merge-tree: provide easy access to `ls-files -u` style info

Much like `git merge` updates the index with information of the form
    (mode, oid, stage, name)
provide this output for conflicted files for merge-tree as well.
Provide a --name-only option for users to exclude the mode, oid, and
stage and only get the list of conflicted filenames.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 24 insertions, 2 deletions

diff --git a/t/t4301-merge-tree-write-tree.sh b/t/t4301-merge-tree-write-tree.sh
index 8e6dba4428..0ec5f0d3f7 100755
--- a/t/t4301-merge-tree-write-tree.sh
+++ b/t/t4301-merge-tree-write-tree.sh
@@ -65,6 +65,7 @@ test_expect_success 'Content merge and a few conflicts' '
 	expected_tree=$(git rev-parse AUTO_MERGE) &&
 
 	# We will redo the merge, while we are still in a conflicted state!
+	git ls-files -u >conflicted-file-info &&
 	test_when_finished "git reset --hard" &&
 
 	test_expect_code 1 git merge-tree --write-tree side1 side2 >RESULT &&
@@ -108,7 +109,7 @@ anonymize_hash() {
 }
 
 test_expect_success 'test conflict notices and such' '
-	test_expect_code 1 git merge-tree --write-tree side1 side2 >out &&
+	test_expect_code 1 git merge-tree --write-tree --name-only side1 side2 >out &&
 	anonymize_hash out >actual &&
 
 	# Expected results:
@@ -143,7 +144,7 @@ do
 done
 
 test_expect_success 'Just the conflicted files without the messages' '
-	test_expect_code 1 git merge-tree --write-tree --no-messages side1 side2 >out &&
+	test_expect_code 1 git merge-tree --write-tree --no-messages --name-only side1 side2 >out &&
 	anonymize_hash out >actual &&
 
 	test_write_lines HASH greeting whatever~side1 >expect &&
@@ -151,4 +152,25 @@ test_expect_success 'Just the conflicted files without the messages' '
 	test_cmp expect actual
 '
 
+test_expect_success 'Check conflicted oids and modes without messages' '
+	test_expect_code 1 git merge-tree --write-tree --no-messages side1 side2 >out &&
+	anonymize_hash out >actual &&
+
+	# Compare the basic output format
+	q_to_tab >expect <<-\EOF &&
+	HASH
+	100644 HASH 1Qgreeting
+	100644 HASH 2Qgreeting
+	100644 HASH 3Qgreeting
+	100644 HASH 1Qwhatever~side1
+	100644 HASH 2Qwhatever~side1
+	EOF
+
+	test_cmp expect actual &&
+
+	# Check the actual hashes against the `ls-files -u` output too
+	tail -n +2 out | sed -e s/side1/HEAD/ >actual &&
+	test_cmp conflicted-file-info actual
+'
+
 test_done