Merge branch 'jk/union-merge-binary'

The "union" conflict resolution variant misbehaved when used with
binary merge driver.

* jk/union-merge-binary:
  ll_union_merge(): rename path_unused parameter
  ll_union_merge(): pass name labels to ll_xdl_merge()
  ll_binary_merge(): handle XDL_MERGE_FAVOR_UNION

Author: gitster

ll-merge.c

@@ -91,7 +91,9 @@ static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
 	 * With -Xtheirs or -Xours, we have cleanly merged;
 	 * otherwise we got a conflict.
 	 */
-	return (opts->variant ? 0 : 1);
+	return opts->variant == XDL_MERGE_FAVOR_OURS ||
+	       opts->variant == XDL_MERGE_FAVOR_THEIRS ?
+	       0 : 1;
 }
 
 static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
@@ -136,7 +138,7 @@ static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
 
 static int ll_union_merge(const struct ll_merge_driver *drv_unused,
 			  mmbuffer_t *result,
-			  const char *path_unused,
+			  const char *path,
 			  mmfile_t *orig, const char *orig_name,
 			  mmfile_t *src1, const char *name1,
 			  mmfile_t *src2, const char *name2,
@@ -148,8 +150,8 @@ static int ll_union_merge(const struct ll_merge_driver *drv_unused,
 	assert(opts);
 	o = *opts;
 	o.variant = XDL_MERGE_FAVOR_UNION;
-	return ll_xdl_merge(drv_unused, result, path_unused,
-			    orig, NULL, src1, NULL, src2, NULL,
+	return ll_xdl_merge(drv_unused, result, path,
+			    orig, orig_name, src1, name1, src2, name2,
 			    &o, marker_size);
 }
 

t/t6406-merge-attr.sh

@@ -207,4 +207,22 @@ test_expect_success 'custom merge does not lock index' '
 	git merge main
 '
 
+test_expect_success 'binary files with union attribute' '
+	git checkout -b bin-main &&
+	printf "base\0" >bin.txt &&
+	echo "bin.txt merge=union" >.gitattributes &&
+	git add bin.txt .gitattributes &&
+	git commit -m base &&
+
+	printf "one\0" >bin.txt &&
+	git commit -am one &&
+
+	git checkout -b bin-side HEAD^ &&
+	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
+'
+
 test_done