[PATCH] git-apply: Don't barf when --stat'ing a diff with no line changes.
[gitweb.git] / diffcore-rename.c
index 6389dedbf9c45a7c9fd976b749175557c401cbcd..8fb45f0b8706baa6a1190b21d723d0b0d81203c5 100644 (file)
@@ -99,8 +99,11 @@ static int is_exact_match(struct diff_filespec *src, struct diff_filespec *dst)
        if (src->sha1_valid && dst->sha1_valid &&
            !memcmp(src->sha1, dst->sha1, 20))
                return 1;
-       if (diff_populate_filespec(src) || diff_populate_filespec(dst))
-               /* this is an error but will be caught downstream */
+       if (diff_populate_filespec(src, 1) || diff_populate_filespec(dst, 1))
+               return 0;
+       if (src->size != dst->size)
+               return 0;
+       if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
                return 0;
        if (src->size == dst->size &&
            !memcmp(src->data, dst->data, src->size))
@@ -125,12 +128,14 @@ static int estimate_similarity(struct diff_filespec *src,
         * dst, and then some edit has been applied to dst.
         *
         * Compare them and return how similar they are, representing
-        * the score as an integer between 0 and 10000, except
-        * where they match exactly it is considered better than anything
-        * else.
+        * the score as an integer between 0 and MAX_SCORE.
+        *
+        * When there is an exact match, it is considered a better
+        * match than anything else; the destination does not even
+        * call into this function in that case.
         */
        void *delta;
-       unsigned long delta_size, base_size;
+       unsigned long delta_size, base_size, src_copied, literal_added;
        int score;
 
        /* We deal only with regular files.  Symlink renames are handled
@@ -147,6 +152,7 @@ static int estimate_similarity(struct diff_filespec *src,
        /* We would not consider edits that change the file size so
         * drastically.  delta_size must be smaller than
         * (MAX_SCORE-minimum_score)/MAX_SCORE * min(src->size, dst->size).
+        *
         * Note that base_size == 0 case is handled here already
         * and the final score computation below would not have a
         * divide-by-zero issue.
@@ -154,6 +160,9 @@ static int estimate_similarity(struct diff_filespec *src,
        if (base_size * (MAX_SCORE-minimum_score) < delta_size * MAX_SCORE)
                return 0;
 
+       if (diff_populate_filespec(src, 0) || diff_populate_filespec(dst, 0))
+               return 0; /* error but caught downstream */
+
        delta = diff_delta(src->data, src->size,
                           dst->data, dst->size,
                           &delta_size);
@@ -165,10 +174,17 @@ static int estimate_similarity(struct diff_filespec *src,
                return 0;
 
        /* Estimate the edit size by interpreting delta. */
-       delta_size = count_delta(delta, delta_size);
-       free(delta);
-       if (delta_size == UINT_MAX)
+       if (count_delta(delta, delta_size, &src_copied, &literal_added)) {
+               free(delta);
                return 0;
+       }
+       free(delta);
+
+       /* Extent of damage */
+       if (src->size + literal_added < src_copied)
+               delta_size = 0;
+       else
+               delta_size = (src->size - src_copied) + literal_added;
 
        /*
         * Now we will give some score to it.  100% edit gets 0 points
@@ -198,7 +214,7 @@ static void record_rename_pair(struct diff_queue_struct *renq,
        fill_filespec(two, dst->sha1, dst->mode);
 
        dp = diff_queue(renq, one, two);
-       dp->score = score ? : 1; /* make sure it is at least 1 */
+       dp->score = score;
        dp->source_stays = rename_src[src_index].src_stays;
        rename_dst[dst_index].pair = dp;
 }
@@ -213,24 +229,6 @@ static int score_compare(const void *a_, const void *b_)
        return b->score - a->score;
 }
 
