log-tree.c

   1 #include "cache.h"
   2 #include "diff.h"
   3 #include "commit.h"
   4 #include "tag.h"
   5 #include "graph.h"
   6 #include "log-tree.h"
   7 #include "reflog-walk.h"
   8 #include "refs.h"
   9 #include "string-list.h"
  10 #include "color.h"
  11
  12 struct decoration name_decoration = { "object names" };
  13
  14 enum decoration_type {
  15         DECORATION_NONE = 0,
  16         DECORATION_REF_LOCAL,
  17         DECORATION_REF_REMOTE,
  18         DECORATION_REF_TAG,
  19         DECORATION_REF_STASH,
  20         DECORATION_REF_HEAD,
  21         DECORATION_GRAFTED,
  22 };
  23
  24 static char decoration_colors[][COLOR_MAXLEN] = {
  25         GIT_COLOR_RESET,
  26         GIT_COLOR_BOLD_GREEN,   /* REF_LOCAL */
  27         GIT_COLOR_BOLD_RED,     /* REF_REMOTE */
  28         GIT_COLOR_BOLD_YELLOW,  /* REF_TAG */
  29         GIT_COLOR_BOLD_MAGENTA, /* REF_STASH */
  30         GIT_COLOR_BOLD_CYAN,    /* REF_HEAD */
  31         GIT_COLOR_BOLD_BLUE,    /* GRAFTED */
  32 };
  33
  34 static const char *decorate_get_color(int decorate_use_color, enum decoration_type ix)
  35 {
  36         if (decorate_use_color)
  37                 return decoration_colors[ix];
  38         return "";
  39 }
  40
  41 static int parse_decorate_color_slot(const char *slot)
  42 {
  43         /*
  44          * We're comparing with 'ignore-case' on
  45          * (because config.c sets them all tolower),
  46          * but let's match the letters in the literal
  47          * string values here with how they are
  48          * documented in Documentation/config.txt, for
  49          * consistency.
  50          *
  51          * We love being consistent, don't we?
  52          */
  53         if (!strcasecmp(slot, "branch"))
  54                 return DECORATION_REF_LOCAL;
  55         if (!strcasecmp(slot, "remoteBranch"))
  56                 return DECORATION_REF_REMOTE;
  57         if (!strcasecmp(slot, "tag"))
  58                 return DECORATION_REF_TAG;
  59         if (!strcasecmp(slot, "stash"))
  60                 return DECORATION_REF_STASH;
  61         if (!strcasecmp(slot, "HEAD"))
  62                 return DECORATION_REF_HEAD;
  63         return -1;
  64 }
  65
  66 int parse_decorate_color_config(const char *var, const int ofs, const char *value)
  67 {
  68         int slot = parse_decorate_color_slot(var + ofs);
  69         if (slot < 0)
  70                 return 0;
  71         if (!value)
  72                 return config_error_nonbool(var);
  73         color_parse(value, var, decoration_colors[slot]);
  74         return 0;
  75 }
  76
  77 /*
  78  * log-tree.c uses DIFF_OPT_TST for determining whether to use color
  79  * for showing the commit sha1, use the same check for --decorate
  80  */
  81 #define decorate_get_color_opt(o, ix) \
  82         decorate_get_color(DIFF_OPT_TST((o), COLOR_DIFF), ix)
  83
  84 static void add_name_decoration(enum decoration_type type, const char *name, struct object *obj)
  85 {
  86         int nlen = strlen(name);
  87         struct name_decoration *res = xmalloc(sizeof(struct name_decoration) + nlen);
  88         memcpy(res->name, name, nlen + 1);
  89         res->type = type;
  90         res->next = add_decoration(&name_decoration, obj, res);
  91 }
  92
  93 static int add_ref_decoration(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
  94 {
  95         struct object *obj = parse_object(sha1);
  96         enum decoration_type type = DECORATION_NONE;
  97         if (!obj)
