shortlog: support arbitrary commit format `--group`s

In addition to generating a shortlog based on committer, author, or the
identity in one or more specified trailers, it can be useful to generate
a shortlog based on an arbitrary commit format.

This can be used, for example, to generate a distribution of commit
activity over time, like so:

    $ git shortlog --group='%cd' --date='format:%Y-%m' -s v2.37.0..
       117  2022-06
       274  2022-07
       324  2022-08
       263  2022-09
         7  2022-10

Arbitrary commit formats can be used. In fact, `git shortlog`'s default
behavior (to count by commit authors) can be emulated as follows:

    $ git shortlog --group='%aN <%aE>' ...

and future patches will make the default behavior (as well as
`--committer`, and `--group=trailer:<trailer>`) special cases of the
more flexible `--group` option.

Note also that the SHORTLOG_GROUP_FORMAT enum value is used only to
designate that `--group:<format>` is in use when in stdin mode to
declare that the combination is invalid.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-shortlog.txt b/Documentation/git-shortlog.txt
index 9ed9d6a9e7d6745ed33cc4006d541699f237fe10..7d0277d033d60227cee0b24a4c8747dfa892f4e7 100644 (file)
--- a/Documentation/git-shortlog.txt
+++ b/Documentation/git-shortlog.txt
@@ -50,7 +50,7 @@ OPTIONS
 --date=<format>::
        Show dates formatted according to the given date string. (See
        the `--date` option in the "Commit Formatting" section of
-       linkgit:git-log[1]).
+       linkgit:git-log[1]). Useful with `--group=format:<format>`.
 
 --group=<type>::
        Group commits based on `<type>`. If no `--group` option is
@@ -64,6 +64,9 @@ OPTIONS
    example, if your project uses `Reviewed-by` trailers, you might want
    to see who has been reviewing with
    `git shortlog -ns --group=trailer:reviewed-by`.
+ - `format:<format>`, any string accepted by the `--format` option of
+   'git log'. (See the "PRETTY FORMATS" section of
+   linkgit:git-log[1].)
 +
 Note that commits that do not include the trailer will not be counted.
 Likewise, commits with multiple trailers (e.g., multiple signoffs) may

diff --git a/builtin/shortlog.c b/builtin/shortlog.c
index d0645769d7ac512a3b07fb2300de945657cb9d92..f3b237c5ff08e07a9c37e12c63c34886aad8ac8b 100644 (file)
--- a/builtin/shortlog.c
+++ b/builtin/shortlog.c
@@ -133,6 +133,8 @@ static void read_from_stdin(struct shortlog *log)
                break;
        case SHORTLOG_GROUP_TRAILER:
                die(_("using %s with stdin is not supported"), "--group=trailer");
+       case SHORTLOG_GROUP_FORMAT:
+               die(_("using %s with stdin is not supported"), "--group=format");
        default:
                BUG("unhandled shortlog group");
        }
@@ -203,6 +205,32 @@ static void insert_records_from_trailers(struct shortlog *log,
        unuse_commit_buffer(commit, commit_buffer);
 }
 
+static int shortlog_needs_dedup(const struct shortlog *log)
+{
+       return HAS_MULTI_BITS(log->groups) || log->format.nr > 1 || log->trailers.nr;
+}
+
+static void insert_records_from_format(struct shortlog *log,
+                                      struct strset *dups,
+                                      struct commit *commit,
+                                      struct pretty_print_context *ctx,
+                                      const char *oneline)
+{
+       struct strbuf buf = STRBUF_INIT;
+       struct string_list_item *item;
+
+       for_each_string_list_item(item, &log->format) {
+               strbuf_reset(&buf);
+
+               format_commit_message(commit, item->string, &buf, ctx);
+
+               if (!shortlog_needs_dedup(log) || strset_add(dups, buf.buf))
+                       insert_one_record(log, buf.buf, oneline);
+       }
+
+       strbuf_release(&buf);
+}
+
 void shortlog_add_commit(struct shortlog *log, struct commit *commit)
 {
        struct strbuf ident = STRBUF_INIT;
@@ -244,6 +272,7 @@ void shortlog_add_commit(struct shortlog *log, struct commit *commit)
                        insert_one_record(log, ident.buf, oneline_str);
        }
        insert_records_from_trailers(log, &dups, commit, &ctx, oneline_str);
+       insert_records_from_format(log, &dups, commit, &ctx, oneline_str);
 
