format-patch: inform user that patch-id generation is unstable

I tried out 'git format-patch --base' with a set of commits that
modifies more than one file. It turns out that the way this command is
implemented it actually uses the unstable version of patch-id instead of
the stable version that's documented. When I tried to modify the
existing test to use 'git patch-id --stable' vs. 'git patch-id
--unstable' I found that it didn't matter, the test still passed.

Let's expand on the test here so it is a little more complicated and
then use that to show that the patch-id generation is actually unstable
vs. stable. Update the documentation as well.

Cc: Xiaolong Ye <xiaolong.ye@intel.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index 1af85d404f5191c18a8c587df06e7c0620066236..e8cc792e7f5d006a1e46b4f5acae9da1230fecbc 100644 (file)
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -583,7 +583,7 @@ of 'base commit' in topological order before the patches can be applied.
 The 'base commit' is shown as "base-commit: " followed by the 40-hex of
 the commit object name.  A 'prerequisite patch' is shown as
 "prerequisite-patch-id: " followed by the 40-hex 'patch id', which can
-be obtained by passing the patch through the `git patch-id --stable`
+be obtained by passing the patch through the `git patch-id --unstable`
 command.
 
 Imagine that on top of the public commit P, you applied well-known

diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index b6e2fdbc4410f1b8b04586f12bb8806e85a10e8d..e82c6c7d917762e82f1ee6bc5991f372f762b024 100755 (executable)
--- 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" '
@@ -1559,16 +1578,23 @@ 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 &&
        echo "base-commit: $(git rev-parse HEAD~3)" >>expected &&
-       echo "prerequisite-patch-id: $(git show --patch HEAD~2 | git patch-id --stable | awk "{print \$1}")" >>expected &&
-       echo "prerequisite-patch-id: $(git show --patch HEAD~1 | git patch-id --stable | awk "{print \$1}")" >>expected &&
+       echo "prerequisite-patch-id: $(git show --patch HEAD~2 | git patch-id --unstable | awk "{print \$1}")" >>expected &&
+       echo "prerequisite-patch-id: $(git show --patch HEAD~1 | git patch-id --unstable | 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 --stable | awk "{print \$1}")" >>fail &&
+       echo "prerequisite-patch-id: $(git show --patch HEAD~1 | git patch-id --stable | 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' '