  98                 return 0;
  99
 100         if (!prefixcmp(refname, "refs/heads/"))
 101                 type = DECORATION_REF_LOCAL;
 102         else if (!prefixcmp(refname, "refs/remotes/"))
 103                 type = DECORATION_REF_REMOTE;
 104         else if (!prefixcmp(refname, "refs/tags/"))
 105                 type = DECORATION_REF_TAG;
 106         else if (!prefixcmp(refname, "refs/stash"))
 107                 type = DECORATION_REF_STASH;
 108         else if (!prefixcmp(refname, "HEAD"))
 109                 type = DECORATION_REF_HEAD;
 110
 111         if (!cb_data || *(int *)cb_data == DECORATE_SHORT_REFS)
 112                 refname = prettify_refname(refname);
 113         add_name_decoration(type, refname, obj);
 114         while (obj->type == OBJ_TAG) {
 115                 obj = ((struct tag *)obj)->tagged;
 116                 if (!obj)
 117                         break;
 118                 add_name_decoration(DECORATION_REF_TAG, refname, obj);
 119         }
 120         return 0;
 121 }
 122
 123 static int add_graft_decoration(const struct commit_graft *graft, void *cb_data)
 124 {
 125         struct commit *commit = lookup_commit(graft->sha1);
 126         if (!commit)
 127                 return 0;
 128         add_name_decoration(DECORATION_GRAFTED, "grafted", &commit->object);
 129         return 0;
 130 }
 131
 132 void load_ref_decorations(int flags)
 133 {
 134         static int loaded;
 135         if (!loaded) {
 136                 loaded = 1;
 137                 for_each_ref(add_ref_decoration, &flags);
 138                 head_ref(add_ref_decoration, &flags);
 139                 for_each_commit_graft(add_graft_decoration, NULL);
 140         }
 141 }
 142
 143 static void show_parents(struct commit *commit, int abbrev)
 144 {
 145         struct commit_list *p;
 146         for (p = commit->parents; p ; p = p->next) {
 147                 struct commit *parent = p->item;
 148                 printf(" %s", find_unique_abbrev(parent->object.sha1, abbrev));
 149         }
 150 }
 151
 152 void show_decorations(struct rev_info *opt, struct commit *commit)
 153 {
 154         const char *prefix;
 155         struct name_decoration *decoration;
 156         const char *color_commit =
 157                 diff_get_color_opt(&opt->diffopt, DIFF_COMMIT);
 158         const char *color_reset =
 159                 decorate_get_color_opt(&opt->diffopt, DECORATION_NONE);
 160
 161         if (opt->show_source && commit->util)
 162                 printf("\t%s", (char *) commit->util);
 163         if (!opt->show_decorations)
 164                 return;
 165         decoration = lookup_decoration(&name_decoration, &commit->object);
 166         if (!decoration)
 167                 return;
 168         prefix = " (";
 169         while (decoration) {
 170                 printf("%s", prefix);
 171                 fputs(decorate_get_color_opt(&opt->diffopt, decoration->type),
 172                       stdout);
 173                 if (decoration->type == DECORATION_REF_TAG)
 174                         fputs("tag: ", stdout);
 175                 printf("%s", decoration->name);
 176                 fputs(color_reset, stdout);
 177                 fputs(color_commit, stdout);
 178                 prefix = ", ";
 179                 decoration = decoration->next;
 180         }
 181         putchar(')');
 182 }
 183
 184 /*
 185  * Search for "^[-A-Za-z]+: [^@]+@" pattern. It usually matches
 186  * Signed-off-by: and Acked-by: lines.
