Merge branch 'jc/merge-symlink-ours-theirs' into maint

"git merge -Xours/-Xtheirs" learned to use our/their version when
resolving a conflicting updates to a symbolic link.

* jc/merge-symlink-ours-theirs:
  merge: teach -Xours/-Xtheirs to symbolic link merge

merge-recursive.c

@@ -1026,10 +1026,19 @@ static int merge_file_1(struct merge_options *o,
 						       &b->oid,
 						       !o->call_depth);
 		} else if (S_ISLNK(a->mode)) {
-			oidcpy(&result->oid, &a->oid);
-
-			if (!oid_eq(&a->oid, &b->oid))
-				result->clean = 0;
+			switch (o->recursive_variant) {
+			case MERGE_RECURSIVE_NORMAL:
+				oidcpy(&result->oid, &a->oid);
+				if (!oid_eq(&a->oid, &b->oid))
+					result->clean = 0;
+				break;
+			case MERGE_RECURSIVE_OURS:
+				oidcpy(&result->oid, &a->oid);
+				break;
+			case MERGE_RECURSIVE_THEIRS:
+				oidcpy(&result->oid, &b->oid);
+				break;
+			}
 		} else
 			die("BUG: unsupported object type in the tree");
 	}

t/t6037-merge-ours-theirs.sh

@@ -73,4 +73,36 @@ test_expect_success 'pull passes -X to underlying merge' '
 	git reset --hard master && test_must_fail git pull -s recursive -X bork . side
 '
 
+test_expect_success SYMLINKS 'symlink with -Xours/-Xtheirs' '
+	git reset --hard master &&
+	git checkout -b two master &&
+	ln -s target-zero link &&
+	git add link &&
+	git commit -m "add link pointing to zero" &&
+
+	ln -f -s target-two link &&
+	git commit -m "add link pointing to two" link &&
+
+	git checkout -b one HEAD^ &&
+	ln -f -s target-one link &&
+	git commit -m "add link pointing to one" link &&
+
+	# we expect symbolic links not to resolve automatically, of course
+	git checkout one^0 &&
+	test_must_fail git merge -s recursive two &&
+
+	# favor theirs to resolve to target-two?
+	git reset --hard &&
+	git checkout one^0 &&
+	git merge -s recursive -X theirs two &&
+	git diff --exit-code two HEAD link &&
+
+	# favor ours to resolve to target-one?
+	git reset --hard &&
+	git checkout one^0 &&
+	git merge -s recursive -X ours two &&
+	git diff --exit-code one HEAD link
+
+'
+
 test_done