merge-tree: don't print entries that match "local"

The documentation says:

	the output from the command omits entries that match the
	<branch1> tree.

But currently "added in branch1" and "removed in branch1" (both while
unchanged in branch2) do print output.  Change this so that the
behaviour matches the documentation.

Signed-off-by: John Keeping <john@keeping.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/merge-tree.c

@@ -155,6 +155,11 @@ static int same_entry(struct name_entry *a, struct name_entry *b)
 		a->mode == b->mode;
 }
 
+static int both_empty(struct name_entry *a, struct name_entry *b)
+{
+	return !(a->sha1 || b->sha1);
+}
+
 static struct merge_list *create_entry(unsigned stage, unsigned mode, const unsigned char *sha1, const char *path)
 {
 	struct merge_list *res = xcalloc(1, sizeof(*res));
@@ -297,13 +302,10 @@ static void unresolved(const struct traverse_info *info, struct name_entry n[3])
 static int threeway_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *entry, struct traverse_info *info)
 {
 	/* Same in both? */
-	if (same_entry(entry+1, entry+2)) {
-		if (entry[0].sha1) {
-			/* Modified identically */
-			resolve(info, NULL, entry+1);
-			return mask;
-		}
-		/* "Both added the same" is left unresolved */
+	if (same_entry(entry+1, entry+2) || both_empty(entry+0, entry+2)) {
+		/* Modified, added or removed identically */
+		resolve(info, NULL, entry+1);
+		return mask;
 	}
 
 	if (same_entry(entry+0, entry+1)) {
@@ -319,12 +321,10 @@ static int threeway_callback(int n, unsigned long mask, unsigned long dirmask, s
 		 */
 	}
 
-	if (same_entry(entry+0, entry+2)) {
-		if (entry[1].sha1 && !S_ISDIR(entry[1].mode)) {
-			/* We modified, they did not touch -- take ours */
-			resolve(info, NULL, entry+1);
-			return mask;
-		}
+	if (same_entry(entry+0, entry+2) || both_empty(entry+0, entry+2)) {
+		/* We added, modified or removed, they did not touch -- take ours */
+		resolve(info, NULL, entry+1);
+		return mask;
 	}
 
 	unresolved(info, entry);

t/t4300-merge-tree.sh

@@ -26,8 +26,6 @@ EXPECTED
 
 test_expect_success 'file add !A, B' '
 	cat >expected <<\EXPECTED &&
-added in local
-  our    100644 43d5a8ed6ef6c00ff775008633f95787d088285d ONE
 EXPECTED
 
 	git reset --hard initial &&
@@ -38,9 +36,6 @@ EXPECTED
 
 test_expect_success 'file add A, B (same)' '
 	cat >expected <<\EXPECTED &&
-added in both
-  our    100644 43d5a8ed6ef6c00ff775008633f95787d088285d ONE
-  their  100644 43d5a8ed6ef6c00ff775008633f95787d088285d ONE
 EXPECTED
 
 	git reset --hard initial &&
@@ -181,9 +176,6 @@ AAA" &&
 
 test_expect_success 'file remove A, !B' '
 	cat >expected <<\EXPECTED &&
-removed in local
-  base   100644 43d5a8ed6ef6c00ff775008633f95787d088285d ONE
-  their  100644 43d5a8ed6ef6c00ff775008633f95787d088285d ONE
 EXPECTED
 
 	git reset --hard initial &&
@@ -283,8 +275,6 @@ test_expect_success 'turn tree to file' '
 	test_commit "make-file" "dir" "CCC" &&
 	git merge-tree add-tree add-another-tree make-file >actual &&
 	cat >expect <<-\EOF &&
-	added in local
-	  our    100644 ba629238ca89489f2b350e196ca445e09d8bb834 dir/another
 	removed in remote
 	  base   100644 43d5a8ed6ef6c00ff775008633f95787d088285d dir/path
 	  our    100644 43d5a8ed6ef6c00ff775008633f95787d088285d dir/path