 187  */
 188 static int detect_any_signoff(char *letter, int size)
 189 {
 190         char *cp;
 191         int seen_colon = 0;
 192         int seen_at = 0;
 193         int seen_name = 0;
 194         int seen_head = 0;
 195
 196         cp = letter + size;
 197         while (letter <= --cp && *cp == '\n')
 198                 continue;
 199
 200         while (letter <= cp) {
 201                 char ch = *cp--;
 202                 if (ch == '\n')
 203                         break;
 204
 205                 if (!seen_at) {
 206                         if (ch == '@')
 207                                 seen_at = 1;
 208                         continue;
 209                 }
 210                 if (!seen_colon) {
 211                         if (ch == '@')
 212                                 return 0;
 213                         else if (ch == ':')
 214                                 seen_colon = 1;
 215                         else
 216                                 seen_name = 1;
 217                         continue;
 218                 }
 219                 if (('A' <= ch && ch <= 'Z') ||
 220                     ('a' <= ch && ch <= 'z') ||
 221                     ch == '-') {
 222                         seen_head = 1;
 223                         continue;
 224                 }
 225                 /* no empty last line doesn't match */
 226                 return 0;
 227         }
 228         return seen_head && seen_name;
 229 }
 230
 231 static void append_signoff(struct strbuf *sb, const char *signoff)
 232 {
 233         static const char signed_off_by[] = "Signed-off-by: ";
 234         size_t signoff_len = strlen(signoff);
 235         int has_signoff = 0;
 236         char *cp;
 237
 238         cp = sb->buf;
 239
 240         /* First see if we already have the sign-off by the signer */
 241         while ((cp = strstr(cp, signed_off_by))) {
 242
 243                 has_signoff = 1;
 244
 245                 cp += strlen(signed_off_by);
 246                 if (cp + signoff_len >= sb->buf + sb->len)
 247                         break;
 248                 if (strncmp(cp, signoff, signoff_len))
 249                         continue;
 250                 if (!isspace(cp[signoff_len]))
 251                         continue;
 252                 /* we already have him */
 253                 return;
 254         }
 255
 256         if (!has_signoff)
 257                 has_signoff = detect_any_signoff(sb->buf, sb->len);
 258
 259         if (!has_signoff)
 260                 strbuf_addch(sb, '\n');
 261
 262         strbuf_addstr(sb, signed_off_by);
 263         strbuf_add(sb, signoff, signoff_len);
 264         strbuf_addch(sb, '\n');
 265 }
 266
 267 static unsigned int digits_in_number(unsigned int number)
 268 {
 269         unsigned int i = 10, result = 1;
 270         while (i <= number) {
 271                 i *= 10;
 272                 result++;
 273         }
 274         return result;
 275 }
 276
 277 void get_patch_filename(struct commit *commit, int nr, const char *suffix,
 278                         struct strbuf *buf)
 279 {
 280         int suffix_len = strlen(suffix) + 1;
 281         int start_len = buf->len;
 282
 283         strbuf_addf(buf, commit ? "%04d-" : "%d", nr);
 284         if (commit) {
 285                 int max_len = start_len + FORMAT_PATCH_NAME_MAX - suffix_len;
 286                 struct pretty_print_context ctx = {0};
 287                 ctx.date_mode = DATE_NORMAL;
 288
 289                 format_commit_message(commit, "%f", buf, &ctx);
 290                 if (max_len < buf->len)
 291                         strbuf_setlen(buf, max_len);
 292                 strbuf_addstr(buf, suffix);
 293         }
 294 }
 295
 296 void log_write_email_headers(struct rev_info *opt, struct commit *commit,
 297                              const char **subject_p,
 298                              const char **extra_headers_p,
 299                              int *need_8bit_cte_p)
 300 {
 301         const char *subject = NULL;
 302         const char *extra_headers = opt->extra_headers;
 303         const char *name = sha1_to_hex(commit->object.sha1);
 304
 305         *need_8bit_cte_p = 0; /* unknown */
 306         if (opt->total > 0) {
 307                 static char buffer[64];
 308                 snprintf(buffer, sizeof(buffer),
 309                          "Subject: [%s%s%0*d/%d] ",
 310                          opt->subject_prefix,
 311                          *opt->subject_prefix ? " " : "",
 312                          digits_in_number(opt->total),
 313                          opt->nr, opt->total);
 314                 subject = buffer;
 315         } else if (opt->total == 0 && opt->subject_prefix && *opt->subject_prefix) {
 316                 static char buffer[256];
 317                 snprintf(buffer, sizeof(buffer),
 318                          "Subject: [%s] ",
 319                          opt->subject_prefix);
 320                 subject = buffer;
 321         } else {
 322                 subject = "Subject: ";
 323         }
 324
 325         printf("From %s Mon Sep 17 00:00:00 2001\n", name);
 326         graph_show_oneline(opt->graph);
 327         if (opt->message_id) {
 328                 printf("Message-Id: <%s>\n", opt->message_id);
 329                 graph_show_oneline(opt->graph);
 330         }
 331         if (opt->ref_message_ids && opt->ref_message_ids->nr > 0) {
 332                 int i, n;
