Merge branch 'jk/diff-CBM'

* jk/diff-CBM:
diff: report bogus input to -C/-M/-B

diff --combined diff.c
index db5e84443bfe915b5e44ec2fc573ebdb95dd20c1,84876431bc64c72a3e632d40eb8a13d270fc9a56..6991ed4e17343a3104d3fd518b5d85d0913e9259
--- 1/diff.c
--- 2/diff.c
+++ b/diff.c
@@@ -1771,14 -1771,8 +1771,14 @@@ static void emit_binary_diff(FILE *file
  
  static void diff_filespec_load_driver(struct diff_filespec *one)
  {
 -      if (!one->driver)
 +      /* Use already-loaded driver */
 +      if (one->driver)
 +              return;
 +
 +      if (S_ISREG(one->mode))
                one->driver = userdiff_find_by_path(one->path);
 +
 +      /* Fallback to default settings */
        if (!one->driver)
                one->driver = userdiff_find_by_name("default");
  }
@@@ -1826,7 -1820,8 +1826,7 @@@ struct userdiff_driver *get_textconv(st
  {
        if (!DIFF_FILE_VALID(one))
                return NULL;
 -      if (!S_ISREG(one->mode))
 -              return NULL;
 +
        diff_filespec_load_driver(one);
        if (!one->driver->textconv)
                return NULL;
@@@ -2158,7 -2153,7 +2158,7 @@@ static void builtin_checkdiff(const cha
  
                        ecbdata.ws_rule = data.ws_rule;
                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
 -                      blank_at_eof = ecbdata.blank_at_eof_in_preimage;
 +                      blank_at_eof = ecbdata.blank_at_eof_in_postimage;
  
                        if (blank_at_eof) {
                                static char *err;
@@@ -2391,14 -2386,10 +2391,14 @@@ int diff_populate_filespec(struct diff_
        }
        else {
                enum object_type type;
 -              if (size_only)
 +              if (size_only) {
                        type = sha1_object_info(s->sha1, &s->size);
 -              else {
 +                      if (type < 0)
 +                              die("unable to read %s", sha1_to_hex(s->sha1));
 +              } else {
                        s->data = read_sha1_file(s->sha1, &type, &s->size);
 +                      if (!s->data)
 +                              die("unable to read %s", sha1_to_hex(s->sha1));
                        s->should_free = 1;
                }
        }
@@@ -3149,23 -3140,20 +3149,23 @@@ int diff_opt_parse(struct diff_options 
                return stat_opt(options, av);
  
        /* renames options */
 -      else if (!prefixcmp(arg, "-B")) {
 +      else if (!prefixcmp(arg, "-B") || !prefixcmp(arg, "--break-rewrites=") ||
 +               !strcmp(arg, "--break-rewrites")) {
                if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
-                       return -1;
+                       return error("invalid argument to -B: %s", arg+2);
        }
 -      else if (!prefixcmp(arg, "-M")) {
 +      else if (!prefixcmp(arg, "-M") || !prefixcmp(arg, "--detect-renames=") ||
 +               !strcmp(arg, "--detect-renames")) {
                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
-                       return -1;
+                       return error("invalid argument to -M: %s", arg+2);
                options->detect_rename = DIFF_DETECT_RENAME;
        }
 -      else if (!prefixcmp(arg, "-C")) {
 +      else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--detect-copies=") ||
 +               !strcmp(arg, "--detect-copies")) {
                if (options->detect_rename == DIFF_DETECT_COPY)
                        DIFF_OPT_SET(options, FIND_COPIES_HARDER);
                if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
-                       return -1;
+                       return error("invalid argument to -C: %s", arg+2);
                options->detect_rename = DIFF_DETECT_COPY;
        }
        else if (!strcmp(arg, "--no-renames"))
@@@ -3335,7 -3323,7 +3335,7 @@@
        return 1;
  }
  
 -static int parse_num(const char **cp_p)
 +int parse_rename_score(const char **cp_p)
  {
        unsigned long num, scale;
        int ch, dot;
@@@ -3378,26 -3366,10 +3378,26 @@@ static int diff_scoreopt_parse(const ch
        if (*opt++ != '-')
                return -1;
        cmd = *opt++;
 +      if (cmd == '-') {
 +              /* convert the long-form arguments into short-form versions */
 +              if (!prefixcmp(opt, "break-rewrites")) {
 +                      opt += strlen("break-rewrites");
 +                      if (*opt == 0 || *opt++ == '=')
 +                              cmd = 'B';
 +              } else if (!prefixcmp(opt, "detect-copies")) {
 +                      opt += strlen("detect-copies");
 +                      if (*opt == 0 || *opt++ == '=')
 +                              cmd = 'C';
 +              } else if (!prefixcmp(opt, "detect-renames")) {
 +                      opt += strlen("detect-renames");
 +                      if (*opt == 0 || *opt++ == '=')
 +                              cmd = 'M';
 +              }
 +      }
        if (cmd != 'M' && cmd != 'C' && cmd != 'B')
                return -1; /* that is not a -M, -C nor -B option */
  
 -      opt1 = parse_num(&opt);
 +      opt1 = parse_rename_score(&opt);
        if (cmd != 'B')
                opt2 = 0;
        else {
@@@ -3407,7 -3379,7 +3407,7 @@@
                        return -1; /* we expect -B80/99 or -B80 */
                else {
                        opt++;
 -                      opt2 = parse_num(&opt);
 +                      opt2 = parse_rename_score(&opt);
                }
        }
        if (*opt != 0)
@@@ -3560,7 -3532,7 +3560,7 @@@ static void diff_flush_stat(struct diff
  
        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
 -              return; /* no tree diffs in patch format */
 +              return; /* no useful stat for tree diffs */
  
        run_diffstat(p, o, diffstat);
  }
@@@ -3573,7 -3545,7 +3573,7 @@@ static void diff_flush_checkdiff(struc
  
        if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
            (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
 -              return; /* no tree diffs in patch format */
 +              return; /* nothing to check in tree diffs */
  
        run_checkdiff(p, o);
  }
@@@ -3898,7 -3870,7 +3898,7 @@@ static int diff_get_patch_id(struct dif
  
                xpp.flags = 0;
                xecfg.ctxlen = 3;
 -              xecfg.flags = XDL_EMIT_FUNCNAMES;
 +              xecfg.flags = 0;
                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
                              &xpp, &xecfg);
        }