diff --git a/diff.c b/diff.c
index afb629e613..5a71489a47 100644
--- a/diff.c
+++ b/diff.c
@@ -2217,7 +2217,7 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 
 		xpp.flags = XDF_NEED_MINIMAL;
 		xecfg.ctxlen = 3;
-		xecfg.flags = 3;
+		xecfg.flags = XDL_EMIT_FUNCNAMES;
 		ecb.outf = xdiff_outf;
 		ecb.priv = &data;
 		xdl_diff(&mf1, &mf2, &xpp, &xecfg, &ecb);
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index ac2fde773d..4795872a77 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -21,15 +21,15 @@ test_expect_success setup '
 	for i in D E F; do echo "$i"; done >>file &&
 	git update-index file &&
 	git commit -m "Side change #2" &&
-	git tag C1 &&
+	git tag C2 &&
 
 	for i in 5 6 1 2 3 A 4 B C 7 8 9 10 D E F; do echo "$i"; done >file &&
 	git update-index file &&
 	git commit -m "Side change #3" &&
 
 	git checkout master &&
-	git diff-tree -p C1 | git apply --index &&
-	git commit -m "Master accepts moral equivalent of #1"
+	git diff-tree -p C2 | git apply --index &&
+	git commit -m "Master accepts moral equivalent of #2"
 
 '