 333                 n = opt->ref_message_ids->nr;
 334                 printf("In-Reply-To: <%s>\n", opt->ref_message_ids->items[n-1].string);
 335                 for (i = 0; i < n; i++)
 336                         printf("%s<%s>\n", (i > 0 ? "\t" : "References: "),
 337                                opt->ref_message_ids->items[i].string);
 338                 graph_show_oneline(opt->graph);
 339         }
 340         if (opt->mime_boundary) {
 341                 static char subject_buffer[1024];
 342                 static char buffer[1024];
 343                 struct strbuf filename =  STRBUF_INIT;
 344                 *need_8bit_cte_p = -1; /* NEVER */
 345                 snprintf(subject_buffer, sizeof(subject_buffer) - 1,
 346                          "%s"
 347                          "MIME-Version: 1.0\n"
 348                          "Content-Type: multipart/mixed;"
 349                          " boundary=\"%s%s\"\n"
 350                          "\n"
 351                          "This is a multi-part message in MIME "
 352                          "format.\n"
 353                          "--%s%s\n"
 354                          "Content-Type: text/plain; "
 355                          "charset=UTF-8; format=fixed\n"
 356                          "Content-Transfer-Encoding: 8bit\n\n",
 357                          extra_headers ? extra_headers : "",
 358                          mime_boundary_leader, opt->mime_boundary,
 359                          mime_boundary_leader, opt->mime_boundary);
 360                 extra_headers = subject_buffer;
 361
 362                 get_patch_filename(opt->numbered_files ? NULL : commit, opt->nr,
 363                                     opt->patch_suffix, &filename);
 364                 snprintf(buffer, sizeof(buffer) - 1,
 365                          "\n--%s%s\n"
 366                          "Content-Type: text/x-patch;"
 367                          " name=\"%s\"\n"
 368                          "Content-Transfer-Encoding: 8bit\n"
 369                          "Content-Disposition: %s;"
 370                          " filename=\"%s\"\n\n",
 371                          mime_boundary_leader, opt->mime_boundary,
 372                          filename.buf,
 373                          opt->no_inline ? "attachment" : "inline",
 374                          filename.buf);
 375                 opt->diffopt.stat_sep = buffer;
 376                 strbuf_release(&filename);
 377         }
 378         *subject_p = subject;
 379         *extra_headers_p = extra_headers;
 380 }
 381
 382 void show_log(struct rev_info *opt)
 383 {
 384         struct strbuf msgbuf = STRBUF_INIT;
 385         struct log_info *log = opt->loginfo;
 386         struct commit *commit = log->commit, *parent = log->parent;
 387         int abbrev_commit = opt->abbrev_commit ? opt->abbrev : 40;
 388         const char *extra_headers = opt->extra_headers;
 389         struct pretty_print_context ctx = {0};
 390
 391         opt->loginfo = NULL;
 392         ctx.show_notes = opt->show_notes;
 393         if (!opt->verbose_header) {
 394                 graph_show_commit(opt->graph);
 395
 396                 if (!opt->graph)
 397                         put_revision_mark(opt, commit);
 398                 fputs(find_unique_abbrev(commit->object.sha1, abbrev_commit), stdout);
 399                 if (opt->print_parents)
 400                         show_parents(commit, abbrev_commit);
 401                 show_decorations(opt, commit);
 402                 if (opt->graph && !graph_is_commit_finished(opt->graph)) {
 403                         putchar('\n');
 404                         graph_show_remainder(opt->graph);
 405                 }
 406                 putchar(opt->diffopt.line_termination);
 407                 return;
 408         }
 409
 410         /*
 411          * If use_terminator is set, we already handled any record termination
 412          * at the end of the last record.
 413          * Otherwise, add a diffopt.line_termination character before all
 414          * entries but the first.  (IOW, as a separator between entries)
 415          */
 416         if (opt->shown_one && !opt->use_terminator) {
 417                 /*
 418                  * If entries are separated by a newline, the output
 419                  * should look human-readable.  If the last entry ended
 420                  * with a newline, print the graph output before this
 421                  * newline.  Otherwise it will end up as a completely blank
 422                  * line and will look like a gap in the graph.
 423                  *
 424                  * If the entry separator is not a newline, the output is
 425                  * primarily intended for programmatic consumption, and we
 426                  * never want the extra graph output before the entry
 427                  * separator.
 428                  */
 429                 if (opt->diffopt.line_termination == '\n' &&
 430                     !opt->missing_newline)
 431                         graph_show_padding(opt->graph);
 432                 putchar(opt->diffopt.line_termination);
 433         }
 434         opt->shown_one = 1;
 435
 436         /*
 437          * If the history graph was requested,
 438          * print the graph, up to this commit's line
 439          */
 440         graph_show_commit(opt->graph);
 441
 442         /*
 443          * Print header line of header..
