[PATCH] merge-recursive: cause a conflict if file mode does not match

[Clemens Buchacher <drizzd@aon.at>]

Previously, mismatching file modes would be auto-merged by picking the
mode in the remote tree.

This also fixes a bug which caused merge-recursive to fail if the merged
files were empty.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
---

Hi Dscho,

Your patch certainly fixes a bug in git-merge-file. It does not fix the bug in
git-merge-recursive, however. The test script also fails with your patch.

On Thu, Mar 13, 2008 at 04:19:35PM +0100, Johannes Schindelin wrote:
> On Sat, Mar 08, 2008 at 06:17:26PM +0100, Clemens Buchacher wrote:
> > One could argue that it would be better to mark the mismatching 
> > permissions as a conflict.
> 
> Right you are.  Your whole "it still is xdl_merge()s fault" point was just 
> contradicted by your own analysis.  Calling xdl_merge() when the sha1 does 
> _not_ differ is _a mistake_.  _That_ is the bug.

Alright, fixed in the appended patch.

Regards,
Clemens

 merge-recursive.c          |    9 +++++++--
 t/t6031-merge-recursive.sh |   23 +++++++++++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100755 t/t6031-merge-recursive.sh

diff --git a/merge-recursive.c b/merge-recursive.c
index 34e3167..01918a7 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1028,9 +1028,14 @@ static struct merge_file_info merge_file(struct diff_filespec *o,
 		if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
 			result.merge = 1;
 
-		result.mode = a->mode == o->mode ? b->mode: a->mode;
+		if (!o->mode) {
+			if (a->mode != b->mode)
+				result.clean = 0;
+			result.mode = b->mode;
+		} else
+			result.mode = a->mode == o->mode ? b->mode: a->mode;
 
-		if (sha_eq(a->sha1, o->sha1))
+		if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, o->sha1))
 			hashcpy(result.sha, b->sha1);
 		else if (sha_eq(b->sha1, o->sha1))
 			hashcpy(result.sha, a->sha1);
diff --git a/t/t6031-merge-recursive.sh b/t/t6031-merge-recursive.sh
new file mode 100755
index 0000000..7ea371e
--- /dev/null
+++ b/t/t6031-merge-recursive.sh
@@ -0,0 +1,23 @@
+#!/bin/sh
+
+test_description='merge-recursive corner cases'
+. ./test-lib.sh
+
+test_expect_success 'merge empty files with different permission flags' '
+	: >dummy &&
+	git add dummy &&
+	git commit -m "initial commit" &&
+	git checkout -b a master &&
+	: >a &&
+	git add a &&
+	git commit -m "branch a" &&
+	git checkout -b b master &&
+	: >a &&
+	chmod +x a &&
+	git add a &&
+	git commit -m "branch b" &&
+	git checkout master &&
+	! (git merge-recursive master -- a b || test $? -ne 1)
+'
+
+test_done
-- 
1.5.4.4.2.gd2fe