-int diff_scoreopt_parse(const char *opt)
-{
-       int diglen, num, scale, i;
-       if (opt[0] != '-' || (opt[1] != 'M' && opt[1] != 'C'))
-               return -1; /* that is not a -M nor -C option */
-       diglen = strspn(opt+2, "0123456789");
-       if (diglen == 0 || strlen(opt+2) != diglen)
-               return 0; /* use default */
-       sscanf(opt+2, "%d", &num);
-       for (i = 0, scale = 1; i < diglen; i++)
-               scale *= 10;
-
-       /* user says num divided by scale and we say internally that
-        * is MAX_SCORE * num / scale.
-        */
-       return MAX_SCORE * num / scale;
-}
-
 void diffcore_rename(int detect_rename, int minimum_score)
 {
        struct diff_queue_struct *q = &diff_queued_diff;
@@ -240,7 +238,7 @@ void diffcore_rename(int detect_rename, int minimum_score)
        int num_create, num_src, dst_cnt;
 
        if (!minimum_score)
-               minimum_score = DEFAULT_MINIMUM_SCORE;
+               minimum_score = DEFAULT_RENAME_SCORE;
        renq.queue = NULL;
        renq.nr = renq.alloc = 0;
 
@@ -251,8 +249,14 @@ void diffcore_rename(int detect_rename, int minimum_score)
                                continue; /* unmerged */
                        else
                                locate_rename_dst(p->two, 1);
-               else if (!DIFF_FILE_VALID(p->two))
-                       register_rename_src(p->one, 0);
+               else if (!DIFF_FILE_VALID(p->two)) {
+                       /* If the source is a broken "delete", and
+                        * they did not really want to get broken,
+                        * that means the source actually stays.
+                        */
+                       int stays = (p->broken_pair && !p->score);
+                       register_rename_src(p->one, stays);
+               }
                else if (detect_rename == DIFF_DETECT_COPY)
                        register_rename_src(p->one, 1);
        }
@@ -319,26 +323,67 @@ void diffcore_rename(int detect_rename, int minimum_score)
        outq.nr = outq.alloc = 0;
        for (i = 0; i < q->nr; i++) {
                struct diff_filepair *p = q->queue[i];
-               struct diff_rename_dst *dst = locate_rename_dst(p->two, 0);
                struct diff_filepair *pair_to_free = NULL;
 
-               if (dst) {
-                       /* creation */
-                       if (dst->pair) {
-                               /* renq has rename/copy to produce
-                                * this file already, so we do not
-                                * emit the creation record in the
-                                * output.
-                                */
+               if (!DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
+                       /*
+                        * Creation
+                        *
+                        * We would output this create record if it has
+                        * not been turned into a rename/copy already.
+                        */
+                       struct diff_rename_dst *dst =
+                               locate_rename_dst(p->two, 0);
+                       if (dst && dst->pair) {
                                diff_q(&outq, dst->pair);
                                pair_to_free = p;
                        }
                        else
-                               /* no matching rename/copy source, so record
-                                * this as a creation.
+                               /* no matching rename/copy source, so
+                                * record this as a creation.
                                 */
                                diff_q(&outq, p);
                }
+               else if (DIFF_FILE_VALID(p->one) && !DIFF_FILE_VALID(p->two)) {
+                       /*
+                        * Deletion
+                        *
+                        * We would output this delete record if:
+                        *
+                        * (1) this is a broken delete and the counterpart
+                        *     broken create remains in the output; or
+                        * (2) this is not a broken delete, and renq does
+                        *     not have a rename/copy to move p->one->path
+                        *     out.
+                        *
+                        * Otherwise, the counterpart broken create
+                        * has been turned into a rename-edit; or
+                        * delete did not have a matching create to
+                        * begin with.
+                        */
+                       if (DIFF_PAIR_BROKEN(p)) {
+                               /* broken delete */
+                               struct diff_rename_dst *dst =
+                                       locate_rename_dst(p->one, 0);
+                               if (dst && dst->pair)
+                                       /* counterpart is now rename/copy */
+                                       pair_to_free = p;
+                       }
+                       else {
+                               for (j = 0; j < renq.nr; j++)
+                                       if (!strcmp(renq.queue[j]->one->path,
+                                                   p->one->path))
+                                               break;
+                               if (j < renq.nr)
+                                       /* this path remains */
+                                       pair_to_free = p;
+                       }
+
+                       if (pair_to_free)
+                               ;
+                       else
+                               diff_q(&outq, p);
+               }
                else if (!diff_unmodified_pair(p))
                        /* all the usual ones need to be kept */
                        diff_q(&outq, p);