 444          */
 445
 446         if (opt->commit_format == CMIT_FMT_EMAIL) {
 447                 log_write_email_headers(opt, commit, &ctx.subject, &extra_headers,
 448                                         &ctx.need_8bit_cte);
 449         } else if (opt->commit_format != CMIT_FMT_USERFORMAT) {
 450                 fputs(diff_get_color_opt(&opt->diffopt, DIFF_COMMIT), stdout);
 451                 if (opt->commit_format != CMIT_FMT_ONELINE)
 452                         fputs("commit ", stdout);
 453
 454                 if (!opt->graph)
 455                         put_revision_mark(opt, commit);
 456                 fputs(find_unique_abbrev(commit->object.sha1, abbrev_commit),
 457                       stdout);
 458                 if (opt->print_parents)
 459                         show_parents(commit, abbrev_commit);
 460                 if (parent)
 461                         printf(" (from %s)",
 462                                find_unique_abbrev(parent->object.sha1,
 463                                                   abbrev_commit));
 464                 show_decorations(opt, commit);
 465                 printf("%s", diff_get_color_opt(&opt->diffopt, DIFF_RESET));
 466                 if (opt->commit_format == CMIT_FMT_ONELINE) {
 467                         putchar(' ');
 468                 } else {
 469                         putchar('\n');
 470                         graph_show_oneline(opt->graph);
 471                 }
 472                 if (opt->reflog_info) {
 473                         /*
 474                          * setup_revisions() ensures that opt->reflog_info
 475                          * and opt->graph cannot both be set,
 476                          * so we don't need to worry about printing the
 477                          * graph info here.
 478                          */
 479                         show_reflog_message(opt->reflog_info,
 480                                     opt->commit_format == CMIT_FMT_ONELINE,
 481                                     opt->date_mode_explicit ?
 482                                         opt->date_mode :
 483                                         DATE_NORMAL);
 484                         if (opt->commit_format == CMIT_FMT_ONELINE)
 485                                 return;
 486                 }
 487         }
 488
 489         if (!commit->buffer)
 490                 return;
 491
 492         /*
 493          * And then the pretty-printed message itself
 494          */
 495         if (ctx.need_8bit_cte >= 0)
 496                 ctx.need_8bit_cte = has_non_ascii(opt->add_signoff);
 497         ctx.date_mode = opt->date_mode;
 498         ctx.abbrev = opt->diffopt.abbrev;
 499         ctx.after_subject = extra_headers;
 500         ctx.preserve_subject = opt->preserve_subject;
 501         ctx.reflog_info = opt->reflog_info;
 502         ctx.fmt = opt->commit_format;
 503         pretty_print_commit(&ctx, commit, &msgbuf);
 504
 505         if (opt->add_signoff)
 506                 append_signoff(&msgbuf, opt->add_signoff);
 507         if (opt->show_log_size) {
 508                 printf("log size %i\n", (int)msgbuf.len);
 509                 graph_show_oneline(opt->graph);
 510         }
 511
 512         /*
 513          * Set opt->missing_newline if msgbuf doesn't
 514          * end in a newline (including if it is empty)
 515          */
 516         if (!msgbuf.len || msgbuf.buf[msgbuf.len - 1] != '\n')
 517                 opt->missing_newline = 1;
 518         else
 519                 opt->missing_newline = 0;
 520
 521         if (opt->graph)
 522                 graph_show_commit_msg(opt->graph, &msgbuf);
 523         else
 524                 fwrite(msgbuf.buf, sizeof(char), msgbuf.len, stdout);
 525         if (opt->use_terminator) {
 526                 if (!opt->missing_newline)
 527                         graph_show_padding(opt->graph);
 528                 putchar('\n');
 529         }
 530
 531         strbuf_release(&msgbuf);
 532 }
 533
 534 int log_tree_diff_flush(struct rev_info *opt)
 535 {
 536         diffcore_std(&opt->diffopt);
 537
 538         if (diff_queue_is_empty()) {
 539                 int saved_fmt = opt->diffopt.output_format;
 540                 opt->diffopt.output_format = DIFF_FORMAT_NO_OUTPUT;
 541                 diff_flush(&opt->diffopt);
 542                 opt->diffopt.output_format = saved_fmt;
 543                 return 0;
 544         }
 545
 546         if (opt->loginfo && !opt->no_commit_id) {
 547                 /* When showing a verbose header (i.e. log message),
 548                  * and not in --pretty=oneline format, we would want
 549                  * an extra newline between the end of log and the
 550                  * output for readability.
