.buf);
+			}
+			strbuf_release(&buf);
+		}
 		fclose(in);
 	}
 

@@ -197,6 +197,7 @@ static void midx_included_packs(struct string_list *include,
 	}
 
 	if (opts->midx_must_contain_cruft ||
+	    (!geometry->split_factor && existing->kept_packs.nr) ||
 	    midx_has_unknown_packs(include, geometry, existing)) {
 		/*
 		 * If there are one or more unknown pack(s) present (see

@@ -209,6 +210,10 @@ static void midx_included_packs(struct string_list *include,
 		 * reachability closure if the MIDX is bitmapped and one
 		 * or more of the bitmap's selected commits reaches a
 		 * once-cruft object that was later made reachable.
+		 *
+		 * Kept packs may also depend on cruft objects, since
+		 * they are included above without necessarily being
+		 * traversed by a non-geometric repack.
 		 */
 		for_each_string_list_item(item, &existing->cruft_packs) {
 			/*

@@ -798,6 +798,49 @@ test_expect_success 'incremental repack includes cruft for MIDX bitmaps' '
 	)
 '
 
+test_expect_success 'geometric repack follows kept packs to cruft objects' '
+	setup_cruft_exclude_tests kept-cruft &&
+	(
+		cd kept-cruft &&
+
+		# Put HEAD in a kept pack, while its parent is still in
+		# a cruft pack.
+		pack=$(echo "HEAD^..HEAD" | git pack-objects --revs $packdir/pack) &&
+		git prune-packed &&
+		GIT_TEST_MULTI_PACK_INDEX=0 \
+		git repack -d --geometric=2 --write-midx --write-bitmap-index \
+			--keep-pack=pack-$pack.pack &&
+
+		test-tool find-pack -c 1 HEAD &&
+		test-tool read-midx --show-objects $objdir >midx &&
+		cruft=$(ls $packdir/*.mtimes) &&
+		test_grep ! "$(basename "$cruft" .mtimes).idx" midx
+	)
+'
+
+test_expect_success 'full repack retains cruft pack in MIDX for unreachable kept objects' '
+	setup_cruft_exclude_tests unreachable-kept-cruft &&
+	(
+		cd unreachable-kept-cruft &&
+
+		pack=$(echo "HEAD^..HEAD" | git pack-objects --revs $packdir/pack) &&
+		touch $packdir/pack-$pack.keep &&
+
+		# Make the kept commit unreachable so that the full
+		# repack leaves its parent in a cruft pack.
+		git reset --hard one &&
+		git tag -d four &&
+		git reflog expire --all --expire=all &&
+
+		GIT_TEST_MULTI_PACK_INDEX=0 \
+		git repack -a --write-midx --write-bitmap-index &&
+
+		test-tool read-midx --show-objects $objdir >midx &&
+		cruft=$(ls $packdir/*.mtimes) &&
+		test_grep "$(basename "$cruft" .mtimes).idx" midx
+	)
+'
+
 test_expect_success 'repack --write-midx includes cruft when instructed' '
 	setup_cruft_exclude_tests exclude-cruft-when-instructed &&
 	(