Merge branch 'jh/diff-index-line-abbrev'

* jh/diff-index-line-abbrev:
diff.c: Ensure "index $from..$to" line contains unambiguous SHA1s

Conflicts:
diff.c

diff --combined diff.c
index c82b605a942b8611c3eaf0e41a173185fdb40779,1aefa663752965169c8cc5e0e40147c956bc4917..b53b6ec8e2ced8c94c0353dddf07ca5c1dd79978
--- 1/diff.c
--- 2/diff.c
+++ b/diff.c
@@@ -30,7 -30,6 +30,7 @@@ static const char *diff_word_regex_cfg
  static const char *external_diff_cmd_cfg;
  int diff_auto_refresh_index = 1;
  static int diff_mnemonic_prefix;
 +static int diff_no_prefix;
  
  static char diff_colors[][COLOR_MAXLEN] = {
        GIT_COLOR_RESET,
@@@ -102,10 -101,6 +102,10 @@@ int git_diff_ui_config(const char *var
                diff_mnemonic_prefix = git_config_bool(var, value);
                return 0;
        }
 +      if (!strcmp(var, "diff.noprefix")) {
 +              diff_no_prefix = git_config_bool(var, value);
 +              return 0;
 +      }
        if (!strcmp(var, "diff.external"))
                return git_config_string(&external_diff_cmd_cfg, var, value);
        if (!strcmp(var, "diff.wordregex"))
@@@ -759,7 -754,7 +759,7 @@@ static void diff_words_show(struct diff
        memset(&xecfg, 0, sizeof(xecfg));
        diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
        diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
 -      xpp.flags = XDF_NEED_MINIMAL;
 +      xpp.flags = 0;
        /* as only the hunk header will be parsed, we need a 0-context */
        xecfg.ctxlen = 0;
        xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
@@@ -1711,21 -1706,21 +1711,21 @@@ static void builtin_diff(const char *na
        if (lbl[0][0] == '/') {
                /* /dev/null */
                strbuf_addf(&header, "%snew file mode %06o%s\n", set, two->mode, reset);
 -              if (xfrm_msg && xfrm_msg[0])
 -                      strbuf_addf(&header, "%s%s%s\n", set, xfrm_msg, reset);
 +              if (xfrm_msg)
 +                      strbuf_addstr(&header, xfrm_msg);
        }
        else if (lbl[1][0] == '/') {
                strbuf_addf(&header, "%sdeleted file mode %06o%s\n", set, one->mode, reset);
 -              if (xfrm_msg && xfrm_msg[0])
 -                      strbuf_addf(&header, "%s%s%s\n", set, xfrm_msg, reset);
 +              if (xfrm_msg)
 +                      strbuf_addstr(&header, xfrm_msg);
        }
        else {
                if (one->mode != two->mode) {
                        strbuf_addf(&header, "%sold mode %06o%s\n", set, one->mode, reset);
                        strbuf_addf(&header, "%snew mode %06o%s\n", set, two->mode, reset);
                }
 -              if (xfrm_msg && xfrm_msg[0])
 -                      strbuf_addf(&header, "%s%s%s\n", set, xfrm_msg, reset);
 +              if (xfrm_msg)
 +                      strbuf_addstr(&header, xfrm_msg);
  
                /*
                 * we do not run diff between different kind
@@@ -1794,7 -1789,7 +1794,7 @@@
                        check_blank_at_eof(&mf1, &mf2, &ecbdata);
                ecbdata.file = o->file;
                ecbdata.header = header.len ? &header : NULL;
 -              xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
 +              xpp.flags = o->xdl_opts;
                xecfg.ctxlen = o->context;
                xecfg.interhunkctxlen = o->interhunkcontext;
                xecfg.flags = XDL_EMIT_FUNCNAMES;
@@@ -1899,7 -1894,7 +1899,7 @@@ static void builtin_diffstat(const cha
  
                memset(&xpp, 0, sizeof(xpp));
                memset(&xecfg, 0, sizeof(xecfg));
 -              xpp.flags = XDF_NEED_MINIMAL | o->xdl_opts;
 +              xpp.flags = o->xdl_opts;
                xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
                              &xpp, &xecfg);
        }
@@@ -1947,7 -1942,7 +1947,7 @@@ static void builtin_checkdiff(const cha
                memset(&xpp, 0, sizeof(xpp));
                memset(&xecfg, 0, sizeof(xecfg));
                xecfg.ctxlen = 1; /* at least one context line */
 -              xpp.flags = XDF_NEED_MINIMAL;
 +              xpp.flags = 0;
                xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
                              &xpp, &xecfg);
  
