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,
 static void remove_tempfile_on_signal(int signo)
 {
        remove_tempfile();
+       signal(SIGINT, SIG_DFL);
+       raise(signo);
 }
 
 /* An external diff command takes:
 
        if (memcmp(one->sha1, two->sha1, 20)) {
                char one_sha1[41];
-               int abbrev = o->full_index ? 40 : DIFF_DEFAULT_INDEX_ABBREV;
+               int abbrev = o->full_index ? 40 : DEFAULT_ABBREV;
                memcpy(one_sha1, sha1_to_hex(one->sha1), 41);
 
                len += snprintf(msg + len, sizeof(msg) - len,
                         * so it is safe for us to do this here.  Also
                         * it does not smudge active_cache or active_nr
                         * when it fails, so we do not have to worry about
-                        * cleaning it up oufselves either.
+                        * cleaning it up ourselves either.
                         */
                        read_cache();
        }
        else if (!strcmp(arg, "--find-copies-harder"))
                options->find_copies_harder = 1;
        else if (!strcmp(arg, "--abbrev"))
-               options->abbrev = DIFF_DEFAULT_ABBREV;
-       else if (!strncmp(arg, "--abbrev=", 9))
+               options->abbrev = DEFAULT_ABBREV;
+       else if (!strncmp(arg, "--abbrev=", 9)) {
                options->abbrev = strtoul(arg + 9, NULL, 10);
+               if (options->abbrev < MINIMUM_ABBREV)
+                       options->abbrev = MINIMUM_ABBREV;
+               else if (40 < options->abbrev)
+                       options->abbrev = 40;
+       }
        else
                return 0;
        return 1;
 }
 
 /* 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)
 {
                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];