[PATCH 4/7] merge-ort: capture and print ll-merge warnings in our preferred fashion

["Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com>]

From: Elijah Newren <newren@gmail.com>

Instead of immediately printing ll-merge warnings to stderr, we save
them in our output strbuf.  Besides allowing us to move these warnings
to a special file for --remerge-diff, this has two other benefits for
regular merges done by merge-ort:

  * The deferral of messages ensures we can print all messages about
    any given path together (merge-recursive was known to sometimes
    intersperse messages about other paths, particularly when renames
    were involved).

  * The deferral of messages means we can avoid printing spurious
    conflict messages when we just end up aborting due to local user
    modifications in the way.  (In contrast to merge-recursive.c which
    prematurely checks for local modifications in the way via
    unpack_trees() and gets the check wrong both in terms of false
    positives and false negatives relative to renames, merge-ort does
    not perform the local modifications in the way check until the
    checkout() step after the full merge has been computed.)

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-ort.c                | 11 ++++++++---
 t/t6404-recursive-merge.sh | 10 ++++++++--
 t/t6406-merge-attr.sh      | 10 ++++++++--
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/merge-ort.c b/merge-ort.c
index a9e69d9cbb0..831f8f3e049 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -1741,6 +1741,7 @@ static int merge_3way(struct merge_options *opt,
 	struct ll_merge_options ll_opts = {0};
 	char *base, *name1, *name2;
 	int merge_status;
+	struct strbuf warnings = STRBUF_INIT;
 
 	if (!opt->priv->attr_index.initialized)
 		initialize_attr_index(opt);
@@ -1781,10 +1782,14 @@ static int merge_3way(struct merge_options *opt,
 	read_mmblob(&src1, a);
 	read_mmblob(&src2, b);
 
-	merge_status = ll_merge(result_buf, path, &orig, base,
-				&src1, name1, &src2, name2,
-				&opt->priv->attr_index, &ll_opts);
+	merge_status = ll_merge_with_warnings(result_buf, &warnings, path,
+					      &orig, base,
+					      &src1, name1, &src2, name2,
+					      &opt->priv->attr_index, &ll_opts);
+	if (warnings.len > 0)
+		path_msg(opt, path, 0, "%s", warnings.buf);
 
+	strbuf_release(&warnings);
 	free(base);
 	free(name1);
 	free(name2);
diff --git a/t/t6404-recursive-merge.sh b/t/t6404-recursive-merge.sh
index eaf48e941e2..a986eec0420 100755
--- a/t/t6404-recursive-merge.sh
+++ b/t/t6404-recursive-merge.sh
@@ -108,8 +108,14 @@ test_expect_success 'refuse to merge binary files' '
 	printf "\0\0" >binary-file &&
 	git add binary-file &&
 	git commit -m binary2 &&
-	test_must_fail git merge F >merge.out 2>merge.err &&
-	grep "Cannot merge binary files: binary-file (HEAD vs. F)" merge.err
+	if test "$GIT_TEST_MERGE_ALGORITHM" = ort
+	then
+		test_must_fail git merge F >merge.out &&
+		grep "Cannot merge binary files: binary-file (HEAD vs. F)" merge.out
+	else
+		test_must_fail git merge F >merge.out 2>merge.err &&
+		grep "Cannot merge binary files: binary-file (HEAD vs. F)" merge.err
+	fi
 '
 
 test_expect_success 'mark rename/delete as unmerged' '
diff --git a/t/t6406-merge-attr.sh b/t/t6406-merge-attr.sh
index 84946458371..75a7994988a 100755
--- a/t/t6406-merge-attr.sh
+++ b/t/t6406-merge-attr.sh
@@ -221,8 +221,14 @@ test_expect_success 'binary files with union attribute' '
 	printf "two\0" >bin.txt &&
 	git commit -am two &&
 
-	test_must_fail git merge bin-main 2>stderr &&
-	grep -i "warning.*cannot merge.*HEAD vs. bin-main" stderr
+	if test "$GIT_TEST_MERGE_ALGORITHM" = ort
+	then
+		test_must_fail git merge bin-main >stdout &&
+		grep -i "warning.*cannot merge.*HEAD vs. bin-main" stdout
+	else
+		test_must_fail git merge bin-main 2>stderr &&
+		grep -i "warning.*cannot merge.*HEAD vs. bin-main" stderr
+	fi
 '
 
 test_done
-- 
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