merge-recursive: Make dead code for rename/rename(2to1) conflicts undead

The code for rename_rename_2to1 conflicts (two files both being renamed to
the same filename) was dead since the rename/add path was always being
independently triggered for each of the renames instead.  Further,
reviving the dead code showed that it was inherently buggy and would
always segfault -- among a few other bugs.

Move the else-if branch for the rename/rename block before the rename/add
block to make sure it is checked first, and fix up the rename/rename(2to1)
code segments to make it handle most cases.  Work is still needed to
handle higher dimensional corner cases such as rename/rename/modify/modify
issues.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/merge-recursive.c b/merge-recursive.c
index 089cfe8..47b32f7 100644 (file)
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -996,17 +996,36 @@ static void conflict_rename_rename_2to1(struct merge_options *o,
                                        struct rename *ren2,
                                        const char *branch2)
 {
+       char *path = ren1->pair->two->path; /* same as ren2->pair->two->path */
        /* Two files were renamed to the same thing. */
-       char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
-       char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
-       output(o, 1, "Renaming %s to %s and %s to %s instead",
-              ren1->pair->one->path, new_path1,
-              ren2->pair->one->path, new_path2);
-       remove_file(o, 0, ren1->pair->two->path, 0);
-       update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
-       update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
-       free(new_path2);
-       free(new_path1);
+       if (o->call_depth) {
+               struct merge_file_info mfi;
+               struct diff_filespec one, a, b;
+
+               one.path = a.path = b.path = path;
+               hashcpy(one.sha1, null_sha1);
+               one.mode = 0;
+               hashcpy(a.sha1, ren1->pair->two->sha1);
+               a.mode = ren1->pair->two->mode;
+               hashcpy(b.sha1, ren2->pair->two->sha1);
+               b.mode = ren2->pair->two->mode;
+               mfi = merge_file(o, &one, &a, &b, branch1, branch2);
+               output(o, 1, "Adding merged %s", path);
+               update_file(o, 0, mfi.sha, mfi.mode, path);
+       } else {
+               char *new_path1 = unique_path(o, path, branch1);
+               char *new_path2 = unique_path(o, path, branch2);
+               output(o, 1, "Renaming %s to %s and %s to %s instead",
+                      ren1->pair->one->path, new_path1,
+                      ren2->pair->one->path, new_path2);
+               remove_file(o, 0, path, 0);
+               update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode,
+                           new_path1);
+               update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode,
+                           new_path2);
+               free(new_path2);
+               free(new_path1);
+       }
 }
 
 static int process_renames(struct merge_options *o,
@@ -1021,12 +1040,12 @@ static int process_renames(struct merge_options *o,
        for (i = 0; i < a_renames->nr; i++) {
                sre = a_renames->items[i].util;
                string_list_insert(&a_by_dst, sre->pair->two->path)->util
-                       = sre->dst_entry;
+                       = (void *)sre;
        }
        for (i = 0; i < b_renames->nr; i++) {
                sre = b_renames->items[i].util;
                string_list_insert(&b_by_dst, sre->pair->two->path)->util
-                       = sre->dst_entry;
+                       = (void *)sre;
        }
 
        for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
@@ -1138,6 +1157,23 @@ static int process_renames(struct merge_options *o,
                                        clean_merge = 0;
                                        conflict_rename_delete(o, ren1->pair, branch1, branch2);
                                }
+                       } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
+                               char *ren2_src, *ren2_dst;
+                               ren2 = item->util;
+                               ren2_src = ren2->pair->one->path;
+                               ren2_dst = ren2->pair->two->path;
+
+                               clean_merge = 0;
+                               ren2->processed = 1;
+                               remove_file(o, 1, ren2_src,
+                                           renamed_stage == 3 || would_lose_untracked(ren1_src));
+
+                               output(o, 1, "CONFLICT (rename/rename): "
+                                      "Rename %s->%s in %s. "
+                                      "Rename %s->%s in %s",
+                                      ren1_src, ren1_dst, branch1,
+                                      ren2_src, ren2_dst, branch2);
+                               conflict_rename_rename_2to1(o, ren1, branch1, ren2, branch2);
                        } else if ((dst_other.mode == ren1->pair->two->mode) &&
                                   sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
                                /* Added file on the other side
@@ -1178,16 +1214,6 @@ static int process_renames(struct merge_options *o,
                                        update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
                                        free(new_path);
                                }
-                       } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
-                               ren2 = item->util;
-                               clean_merge = 0;
-                               ren2->processed = 1;
-                               output(o, 1, "CONFLICT (rename/rename): "
-                                      "Rename %s->%s in %s. "
-                                      "Rename %s->%s in %s",
-                                      ren1_src, ren1_dst, branch1,
-                                      ren2->pair->one->path, ren2->pair->two->path, branch2);
-                               conflict_rename_rename_2to1(o, ren1, branch1, ren2, branch2);
                        } else
                                try_merge = 1;
 

diff --git a/t/t6036-recursive-corner-cases.sh b/t/t6036-recursive-corner-cases.sh
index 279f33c..b046e1b 100755 (executable)
--- a/t/t6036-recursive-corner-cases.sh
+++ b/t/t6036-recursive-corner-cases.sh
@@ -66,13 +66,13 @@ test_expect_success 'merge simple rename+criss-cross with no modifications' '
        test $(git rev-parse :2:three) = $(git rev-parse L2:three) &&
        test $(git rev-parse :3:three) = $(git rev-parse R2:three) &&
 
-       cp two merged &&
+       cp one merged &&
        >empty &&
        test_must_fail git merge-file \
-               -L "Temporary merge branch 2" \
-               -L "" \
                -L "Temporary merge branch 1" \
-               merged empty one &&
+               -L "" \
+               -L "Temporary merge branch 2" \
+               merged empty two &&
        test $(git rev-parse :1:three) = $(git hash-object merged)
 '
 
@@ -145,11 +145,12 @@ test_expect_success 'merge criss-cross + rename merges with basic modification'
        cp one merge-me &&
        >empty &&
        test_must_fail git merge-file \
-               -L "Temporary merge branch 2" \
-               -L "" \
                -L "Temporary merge branch 1" \
-               merged empty merge-me &&
-       test $(git rev-parse :1:three) = $(git hash-object merged)
+               -L "" \
+               -L "Temporary merge branch 2" \
+               merge-me empty merged &&
+
+       test $(git rev-parse :1:three) = $(git hash-object merge-me)
 '
 
 #