 551                  */
 552                 show_log(opt);
 553                 if ((opt->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT) &&
 554                     opt->verbose_header &&
 555                     opt->commit_format != CMIT_FMT_ONELINE) {
 556                         int pch = DIFF_FORMAT_DIFFSTAT | DIFF_FORMAT_PATCH;
 557                         if ((pch & opt->diffopt.output_format) == pch)
 558                                 printf("---");
 559                         if (opt->diffopt.output_prefix) {
 560                                 struct strbuf *msg = NULL;
 561                                 msg = opt->diffopt.output_prefix(&opt->diffopt,
 562                                         opt->diffopt.output_prefix_data);
 563                                 fwrite(msg->buf, msg->len, 1, stdout);
 564                         }
 565                         putchar('\n');
 566                 }
 567         }
 568         diff_flush(&opt->diffopt);
 569         return 1;
 570 }
 571
 572 static int do_diff_combined(struct rev_info *opt, struct commit *commit)
 573 {
 574         unsigned const char *sha1 = commit->object.sha1;
 575
 576         diff_tree_combined_merge(sha1, opt->dense_combined_merges, opt);
 577         return !opt->loginfo;
 578 }
 579
 580 /*
 581  * Show the diff of a commit.
 582  *
 583  * Return true if we printed any log info messages
 584  */
 585 static int log_tree_diff(struct rev_info *opt, struct commit *commit, struct log_info *log)
 586 {
 587         int showed_log;
 588         struct commit_list *parents;
 589         unsigned const char *sha1 = commit->object.sha1;
 590
 591         if (!opt->diff && !DIFF_OPT_TST(&opt->diffopt, EXIT_WITH_STATUS))
 592                 return 0;
 593
 594         /* Root commit? */
 595         parents = commit->parents;
 596         if (!parents) {
 597                 if (opt->show_root_diff) {
 598                         diff_root_tree_sha1(sha1, "", &opt->diffopt);
 599                         log_tree_diff_flush(opt);
 600                 }
 601                 return !opt->loginfo;
 602         }
 603
 604         /* More than one parent? */
 605         if (parents && parents->next) {
 606                 if (opt->ignore_merges)
 607                         return 0;
 608                 else if (opt->combine_merges)
 609                         return do_diff_combined(opt, commit);
 610                 else if (opt->first_parent_only) {
 611                         /*
 612                          * Generate merge log entry only for the first
 613                          * parent, showing summary diff of the others
 614                          * we merged _in_.
 615                          */
 616                         diff_tree_sha1(parents->item->object.sha1, sha1, "", &opt->diffopt);
 617                         log_tree_diff_flush(opt);
 618                         return !opt->loginfo;
 619                 }
 620
 621                 /* If we show individual diffs, show the parent info */
 622                 log->parent = parents->item;
 623         }
 624
 625         showed_log = 0;
 626         for (;;) {
 627                 struct commit *parent = parents->item;
 628
 629                 diff_tree_sha1(parent->object.sha1, sha1, "", &opt->diffopt);
 630                 log_tree_diff_flush(opt);
 631
 632                 showed_log |= !opt->loginfo;
 633
 634                 /* Set up the log info for the next parent, if any.. */
 635                 parents = parents->next;
 636                 if (!parents)
 637                         break;
 638                 log->parent = parents->item;
 639                 opt->loginfo = log;
 640         }
 641         return showed_log;
 642 }
 643
 644 int log_tree_commit(struct rev_info *opt, struct commit *commit)
 645 {
 646         struct log_info log;
 647         int shown;
 648
 649         log.commit = commit;
 650         log.parent = NULL;
 651         opt->loginfo = &log;
 652
 653         shown = log_tree_diff(opt, commit, &log);
 654         if (!shown && opt->loginfo && opt->always_show_header) {
 655                 log.parent = NULL;
 656                 show_log(opt);
 657                 shown = 1;
 658         }
 659         opt->loginfo = NULL;
 660         maybe_flush_or_die(stdout, "stdout");
 661         return shown;
 662 }