Merge branch 'jn/merge-diff3-label'

* jn/merge-diff3-label:
  merge-recursive: add a label for ancestor
  cherry-pick, revert: add a label for ancestor
  revert: clarify label on conflict hunks
  compat: add mempcpy()
  checkout -m --conflict=diff3: add a label for ancestor
  merge_trees(): add ancestor label parameter for diff3-style output
  merge_file(): add comment explaining behavior wrt conflict style
  checkout --conflict=diff3: add a label for ancestor
  ll_merge(): add ancestor label parameter for diff3-style output
  merge-file --diff3: add a label for ancestor
  xdl_merge(): move file1 and file2 labels to xmparam structure
  xdl_merge(): add optional ancestor label to diff3-style output
  tests: document cherry-pick behavior in face of conflicts
  tests: document format of conflicts from checkout -m

Conflicts:
	builtin/revert.c

1 files changed, 198 insertions, 0 deletions

diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
new file mode 100644
index 0000000000..e25cf8039a
--- /dev/null
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -0,0 +1,198 @@
+#!/bin/sh
+
+test_description='test cherry-pick and revert with conflicts
+
+  -
+  + picked: rewrites foo to c
+  + base: rewrites foo to b
+  + initial: writes foo as a, unrelated as unrelated
+
+'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+
+	echo unrelated >unrelated &&
+	git add unrelated &&
+	test_commit initial foo a &&
+	test_commit base foo b &&
+	test_commit picked foo c &&
+	git config advice.detachedhead false
+
+'
+
+test_expect_success 'failed cherry-pick does not advance HEAD' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	head=$(git rev-parse HEAD) &&
+	test_must_fail git cherry-pick picked &&
+	newhead=$(git rev-parse HEAD) &&
+
+	test "$head" = "$newhead"
+'
+
+test_expect_success 'failed cherry-pick produces dirty index' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	test_must_fail git cherry-pick picked &&
+
+	test_must_fail git update-index --refresh -q &&
+	test_must_fail git diff-index --exit-code HEAD
+'
+
+test_expect_success 'failed cherry-pick registers participants in index' '
+
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+	{
+		git checkout base -- foo &&
+		git ls-files --stage foo &&
+		git checkout initial -- foo &&
+		git ls-files --stage foo &&
+		git checkout picked -- foo &&
+		git ls-files --stage foo
+	} > stages &&
+	sed "
+		1 s/ 0	/ 1	/
+		2 s/ 0	/ 2	/
+		3 s/ 0	/ 3	/
+	" < stages > expected &&
+	git checkout -f initial^0 &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	test_must_fail git cherry-pick picked &&
+	git ls-files --stage --unmerged > actual &&
+
+	test_cmp expected actual
+'
+
+test_expect_success 'failed cherry-pick describes conflict in work tree' '
+
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+	cat <<-EOF > expected &&
+	<<<<<<< HEAD
+	a
+	=======
+	c
+	>>>>>>> objid picked
+	EOF
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	test_must_fail git cherry-pick picked &&
+
+	sed "s/[a-f0-9]*\.\.\./objid/" foo > actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'diff3 -m style' '
+
+	git config merge.conflictstyle diff3 &&
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+	cat <<-EOF > expected &&
+	<<<<<<< HEAD
+	a
+	||||||| parent of objid picked
+	b
+	=======
+	c
+	>>>>>>> objid picked
+	EOF
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	test_must_fail git cherry-pick picked &&
+
+	sed "s/[a-f0-9]*\.\.\./objid/" foo > actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'revert also handles conflicts sanely' '
+
+	git config --unset merge.conflictstyle &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+	cat <<-EOF > expected &&
+	<<<<<<< HEAD
+	a
+	=======
+	b
+	>>>>>>> parent of objid picked
+	EOF
+	{
+		git checkout picked -- foo &&
+		git ls-files --stage foo &&
+		git checkout initial -- foo &&
+		git ls-files --stage foo &&
+		git checkout base -- foo &&
+		git ls-files --stage foo
+	} > stages &&
+	sed "
+		1 s/ 0	/ 1	/
+		2 s/ 0	/ 2	/
+		3 s/ 0	/ 3	/
+	" < stages > expected-stages &&
+	git checkout -f initial^0 &&
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	head=$(git rev-parse HEAD) &&
+	test_must_fail git revert picked &&
+	newhead=$(git rev-parse HEAD) &&
+	git ls-files --stage --unmerged > actual-stages &&
+
+	test "$head" = "$newhead" &&
+	test_must_fail git update-index --refresh -q &&
+	test_must_fail git diff-index --exit-code HEAD &&
+	test_cmp expected-stages actual-stages &&
+	sed "s/[a-f0-9]*\.\.\./objid/" foo > actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'revert conflict, diff3 -m style' '
+	git config merge.conflictstyle diff3 &&
+	git checkout -f initial^0 &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x &&
+	cat <<-EOF > expected &&
+	<<<<<<< HEAD
+	a
+	||||||| objid picked
+	c
+	=======
+	b
+	>>>>>>> parent of objid picked
+	EOF
+
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD &&
+
+	test_must_fail git revert picked &&
+
+	sed "s/[a-f0-9]*\.\.\./objid/" foo > actual &&
+	test_cmp expected actual
+'
+
+test_done