Merge branch 'sb/format-patch-base-patch-id-fix'

The "--base" option of "format-patch" computed the patch-ids for
prerequisite patches in an unstable way, which has been updated to
compute in a way that is compatible with "git patch-id --stable".

* sb/format-patch-base-patch-id-fix:
  format-patch: make --base patch-id output stable
  format-patch: inform user that patch-id generation is unstable

1 files changed, 29 insertions, 3 deletions

diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index b6e2fdbc44..7a5833a4b2 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -36,8 +36,27 @@ test_expect_success setup '
 	git checkout master &&
 	git diff-tree -p C2 | git apply --index &&
 	test_tick &&
-	git commit -m "Master accepts moral equivalent of #2"
+	git commit -m "Master accepts moral equivalent of #2" &&
 
+	git checkout side &&
+	git checkout -b patchid &&
+	for i in 5 6 1 2 3 A 4 B C 7 8 9 10 D E F; do echo "$i"; done >file2 &&
+	for i in 1 2 3 A 4 B C 7 8 9 10 D E F 5 6; do echo "$i"; done >file3 &&
+	for i in 8 9 10; do echo "$i"; done >file &&
+	git add file file2 file3 &&
+	test_tick &&
+	git commit -m "patchid 1" &&
+	for i in 4 A B 7 8 9 10; do echo "$i"; done >file2 &&
+	for i in 8 9 10 5 6; do echo "$i"; done >file3 &&
+	git add file2 file3 &&
+	test_tick &&
+	git commit -m "patchid 2" &&
+	for i in 10 5 6; do echo "$i"; done >file &&
+	git add file &&
+	test_tick &&
+	git commit -m "patchid 3" &&
+
+	git checkout master
 '
 
 test_expect_success "format-patch --ignore-if-in-upstream" '
@@ -1559,7 +1578,7 @@ test_expect_success 'format-patch -o overrides format.outputDirectory' '
 '
 
 test_expect_success 'format-patch --base' '
-	git checkout side &&
+	git checkout patchid &&
 	git format-patch --stdout --base=HEAD~3 -1 | tail -n 7 >actual1 &&
 	git format-patch --stdout --base=HEAD~3 HEAD~.. | tail -n 7 >actual2 &&
 	echo >expected &&
@@ -1568,7 +1587,14 @@ test_expect_success 'format-patch --base' '
 	echo "prerequisite-patch-id: $(git show --patch HEAD~1 | git patch-id --stable | awk "{print \$1}")" >>expected &&
 	signature >> expected &&
 	test_cmp expected actual1 &&
-	test_cmp expected actual2
+	test_cmp expected actual2 &&
+	echo >fail &&
+	echo "base-commit: $(git rev-parse HEAD~3)" >>fail &&
+	echo "prerequisite-patch-id: $(git show --patch HEAD~2 | git patch-id --unstable | awk "{print \$1}")" >>fail &&
+	echo "prerequisite-patch-id: $(git show --patch HEAD~1 | git patch-id --unstable | awk "{print \$1}")" >>fail &&
+	signature >> fail &&
+	! test_cmp fail actual1 &&
+	! test_cmp fail actual2
 '
 
 test_expect_success 'format-patch --base errors out when base commit is in revision list' '