[PATCH v6 p1.1 01/14] fast-export: avoid importing blob marks

[Felipe Contreras <felipe.contreras@gmail.com>]

We want to be able to import, and then export, using the same marks, so
that we don't push things that the other side already received.

Unfortunately, fast-export doesn't store blobs in the marks, but
fast-import does. This creates a mismatch when fast export is reusing a
mark that was previously stored by fast-import.

There is no point in one tool saving blobs, and the other not, but for
now let's just check in fast-export that the objects are indeed commits.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
---
 builtin/fast-export.c  |  4 ++++
 t/t9350-fast-export.sh | 14 ++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 12220ad..9b70ec1 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -614,6 +614,10 @@ static void import_marks(char *input_file)
 		if (object->flags & SHOWN)
 			error("Object %s already has a mark", sha1_to_hex(sha1));
 
+		if (object->type != OBJ_COMMIT)
+			/* only commits */
+			continue;
+
 		mark_object(object, mark);
 		if (last_idnum < mark)
 			last_idnum = mark;
diff --git a/t/t9350-fast-export.sh b/t/t9350-fast-export.sh
index 3e821f9..5948b65 100755
--- a/t/t9350-fast-export.sh
+++ b/t/t9350-fast-export.sh
@@ -440,4 +440,18 @@ test_expect_success 'fast-export quotes pathnames' '
 	)
 '
 
+test_expect_success 'test bidirectionality' '
+	>marks-cur &&
+	>marks-new &&
+	git init marks-test &&
+	git fast-export --export-marks=marks-cur --import-marks=marks-cur --branches | \
+	git --git-dir=marks-test/.git fast-import --export-marks=marks-new --import-marks=marks-new &&
+	(cd marks-test &&
+	git reset --hard &&
+	echo Wohlauf > file &&
+	git commit -a -m "back in time") &&
+	git --git-dir=marks-test/.git fast-export --export-marks=marks-new --import-marks=marks-new --branches | \
+	git fast-import --export-marks=marks-cur --import-marks=marks-cur
+'
+
 test_done
-- 
1.8.0