[PATCH] [GSOC] commit: provides multiple common signatures

["ZheNing Hu via GitGitGadget" <gitgitgadget@gmail.com>]

From: ZheNing Hu <adlternative@gmail.com>

Similar to "Helped-by", "Reported-by", "Reviewed-by", "Mentored-by"
these signatures are often seen in git commit messages. After
referring to the simple implementation of `commit --signoff`
and `send-email -cc=" commiter <email>"`, I am considering
whether to provide multiple signature parameters from the
command line. I think this might help maintainers and
developers directly uses the shell to provide these signatures
instead of multiple times repetitive writing those trailers
each time.

To achieve this goal, i refactored the `append_signoff` design and
provided `append_message` and `append_message_string_list` interfaces,
providing new ways to generate those various signatures.

Users now can use `commit -H "helper <eamil>"` to generate "Helped-by" trailer,
`commit -R "reviewer <eamil>"` to generate "Reviewed-by" trailer,
`commit -r "reporter <eamil> "`to generate "Reported-by" trailer,
`commit -M "mentor <eamil>"` to generate "Mentored-by" trailer.

Signed-off-by: ZheNing Hu <adlternative@gmail.com>
---
    [GSOC] commit: provides multiple signatures from command line
    
    I don’t know if my idea will satisfy everyone, I'm also thinking about
    whether we can provide a more generalized version (I think this idea can
    be extended: because users and developers have other signature methods
    that they want, such as "Based-on-patch-by") I hope someone can give me
    pointers (on the correctness of ideas or codes)

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-901%2Fadlternative%2Fcommit-with-multiple-signatures-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-901/adlternative/commit-with-multiple-signatures-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/901

 Documentation/git-commit.txt |  24 +++++++-
 builtin/commit.c             |  63 +++++++++++++++++++++
 sequencer.c                  |  40 +++++++++----
 sequencer.h                  |   4 ++
 t/t7502-commit-porcelain.sh  | 106 +++++++++++++++++++++++++++++++++++
 5 files changed, 226 insertions(+), 11 deletions(-)

diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt
index 17150fa7eabe..e1b528d70c1a 100644
--- a/Documentation/git-commit.txt
+++ b/Documentation/git-commit.txt
@@ -14,7 +14,9 @@ SYNOPSIS
 	   [--allow-empty-message] [--no-verify] [-e] [--author=<author>]
 	   [--date=<date>] [--cleanup=<mode>] [--[no-]status]
 	   [-i | -o] [--pathspec-from-file=<file> [--pathspec-file-nul]]
-	   [-S[<keyid>]] [--] [<pathspec>...]
+	   [-S[<keyid>]] [--] [<pathspec>...] [(-H|--helped-by)=<address>...]
+	   [(-R|--reviewed-by)=<address>...] [(-r|--reported-by)=<address>...]
+	   [(-M|--mentored)=<address>...]
 
 DESCRIPTION
 -----------
@@ -166,6 +168,26 @@ The `-m` option is mutually exclusive with `-c`, `-C`, and `-F`.
 
 include::signoff-option.txt[]
 
+-H=<address>...::
+--helped-by=<address>...::
+	Add one or more `Helped-by` trailer by the committer at the end of the commit
+	log message.
+
+-R=<address>...::
+--reviewed-by=<address>...::
+	Add one or more `Reviewed-by` trailer by the committer at the end of the commit
+	log message.
+
+-r=<address>...::
+--reported-by=<address>...::
+	Add one or more `Reported-by` trailer by the committer at the end of the commit
+	log message.
+
+-M=<address>...::
+--mentored-by=<address>...::
+	Add one or more `Mentored-by` trailer by the committer at the end of the commit
+	log message.
+
 -n::
 --no-verify::
 	This option bypasses the pre-commit and commit-msg hooks.
diff --git a/builtin/commit.c b/builtin/commit.c
index 739110c5a7f6..4b312af03181 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -113,6 +113,10 @@ static int config_commit_verbose = -1; /* unspecified */
 static int no_post_rewrite, allow_empty_message, pathspec_file_nul;
 static char *untracked_files_arg, *force_date, *ignore_submodule_arg, *ignored_arg;
 static char *sign_commit, *pathspec_from_file;
+static struct string_list helped_by = STRING_LIST_INIT_NODUP;
+static struct string_list mentored_by = STRING_LIST_INIT_NODUP;
+static struct string_list reviewed_by = STRING_LIST_INIT_NODUP;
+static struct string_list reported_by = STRING_LIST_INIT_NODUP;
 
 /*
  * The default commit message cleanup mode will remove the lines
@@ -829,6 +833,20 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 	if (signoff)
 		append_signoff(&sb, ignore_non_trailer(sb.buf, sb.len), 0);
 
