RE: [PATCH] Avoid rename/add conflict when contents are identical

>Due to this this (and maybe all the tests) need to depend on the
>SYMLINKS prereq.

Here's a third attempt with no use of symlinks in the test:

Skip the entire rename/add conflict case if the file added on the
other branch has the same contents as the file being renamed.  This
avoids giving the user an extra copy of the same file and presenting a
conflict that is confusing and pointless.

A simple test of this case has been added in
t/t3030-merge-recursive.sh.

Signed-off-by: Ken Schalk <ken.schalk@intel.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

merge-recursive.c

@@ -955,6 +955,12 @@ static int process_renames(struct merge_options *o,
 							ren1->pair->two : NULL,
 							branch1 == o->branch1 ?
 							NULL : ren1->pair->two, 1);
+			} else if ((dst_other.mode == ren1->pair->two->mode) &&
+				   sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
+				/* Added file on the other side
+				   identical to the file being
+				   renamed: clean merge */
+				update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 			} else if (!sha_eq(dst_other.sha1, null_sha1)) {
 				const char *new_path;
 				clean_merge = 0;

t/t3030-merge-recursive.sh

@@ -23,6 +23,8 @@ test_expect_success 'setup 1' '
 	git branch df-3 &&
 	git branch remove &&
 	git branch submod &&
+	git branch copy &&
+	git branch rename &&
 
 	echo hello >>a &&
 	cp a d/e &&
@@ -248,6 +250,22 @@ test_expect_success 'setup 7' '
 	git commit -m "make d/ a submodule"
 '
 
+test_expect_success 'setup 8' '
+	git checkout rename &&
+	git mv a e &&
+	git add e &&
+	test_tick &&
+	git commit -m "rename a->e"
+'
+
+test_expect_success 'setup 9' '
+	git checkout copy &&
+	cp a e &&
+	git add e &&
+	test_tick &&
+	git commit -m "copy a->e"
+'
+
 test_expect_success 'merge-recursive simple' '
 
 	rm -fr [abcd] &&
@@ -580,4 +598,21 @@ test_expect_failure 'merge-recursive simple w/submodule result' '
 	test_cmp expected actual
 '
 
+test_expect_success 'merge-recursive copy vs. rename' '
+	git checkout -f copy &&
+	git merge rename &&
+	( git ls-tree -r HEAD && git ls-files -s ) >actual &&
+	(
+		echo "100644 blob $o0	b"
+		echo "100644 blob $o0	c"
+		echo "100644 blob $o0	d/e"
+		echo "100644 blob $o0	e"
+		echo "100644 $o0 0	b"
+		echo "100644 $o0 0	c"
+		echo "100644 $o0 0	d/e"
+		echo "100644 $o0 0	e"
+	) >expected &&
+	test_cmp expected actual
+'
+
 test_done