Merge branch 'lt/diff-tree'

* lt/diff-tree:
  combine-diff: Record diff status a bit more faithfully
  find_unique_abbrev() simplification.

diff --combined diff.c
index c72064e,890bdaa..804c08c
--- 1/diff.c
--- 2/diff.c
+++ b/diff.c
@@@ -311,7 -311,7 +311,7 @@@ static int work_tree_matches(const cha
        ce = active_cache[pos];
        if ((lstat(name, &st) < 0) ||
            !S_ISREG(st.st_mode) || /* careful! */
 -          ce_match_stat(ce, &st) ||
 +          ce_match_stat(ce, &st, 0) ||
            memcmp(sha1, ce->sha1, 20))
                return 0;
        /* we return 1 only when we can stat, it is a regular file,
@@@ -963,7 -963,7 +963,7 @@@ void diff_free_filepair(struct diff_fil
  }
  
  /* This is different from find_unique_abbrev() in that
-  * it needs to deal with 0{40} SHA1.
+  * it stuffs the result with dots for alignment.
   */
  const char *diff_unique_abbrev(const unsigned char *sha1, int len)
  {
@@@ -973,16 -973,8 +973,8 @@@
                return sha1_to_hex(sha1);
  
        abbrev = find_unique_abbrev(sha1, len);
-       if (!abbrev) {
-               if (!memcmp(sha1, null_sha1, 20)) {
-                       char *buf = sha1_to_hex(null_sha1);
-                       if (len < 37)
-                               strcpy(buf + len, "...");
-                       return buf;
-               }
-               else 
-                       return sha1_to_hex(sha1);
-       }
+       if (!abbrev)
+               return sha1_to_hex(sha1);
        abblen = strlen(abbrev);
        if (abblen < 37) {
                static char hex[41];