4 files changed, 47 insertions, 3 deletions
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 2b78ba7fe4..699fe678cd 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -1640,7 +1640,7 @@ static void final(const char *final_pack_name, const char *curr_pack_name,
 	rename_tmp_packfile(&final_index_name, curr_index_name, &index_name,
 			    hash, "idx", 1);
 
-	if (do_fsck_object)
+	if (do_fsck_object && startup_info->have_repository)
 		packfile_store_load_pack(the_repository->objects->packfiles,
 					 final_index_name, 0);
 
@@ -2110,8 +2110,23 @@ int cmd_index_pack(int argc,
 	else
 		close(input_fd);
 
-	if (do_fsck_object && fsck_finish(&fsck_options))
-		die(_("fsck error in pack objects"));
+	if (do_fsck_object) {
+		/*
+		 * We cannot perform queued consistency checks when running
+		 * outside of a repository because those require us to read
+		 * from the object database, which is uninitialized.
+		 *
+		 * TODO: we may eventually set up an in-memory object database,
+		 * which would allow us to perform these queued checks.
+		 */
+		if (!startup_info->have_repository &&
+		    fsck_has_queued_checks(&fsck_options))
+			die(_("cannot perform queued object checks outside "
+			      "of a repository"));
+
+		if (fsck_finish(&fsck_options))
+			die(_("fsck error in pack objects"));
+	}
 
 	free(opts.anomaly);
 	free(objects);
diff --git a/fsck.c b/fsck.c
index 341e100d24..8e1565fe6d 100644
--- a/fsck.c
+++ b/fsck.c
@@ -1350,6 +1350,12 @@ int fsck_finish(struct fsck_options *options)
 	return ret;
 }
 
+bool fsck_has_queued_checks(struct fsck_options *options)
+{
+	return !oidset_equal(&options->gitmodules_found, &options->gitmodules_done) ||
+	       !oidset_equal(&options->gitattributes_found, &options->gitattributes_done);
+}
+
 void fsck_options_clear(struct fsck_options *options)
 {
 	free(options->msg_type);
diff --git a/fsck.h b/fsck.h
index cb6ef32f4f..336917c045 100644
--- a/fsck.h
+++ b/fsck.h
@@ -249,6 +249,13 @@ int fsck_tag_standalone(const struct object_id *oid, const char *buffer,
 int fsck_finish(struct fsck_options *options);
 
 /*
+ * Check whether there are any checks that have been queued up and that still
+ * need to be run. Returns `false` iff `fsck_finish()` wouldn't perform any
+ * actions, `true` otherwise.
+ */
+bool fsck_has_queued_checks(struct fsck_options *options);
+
+/*
  * Clear the fsck_options struct, freeing any allocated memory.
  */
 void fsck_options_clear(struct fsck_options *options);
diff --git a/t/t5302-pack-index.sh b/t/t5302-pack-index.sh
index 413c99274c..9697448cb2 100755
--- a/t/t5302-pack-index.sh
+++ b/t/t5302-pack-index.sh
@@ -293,4 +293,20 @@ test_expect_success 'too-large packs report the breach' '
 	grep "maximum allowed size (20 bytes)" err
 '
 
+# git-index-pack(1) uses the default hash algorithm outside of the repository,
+# and it has no way to tell it otherwise. So we can only run this test with the
+# default hash algorithm, as it would otherwise fail to parse the tree.
+test_expect_success DEFAULT_HASH_ALGORITHM 'index-pack --fsck-objects outside of a repo' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		printf "100644 blob $(test_oid 001)\t.gitattributes\n" >tree &&
+		git mktree --missing <tree >tree-oid &&
+		git pack-objects <tree-oid pack &&
+		test_must_fail nongit git index-pack --fsck-objects "$(pwd)"/pack-*.pack 2>err &&
+		test_grep "cannot perform queued object checks outside of a repository" err
+	)
+'
+
 test_done