t9350: point out that refs are not updated correctly

This happens only when the corresponding commits are not exported in
the current fast-export run. This can happen either when the relevant
commit is already marked, or when the commit is explicitly marked
as UNINTERESTING with a negative ref by another argument.

This breaks fast-export basec remote helpers.

Signed-off-by: Sverre Rabbelier <[email protected]>

Author: SRabbelier

t/t9350-fast-export.sh

@@ -540,4 +540,15 @@ test_expect_success 'when using -C, do not declare copy when source of copy is a
 	test_cmp expected actual
 '
 
+cat > expected << EOF
+reset refs/heads/master
+from $(git rev-parse master)
+
+EOF
+
+test_expect_failure 'refs are updated even if no commits need to be exported' '
+	git fast-export master..master > actual &&
+	test_cmp expected actual
+'
+
 test_done