tests: add a testcase for "git submodule sync"

[git.git] / diffcore-break.c

diff --git a/diffcore-break.c b/diffcore-break.c
index 0fc2b860bef30ee5a37b90df835e66f0dc74ab70..31cdcfe8bcdae7df65b0387071846299a14bb7be 100644 (file)
--- a/diffcore-break.c
+++ b/diffcore-break.c
@@ -45,60 +45,72 @@ static int should_break(struct diff_filespec *src,
         * The value we return is 1 if we want the pair to be broken,
         * or 0 if we do not.
         */
-       unsigned long delta_size, base_size, src_copied, literal_added;
-       int to_break = 0;
+       unsigned long delta_size, base_size, max_size;
+       unsigned long src_copied, literal_added, src_removed;
 
        *merge_score_p = 0; /* assume no deletion --- "do not break"
                             * is the default.
                             */
 
-       if (!S_ISREG(src->mode) || !S_ISREG(dst->mode))
-               return 0; /* leave symlink rename alone */
+       if (S_ISREG(src->mode) != S_ISREG(dst->mode)) {
+               *merge_score_p = (int)MAX_SCORE;
+               return 1; /* even their types are different */
+       }
 
        if (src->sha1_valid && dst->sha1_valid &&
-           !memcmp(src->sha1, dst->sha1, 20))
+           !hashcmp(src->sha1, dst->sha1))
                return 0; /* they are the same */
 
        if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
                return 0; /* error but caught downstream */
 
        base_size = ((src->size < dst->size) ? src->size : dst->size);
-       if (base_size < MINIMUM_BREAK_SIZE)
+       max_size = ((src->size > dst->size) ? src->size : dst->size);
+       if (max_size < MINIMUM_BREAK_SIZE)
                return 0; /* we do not break too small filepair */
 
-       if (diffcore_count_changes(src->data, src->size,
-                                  dst->data, dst->size,
+       if (diffcore_count_changes(src, dst,
+                                  NULL, NULL,
                                   0,
                                   &src_copied, &literal_added))
                return 0;
 
+       /* sanity */
+       if (src->size < src_copied)
+               src_copied = src->size;
+       if (dst->size < literal_added + src_copied) {
+               if (src_copied < dst->size)
+                       literal_added = dst->size - src_copied;
+               else
+                       literal_added = 0;
+       }
+       src_removed = src->size - src_copied;
+
        /* Compute merge-score, which is "how much is removed
         * from the source material".  The clean-up stage will
         * merge the surviving pair together if the score is
         * less than the minimum, after rename/copy runs.
         */
-       if (src->size <= src_copied)
-               ; /* all copied, nothing removed */
-       else {
-               delta_size = src->size - src_copied;
-               *merge_score_p = delta_size * MAX_SCORE / src->size;
-       }
-       
+       *merge_score_p = (int)(src_removed * MAX_SCORE / src->size);
+       if (*merge_score_p > break_score)
+               return 1;
+
        /* Extent of damage, which counts both inserts and
         * deletes.
         */
-       if (src->size + literal_added <= src_copied)
-               delta_size = 0; /* avoid wrapping around */
-       else
-               delta_size = (src->size - src_copied) + literal_added;
-       
-       /* We break if the edit exceeds the minimum.
-        * i.e. (break_score / MAX_SCORE < delta_size / base_size)
+       delta_size = src_removed + literal_added;
+       if (delta_size * MAX_SCORE / max_size < break_score)
+               return 0;
+
+       /* If you removed a lot without adding new material, that is
+        * not really a rewrite.
         */
-       if (break_score * base_size < delta_size * MAX_SCORE)
-               to_break = 1;
+       if ((src->size * break_score < src_removed * MAX_SCORE) &&
+           (literal_added * 20 < src_removed) &&
+           (literal_added * 20 < src_copied))
+               return 0;
 
-       return to_break;
+       return 1;
 }
 
 void diffcore_break(int break_score)
@@ -158,11 +170,13 @@ void diffcore_break(int break_score)
                struct diff_filepair *p = q->queue[i];
                int score;
 
-               /* We deal only with in-place edit of non directory.
+               /*
+                * We deal only with in-place edit of blobs.
                 * We do not break anything else.
                 */
                if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two) &&
-                   !S_ISDIR(p->one->mode) && !S_ISDIR(p->two->mode) &&
+                   object_type(p->one->mode) == OBJ_BLOB &&
+                   object_type(p->two->mode) == OBJ_BLOB &&
                    !strcmp(p->one->path, p->two->path)) {
                        if (should_break(p->one, p->two,
                                         break_score, &score)) {