Merge branch 'ma/fast-export-skip-merge-fix'

"git fast-export" had a regression in v2.15.0 era where it skipped
some merge commits in certain cases, which has been corrected.

* ma/fast-export-skip-merge-fix:
  fast-export: fix regression skipping some merge-commits

builtin/fast-export.c

@@ -651,8 +651,11 @@ static void handle_tail(struct object_array *commits, struct rev_info *revs,
 	struct commit *commit;
 	while (commits->nr) {
 		commit = (struct commit *)object_array_pop(commits);
-		if (has_unshown_parent(commit))
+		if (has_unshown_parent(commit)) {
+			/* Queue again, to be handled later */
+			add_object_array(&commit->object, NULL, commits);
 			return;
+		}
 		handle_commit(commit, revs, paths_of_changed_objects);
 	}
 }

t/t9350-fast-export.sh

@@ -538,4 +538,22 @@ test_expect_success 'when using -C, do not declare copy when source of copy is a
 	test_cmp expected actual
 '
 
+test_expect_success 'merge commit gets exported with --import-marks' '
+	test_create_repo merging &&
+	(
+		cd merging &&
+		test_commit initial &&
+		git checkout -b topic &&
+		test_commit on-topic &&
+		git checkout master &&
+		test_commit on-master &&
+		test_tick &&
+		git merge --no-ff -m Yeah topic &&
+
+		echo ":1 $(git rev-parse HEAD^^)" >marks &&
+		git fast-export --import-marks=marks master >out &&
+		grep Yeah out
+	)
+'
+
 test_done