Fix off-by-one error in git-merge

diff --git a/diffcore-rename.c b/diffcore-rename.c
index 8fb45f0b8706baa6a1190b21d723d0b0d81203c5..dbc85221320ed06e332fab25325020da241bde78 100644 (file)
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -55,12 +55,12 @@ static struct diff_rename_dst *locate_rename_dst(struct diff_filespec *two,
 /* Table of rename/copy src files */
 static struct diff_rename_src {
        struct diff_filespec *one;
-       unsigned src_stays : 1;
+       unsigned src_path_left : 1;
 } *rename_src;
 static int rename_src_nr, rename_src_alloc;
 
 static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
-                                                  int src_stays)
+                                                  int src_path_left)
 {
        int first, last;
 
@@ -90,7 +90,7 @@ static struct diff_rename_src *register_rename_src(struct diff_filespec *one,
                memmove(rename_src + first + 1, rename_src + first,
                        (rename_src_nr - first - 1) * sizeof(*rename_src));
        rename_src[first].one = one;
-       rename_src[first].src_stays = src_stays;
+       rename_src[first].src_path_left = src_path_left;
        return &(rename_src[first]);
 }
 
@@ -136,6 +136,7 @@ static int estimate_similarity(struct diff_filespec *src,
         */
        void *delta;
        unsigned long delta_size, base_size, src_copied, literal_added;
+       unsigned long delta_limit;
        int score;
 
        /* We deal only with regular files.  Symlink renames are handled
@@ -163,9 +164,13 @@ static int estimate_similarity(struct diff_filespec *src,
        if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
                return 0; /* error but caught downstream */
 
+       delta_limit = base_size * (MAX_SCORE-minimum_score) / MAX_SCORE;
        delta = diff_delta(src->data, src->size,
                           dst->data, dst->size,
-                          &delta_size);
+                          &delta_size, delta_limit);
+       if (!delta)
+               /* If delta_limit is exceeded, we have too much differences */
+               return 0;
 
        /* A delta that has a lot of literal additions would have
         * big delta_size no matter what else it does.
@@ -215,7 +220,7 @@ static void record_rename_pair(struct diff_queue_struct *renq,
 
        dp = diff_queue(renq, one, two);
        dp->score = score;
-       dp->source_stays = rename_src[src_index].src_stays;
+       dp->source_stays = rename_src[src_index].src_path_left;
        rename_dst[dst_index].pair = dp;
 }
 
@@ -229,6 +234,21 @@ static int score_compare(const void *a_, const void *b_)
        return b->score - a->score;
 }
 
+static int compute_stays(struct diff_queue_struct *q,
+                        struct diff_filespec *one)
+{
+       int i;
+       for (i = 0; i < q->nr; i++) {
+               struct diff_filepair *p = q->queue[i];
+               if (strcmp(one->path, p->two->path))
+                       continue;
+               if (DIFF_PAIR_RENAME(p)) {
+                       return 0; /* something else is renamed into this */
+               }
+       }
+       return 1;
+}
+
 void diffcore_rename(int detect_rename, int minimum_score)
 {
        struct diff_queue_struct *q = &diff_queued_diff;
@@ -401,6 +421,23 @@ void diffcore_rename(int detect_rename, int minimum_score)
        *q = outq;
        diff_debug_queue("done collapsing", q);
 
+       /* We need to see which rename source really stays here;
+        * earlier we only checked if the path is left in the result,
+        * but even if a path remains in the result, if that is coming
+        * from copying something else on top of it, then the original
+        * source is lost and does not stay.
+        */
+       for (i = 0; i < q->nr; i++) {
+               struct diff_filepair *p = q->queue[i];
+               if (DIFF_PAIR_RENAME(p) && p->source_stays) {
+                       /* If one appears as the target of a rename-copy,
+                        * then mark p->source_stays = 0; otherwise
+                        * leave it as is.
+                        */
+                       p->source_stays = compute_stays(q, p->one);
+               }
+       }
+
        free(rename_dst);
        rename_dst = NULL;
        rename_dst_nr = rename_dst_alloc = 0;