        strset_clear(&dups);
        strbuf_release(&ident);
@@ -315,6 +344,7 @@ static int parse_group_option(const struct option *opt, const char *arg, int uns
        if (unset) {
                log->groups = 0;
                string_list_clear(&log->trailers, 0);
+               string_list_clear(&log->format, 0);
        } else if (!strcasecmp(arg, "author"))
                log->groups |= SHORTLOG_GROUP_AUTHOR;
        else if (!strcasecmp(arg, "committer"))
@@ -322,8 +352,15 @@ static int parse_group_option(const struct option *opt, const char *arg, int uns
        else if (skip_prefix(arg, "trailer:", &field)) {
                log->groups |= SHORTLOG_GROUP_TRAILER;
                string_list_append(&log->trailers, field);
-       } else
+       } else if (skip_prefix(arg, "format:", &field)) {
+               log->groups |= SHORTLOG_GROUP_FORMAT;
+               string_list_append(&log->format, field);
+       } else if (strchr(arg, '%')) {
+               log->groups |= SHORTLOG_GROUP_FORMAT;
+               string_list_append(&log->format, arg);
+       } else {
                return error(_("unknown group type: %s"), arg);
+       }
 
        return 0;
 }
@@ -341,6 +378,7 @@ void shortlog_init(struct shortlog *log)
        log->in2 = DEFAULT_INDENT2;
        log->trailers.strdup_strings = 1;
        log->trailers.cmp = strcasecmp;
+       log->format.strdup_strings = 1;
 }
 
 int cmd_shortlog(int argc, const char **argv, const char *prefix)
@@ -481,4 +519,5 @@ void shortlog_output(struct shortlog *log)
        log->list.strdup_strings = 1;
        string_list_clear(&log->list, 1);
        clear_mailmap(&log->mailmap);
+       string_list_clear(&log->format, 0);
 }

diff --git a/shortlog.h b/shortlog.h
index dc388dd459749392a70a9be8138d1d4c2f1b667e..4850a8c30f9e3f429237bce73e31f3d85f6ed59a 100644 (file)
--- a/shortlog.h
+++ b/shortlog.h
@@ -22,8 +22,10 @@ struct shortlog {
                SHORTLOG_GROUP_AUTHOR = (1 << 0),
                SHORTLOG_GROUP_COMMITTER = (1 << 1),
                SHORTLOG_GROUP_TRAILER = (1 << 2),
+               SHORTLOG_GROUP_FORMAT = (1 << 3),
        } groups;
        struct string_list trailers;
+       struct string_list format;
 
        int email;
        struct string_list mailmap;

diff --git a/t/t4201-shortlog.sh b/t/t4201-shortlog.sh
index 7547da539dbb641fca0a8ec67449db938a809573..8e4effebdb71c6d44f9c7d272ad5c3cd44d0b1e8 100755 (executable)
--- a/t/t4201-shortlog.sh
+++ b/t/t4201-shortlog.sh
@@ -244,6 +244,26 @@ test_expect_success 'shortlog --group=trailer:signed-off-by' '
        test_cmp expect actual
 '
 
+test_expect_success 'shortlog --group=format' '
+       git shortlog -s --date="format:%Y" --group="format:%cN (%cd)" \
+               HEAD >actual &&
+       cat >expect <<-\EOF &&
+            4  C O Mitter (2005)
+            1  Sin Nombre (2005)
+       EOF
+       test_cmp expect actual
+'
+
+test_expect_success 'shortlog --group=<format> DWIM' '
+       git shortlog -s --date="format:%Y" --group="%cN (%cd)" HEAD >actual &&
+       test_cmp expect actual
+'
+
+test_expect_success 'shortlog bogus --group' '
+       test_must_fail git shortlog --group=bogus HEAD 2>err &&
+       grep "unknown group type" err
+'
+
 test_expect_success 'trailer idents are split' '
        cat >expect <<-\EOF &&
             2  C O Mitter
@@ -326,6 +346,18 @@ test_expect_success 'shortlog can match multiple groups' '
        test_cmp expect actual
 '
 
+test_expect_success 'shortlog can match multiple format groups' '
+       GIT_COMMITTER_NAME="$GIT_AUTHOR_NAME" \
+               git commit --allow-empty -m "identical names" &&
+       test_tick &&
+       cat >expect <<-\EOF &&
+            2  A U Thor
+            1  C O Mitter
+       EOF
+       git shortlog -ns --group="%cn" --group="%an" -2 HEAD >actual &&
+       test_cmp expect actual
+'
+
 test_expect_success 'set up option selection tests' '
        git commit --allow-empty -F - <<-\EOF
        subject