@matheusbsbs / matheus-bagliano / commits / 751e165424

merge-ort: fix issue with dual rename and add/add conflict

There is code in both merge-recursive and merge-ort for avoiding doubly transitive renames (i.e. one side renames directory A/ -> B/, and the other side renames directory B/ -> C/), because this combination would otherwise make a mess for new files added to A/ on the first side and wondering which directory they end up in -- especially if there were even more renames such as the first side renaming C/ -> D/. In such cases, it just turns "off" directory rename detection for the higher order transitive cases. The testcases added in t6423 a couple commits ago are slightly different but similar in principle. They involve a similar case of paired renaming but instead of A/ -> B/ and B/ -> C/, the second side renames a leading directory of B/ to C/. And both sides add a new file somewhere under the directory that the other side will rename. While the new files added start within different directories and thus could logically end up within different directories, it is weird for a file on one side to end up where the other one started and not move along with it. So, let's just turn off directory rename detection in this case as well. Another way to look at this is that if the source name involved in a directory rename on one side is the target name of a directory rename operation for a file from the other side, then we avoid the doubly transitive rename. (More concretely, if a directory rename on side D wants to rename a file on side E from OLD_NAME -> NEW_NAME, and side D already had a file named NEW_NAME, and a directory rename on side E wants to rename side D's NEW_NAME -> NEWER_NAME, then we turn off the directory rename detection for NEW_NAME to prevent the NEW_NAME -> NEWER_NAME rename, and instead end up with an add/add conflict on NEW_NAME.) Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Elijah Newren committed Jul 5, 2022 at 01:33 UTC 751e16542472c7040565f97c2149c2d501ed0b81

2 files changed +9 -3

merge-ort.c

+7 -1

@@ -2292,10 +2292,16 @@ static char *check_for_directory_rename(struct merge_options *opt,

2292 struct strmap_entry *rename_info;

2293 struct strmap_entry *otherinfo;

2294 const char *new_dir;

2295 + int other_side = 3 - side_index;

2296

2296 - /* Cases where we don't have a directory rename for this path */

2297 + /*

2298 + * Cases where we don't have or don't want a directory rename for

2299 + * this path.

2300 + */

2301 if (strmap_empty(dir_renames))

2302 return NULL;

2303 + if (strmap_get(&collisions[other_side], path))

2304 + return NULL;

2305 rename_info = check_dir_renamed(path, dir_renames);

2306 if (!rename_info)

2307 return NULL;

t/t6423-merge-rename-directories.sh

+2 -2

@@ -5250,7 +5250,7 @@ test_setup_12l () {

5250 )

5251 }

5252

5253 -test_expect_merge_algorithm failure failure '12l (B into A): Rename into each other + add/add conflict' '

5253 +test_expect_merge_algorithm failure success '12l (B into A): Rename into each other + add/add conflict' '

5254 test_setup_12l BintoA &&

5255 (

5256 cd 12l_BintoA &&

@@ -5277,7 +5277,7 @@ test_expect_merge_algorithm failure failure '12l (B into A): Rename into each ot

5277 )

5278 '

5279

5280 -test_expect_merge_algorithm failure failure '12l (A into B): Rename into each other + add/add conflict' '

5280 +test_expect_merge_algorithm failure success '12l (A into B): Rename into each other + add/add conflict' '

5281 test_setup_12l AintoB &&

5282 (

5283 cd 12l_AintoB &&