Merge branch 'xy/format-patch-base'

"git format-patch" learned a new "--base" option to record what
(public, well-known) commit the original series was built on in
its output.

* xy/format-patch-base:
  format-patch: introduce format.useAutoBase configuration
  format-patch: introduce --base=auto option
  format-patch: add '--base' option to record base tree info
  patch-ids: make commit_patch_id() a public helper function

1 files changed, 105 insertions, 0 deletions

diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index eed2981..8049cad 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -1460,4 +1460,109 @@ test_expect_success 'format-patch -o overrides format.outputDirectory' '
 	test_path_is_dir patchset
 '
 
+test_expect_success 'format-patch --base' '
+	git checkout side &&
+	git format-patch --stdout --base=HEAD~3 -1 >patch &&
+	grep "^base-commit:" patch >actual &&
+	grep "^prerequisite-patch-id:" patch >>actual &&
+	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 &&
+	test_cmp expected actual
+'
+
+test_expect_success 'format-patch --base errors out when base commit is in revision list' '
+	test_must_fail git format-patch --base=HEAD -2 &&
+	test_must_fail git format-patch --base=HEAD~1 -2 &&
+	git format-patch --stdout --base=HEAD~2 -2 >patch &&
+	grep "^base-commit:" patch >actual &&
+	echo "base-commit: $(git rev-parse HEAD~2)" >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success 'format-patch --base errors out when base commit is not ancestor of revision list' '
+	# For history as below:
+	#
+	#    ---Q---P---Z---Y---*---X
+	#	 \             /
+	#	  ------------W
+	#
+	# If "format-patch Z..X" is given, P and Z can not be specified as the base commit
+	git checkout -b topic1 master &&
+	git rev-parse HEAD >commit-id-base &&
+	test_commit P &&
+	git rev-parse HEAD >commit-id-P &&
+	test_commit Z &&
+	git rev-parse HEAD >commit-id-Z &&
+	test_commit Y &&
+	git checkout -b topic2 master &&
+	test_commit W &&
+	git merge topic1 &&
+	test_commit X &&
+	test_must_fail git format-patch --base=$(cat commit-id-P) -3 &&
+	test_must_fail git format-patch --base=$(cat commit-id-Z) -3 &&
+	git format-patch --stdout --base=$(cat commit-id-base) -3 >patch &&
+	grep "^base-commit:" patch >actual &&
+	echo "base-commit: $(cat commit-id-base)" >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success 'format-patch --base=auto' '
+	git checkout -b upstream master &&
+	git checkout -b local upstream &&
+	git branch --set-upstream-to=upstream &&
+	test_commit N1 &&
+	test_commit N2 &&
+	git format-patch --stdout --base=auto -2 >patch &&
+	grep "^base-commit:" patch >actual &&
+	echo "base-commit: $(git rev-parse upstream)" >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success 'format-patch errors out when history involves criss-cross' '
+	# setup criss-cross history
+	#
+	#   B---M1---D
+	#  / \ /
+	# A   X
+	#  \ / \
+	#   C---M2---E
+	#
+	git checkout master &&
+	test_commit A &&
+	git checkout -b xb master &&
+	test_commit B &&
+	git checkout -b xc master &&
+	test_commit C &&
+	git checkout -b xbc xb -- &&
+	git merge xc &&
+	git checkout -b xcb xc -- &&
+	git branch --set-upstream-to=xbc &&
+	git merge xb &&
+	git checkout xbc &&
+	test_commit D &&
+	git checkout xcb &&
+	test_commit E &&
+	test_must_fail 	git format-patch --base=auto -1
+'
+
+test_expect_success 'format-patch format.useAutoBaseoption' '
+	test_when_finished "git config --unset format.useAutoBase" &&
+	git checkout local &&
+	git config format.useAutoBase true &&
+	git format-patch --stdout -1 >patch &&
+	grep "^base-commit:" patch >actual &&
+	echo "base-commit: $(git rev-parse upstream)" >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success 'format-patch --base overrides format.useAutoBase' '
+	test_when_finished "git config --unset format.useAutoBase" &&
+	git config format.useAutoBase true &&
+	git format-patch --stdout --base=HEAD~1 -1 >patch &&
+	grep "^base-commit:" patch >actual &&
+	echo "base-commit: $(git rev-parse HEAD~1)" >expected &&
+	test_cmp expected actual
+'
+
 test_done