Merge branch 'jk/blame-first-parent'

"git blame --first-parent v1.0..v2.0" was not rejected but did not
limit the blame to commits on the first parent chain.

* jk/blame-first-parent:
blame: handle --first-parent

diff --combined builtin/blame.c
index 6fd1a63fc7e45464ebb85d339f464f55f350ac8d,e024f43aeedc2c159943e02882387a03afb335d7..01ea7707875e167a666aedfa412c3bf24d728675
--- 1/builtin/blame.c
--- 2/builtin/blame.c
+++ b/builtin/blame.c
@@@ -6,7 -6,6 +6,7 @@@
   */
  
  #include "cache.h"
 +#include "refs.h"
  #include "builtin.h"
  #include "blob.h"
  #include "commit.h"
@@@ -51,7 -50,7 +51,7 @@@ static int xdl_opts
  static int abbrev = -1;
  static int no_whole_file_rename;
  
 -static enum date_mode blame_date_mode = DATE_ISO8601;
 +static struct date_mode blame_date_mode = { DATE_ISO8601 };
  static size_t blame_date_width;
  
  static struct string_list mailmap;
@@@ -1366,8 -1365,15 +1366,15 @@@ static void pass_whole_blame(struct sco
   */
  static struct commit_list *first_scapegoat(struct rev_info *revs, struct commit *commit)
  {
-       if (!reverse)
+       if (!reverse) {
+               if (revs->first_parent_only &&
+                   commit->parents &&
+                   commit->parents->next) {
+                       free_commit_list(commit->parents->next);
+                       commit->parents->next = NULL;
+               }
                return commit->parents;
+       }
        return lookup_decoration(&revs->children, &commit->object);
  }
  
@@@ -1828,7 -1834,7 +1835,7 @@@ static const char *format_time(unsigne
                size_t time_width;
                int tz;
                tz = atoi(tz_str);
 -              time_str = show_date(time, tz, blame_date_mode);
 +              time_str = show_date(time, tz, &blame_date_mode);
                strbuf_addstr(&time_buf, time_str);
                /*
                 * Add space paddings to time_buf to display a fixed width
@@@ -2188,7 -2194,7 +2195,7 @@@ static int git_blame_config(const char 
        if (!strcmp(var, "blame.date")) {
                if (!value)
                        return config_error_nonbool(var);
 -              blame_date_mode = parse_date_format(value);
 +              parse_date_format(value, &blame_date_mode);
                return 0;
        }
  
@@@ -2227,19 -2233,20 +2234,19 @@@ static struct commit_list **append_pare
  static void append_merge_parents(struct commit_list **tail)
  {
        int merge_head;
 -      const char *merge_head_file = git_path("MERGE_HEAD");
        struct strbuf line = STRBUF_INIT;
  
 -      merge_head = open(merge_head_file, O_RDONLY);
 +      merge_head = open(git_path_merge_head(), O_RDONLY);
        if (merge_head < 0) {
                if (errno == ENOENT)
                        return;
 -              die("cannot open '%s' for reading", merge_head_file);
 +              die("cannot open '%s' for reading", git_path_merge_head());
        }
  
        while (!strbuf_getwholeline_fd(&line, merge_head, '\n')) {
                unsigned char sha1[20];
                if (line.len < 40 || get_sha1_hex(line.buf, sha1))
 -                      die("unknown line in '%s': %s", merge_head_file, line.buf);
 +                      die("unknown line in '%s': %s", git_path_merge_head(), line.buf);
                tail = append_parent(tail, sha1);
        }
        close(merge_head);
@@@ -2569,13 -2576,13 +2576,13 @@@ parse_done
  
        if (cmd_is_annotate) {
                output_option |= OUTPUT_ANNOTATE_COMPAT;
 -              blame_date_mode = DATE_ISO8601;
 +              blame_date_mode.type = DATE_ISO8601;
        } else {
                blame_date_mode = revs.date_mode;
        }
  
        /* The maximum width used to show the dates */
 -      switch (blame_date_mode) {
 +      switch (blame_date_mode.type) {
        case DATE_RFC2822:
                blame_date_width = sizeof("Thu, 19 Oct 2006 16:00:04 -0700");
                break;
@@@ -2600,12 -2607,10 +2607,12 @@@
                   fewer display columns. */
                blame_date_width = utf8_strwidth(_("4 years, 11 months ago")) + 1; /* add the null */
                break;
 -      case DATE_LOCAL:
        case DATE_NORMAL:
                blame_date_width = sizeof("Thu Oct 19 16:00:04 2006 -0700");
                break;
 +      case DATE_STRFTIME:
 +              blame_date_width = strlen(show_date(0, 0, &blame_date_mode)) + 1; /* add the null */
 +              break;
        }
        blame_date_width -= 1; /* strip the null */
  
@@@ -2679,6 -2684,8 +2686,8 @@@
        }
        else if (contents_from)
                die("--contents and --children do not blend well.");
+       else if (revs.first_parent_only)
+               die("combining --first-parent and --reverse is not supported");
        else {
                final_commit_name = prepare_initial(&sb);
                sb.commits.compare = compare_commits_by_reverse_commit_date;