@@@ -2384,36 -2379,30 +2384,36 @@@ static void fill_metainfo(struct strbu
                          struct diff_filespec *one,
                          struct diff_filespec *two,
                          struct diff_options *o,
 -                        struct diff_filepair *p)
 +                        struct diff_filepair *p,
 +                        int use_color)
  {
 +      const char *set = diff_get_color(use_color, DIFF_METAINFO);
 +      const char *reset = diff_get_color(use_color, DIFF_RESET);
 +
        strbuf_init(msg, PATH_MAX * 2 + 300);
        switch (p->status) {
        case DIFF_STATUS_COPIED:
 -              strbuf_addf(msg, "similarity index %d%%", similarity_index(p));
 -              strbuf_addstr(msg, "\ncopy from ");
 +              strbuf_addf(msg, "%ssimilarity index %d%%",
 +                          set, similarity_index(p));
 +              strbuf_addf(msg, "%s\n%scopy from ", reset, set);
                quote_c_style(name, msg, NULL, 0);
 -              strbuf_addstr(msg, "\ncopy to ");
 +              strbuf_addf(msg, "%s\n%scopy to ", reset, set);
                quote_c_style(other, msg, NULL, 0);
 -              strbuf_addch(msg, '\n');
 +              strbuf_addf(msg, "%s\n", reset);
                break;
        case DIFF_STATUS_RENAMED:
 -              strbuf_addf(msg, "similarity index %d%%", similarity_index(p));
 -              strbuf_addstr(msg, "\nrename from ");
 +              strbuf_addf(msg, "%ssimilarity index %d%%",
 +                          set, similarity_index(p));
 +              strbuf_addf(msg, "%s\n%srename from ", reset, set);
                quote_c_style(name, msg, NULL, 0);
 -              strbuf_addstr(msg, "\nrename to ");
 +              strbuf_addf(msg, "%s\n%srename to ", reset, set);
                quote_c_style(other, msg, NULL, 0);
 -              strbuf_addch(msg, '\n');
 +              strbuf_addf(msg, "%s\n", reset);
                break;
        case DIFF_STATUS_MODIFIED:
                if (p->score) {
 -                      strbuf_addf(msg, "dissimilarity index %d%%\n",
 -                                  similarity_index(p));
 +                      strbuf_addf(msg, "%sdissimilarity index %d%%%s\n",
 +                                  set, similarity_index(p), reset);
                        break;
                }
                /* fallthru */
@@@ -2430,13 -2419,15 +2430,13 @@@
                            (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
                                abbrev = 40;
                }
-               strbuf_addf(msg, "%sindex %.*s..%.*s", set,
-                           abbrev, sha1_to_hex(one->sha1),
-                           abbrev, sha1_to_hex(two->sha1));
 -              strbuf_addf(msg, "index %s..",
++              strbuf_addf(msg, "%sindex %s..", set,
+                           find_unique_abbrev(one->sha1, abbrev));
+               strbuf_addstr(msg, find_unique_abbrev(two->sha1, abbrev));
                if (one->mode == two->mode)
                        strbuf_addf(msg, " %06o", one->mode);
 -              strbuf_addch(msg, '\n');
 +              strbuf_addf(msg, "%s\n", reset);
        }
 -      if (msg->len)
 -              strbuf_setlen(msg, msg->len - 1);
  }
  
  static void run_diff_cmd(const char *pgm,
@@@ -2452,6 -2443,11 +2452,6 @@@
        const char *xfrm_msg = NULL;
        int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
  
 -      if (msg) {
 -              fill_metainfo(msg, name, other, one, two, o, p);
 -              xfrm_msg = msg->len ? msg->buf : NULL;
 -      }
 -
        if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
                pgm = NULL;
        else {
@@@ -2460,16 -2456,6 +2460,16 @@@
                        pgm = drv->external;
        }
  
 +      if (msg) {
 +              /*
 +               * don't use colors when the header is intended for an
 +               * external diff driver
 +               */
 +              fill_metainfo(msg, name, other, one, two, o, p,
 +                            DIFF_OPT_TST(o, COLOR_DIFF) && !pgm);
 +              xfrm_msg = msg->len ? msg->buf : NULL;
 +      }
 +
        if (pgm) {
                run_external_diff(pgm, name, other, one, two, xfrm_msg,
                                  complete_rewrite);
@@@ -2630,9 -2616,7 +2630,9 @@@ void diff_setup(struct diff_options *op
                DIFF_OPT_SET(options, COLOR_DIFF);
        options->detect_rename = diff_detect_rename_default;
  
 -      if (!diff_mnemonic_prefix) {
 +      if (diff_no_prefix) {
 +              options->a_prefix = options->b_prefix = "";
 +      } else if (!diff_mnemonic_prefix) {
                options->a_prefix = "a/";
                options->b_prefix = "b/";
        }
@@@ -3537,7 -3521,7 +3537,7 @@@ static int diff_get_patch_id(struct dif
                                        len2, p->two->path);
                git_SHA1_Update(&ctx, buffer, len1);
  
 -              xpp.flags = XDF_NEED_MINIMAL;
 +              xpp.flags = 0;
                xecfg.ctxlen = 3;
                xecfg.flags = XDL_EMIT_FUNCNAMES;
                xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,