+	if(helped_by.items)
+		append_message_string_list(&sb, "Helped-by: ", &helped_by, ignore_non_trailer(sb.buf, sb.len), 0);
+	if(reviewed_by.items)
+		append_message_string_list(&sb, "Reviewed-by: ", &reviewed_by, ignore_non_trailer(sb.buf, sb.len), 0);
+	if(reported_by.items)
+		append_message_string_list(&sb, "Reported-by: ", &reported_by, ignore_non_trailer(sb.buf, sb.len), 0);
+	if(mentored_by.items)
+		append_message_string_list(&sb, "Mentored-by: ", &mentored_by, ignore_non_trailer(sb.buf, sb.len), 0);
+
+	string_list_clear(&helped_by, 0);
+	string_list_clear(&reviewed_by, 0);
+	string_list_clear(&reported_by, 0);
+	string_list_clear(&mentored_by, 0);
+
 	if (fwrite(sb.buf, 1, sb.len, s->fp) < sb.len)
 		die_errno(_("could not write commit template"));
 
@@ -1490,6 +1508,42 @@ static int git_commit_config(const char *k, const char *v, void *cb)
 	return git_status_config(k, v, s);
 }
 
+static int help_callback(const struct option *opt, const char *arg, int unset)
+{
+	if (unset)
+		string_list_clear(&helped_by, 0);
+	else
+		string_list_append(&helped_by, arg);
+	return 0;
+}
+
+static int review_callback(const struct option *opt, const char *arg, int unset)
+{
+	if (unset)
+		string_list_clear(&reviewed_by, 0);
+	else
+		string_list_append(&reviewed_by, arg);
+	return 0;
+}
+
+static int report_callback(const struct option *opt, const char *arg, int unset)
+{
+	if (unset)
+		string_list_clear(&reported_by, 0);
+	else
+		string_list_append(&reported_by, arg);
+	return 0;
+}
+
+static int mentor_callback(const struct option *opt, const char *arg, int unset)
+{
+	if (unset)
+		string_list_clear(&mentored_by, 0);
+	else
+		string_list_append(&mentored_by, arg);
+	return 0;
+}
+
 int cmd_commit(int argc, const char **argv, const char *prefix)
 {
 	static struct wt_status s;
@@ -1507,6 +1561,10 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		OPT_STRING(0, "fixup", &fixup_message, N_("commit"), N_("use autosquash formatted message to fixup specified commit")),
 		OPT_STRING(0, "squash", &squash_message, N_("commit"), N_("use autosquash formatted message to squash specified commit")),
 		OPT_BOOL(0, "reset-author", &renew_authorship, N_("the commit is authored by me now (used with -C/-c/--amend)")),
+		OPT_CALLBACK('H', "helped-by", NULL, N_("email"), N_("add a Helped-by trailer"), help_callback),
+		OPT_CALLBACK('r', "reported-by", NULL, N_("email"), N_("add a Reported-by trailer"), report_callback),
+		OPT_CALLBACK('R', "reviewed-by", NULL, N_("email"), N_("add a Reviewed-by trailer"), review_callback),
+		OPT_CALLBACK('M', "mentored-by", NULL, N_("email"), N_("add a Mentored-by trailer"), mentor_callback),
 		OPT_BOOL('s', "signoff", &signoff, N_("add a Signed-off-by trailer")),
 		OPT_FILENAME('t', "template", &template_file, N_("use specified template file")),
 		OPT_BOOL('e', "edit", &edit_flag, N_("force edit of commit")),
@@ -1561,6 +1619,11 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	struct commit_extra_header *extra = NULL;
 	struct strbuf err = STRBUF_INIT;
 
+	helped_by.strdup_strings = 1;
+	reviewed_by.strdup_strings = 1;
+	reported_by.strdup_strings = 1;
+	mentored_by.strdup_strings = 1;
+
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage_with_options(builtin_commit_usage, builtin_commit_options);
 
diff --git a/sequencer.c b/sequencer.c
index d2332d3e1787..528daf9df252 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -4668,16 +4668,12 @@ int sequencer_pick_revisions(struct repository *r,
 	return res;
 }
 
-void append_signoff(struct strbuf *msgbuf, size_t ignore_footer, unsigned flag)
+void append_message(struct strbuf *msgbuf, struct strbuf *sob,
+			size_t ignore_footer, unsigned flag)
 {
 	unsigned no_dup_sob = flag & APPEND_SIGNOFF_DEDUP;
-	struct strbuf sob = STRBUF_INIT;
 	int has_footer;
 
-	strbuf_addstr(&sob, sign_off_header);
-	strbuf_addstr(&sob, fmt_name(WANT_COMMITTER_IDENT));
-	strbuf_addch(&sob, '\n');
-
 	if (!ignore_footer)
 		strbuf_complete_line(msgbuf);
 
@@ -4685,11 +4681,11 @@ void append_signoff(struct strbuf *msgbuf, size_t ignore_footer, unsigned flag)
 	 * If the whole message buffer is equal to the sob, pretend that we
 	 * found a conforming footer with a matching sob
 	 */
-	if (msgbuf->len - ignore_footer == sob.len &&
-	    !strncmp(msgbuf->buf, sob.buf, sob.len))
+	if (msgbuf->len - ignore_footer == sob->len &&
+	    !strncmp(msgbuf->buf, sob->buf, sob->len))
 		has_footer = 3;
 	else
-		has_footer = has_conforming_footer(msgbuf, &sob, ignore_footer);
+		has_footer = has_conforming_footer(msgbuf, sob, ignore_footer);
 
 	if (!has_footer) {
 		const char *append_newlines = NULL;
@@ -4723,8 +4719,32 @@ void append_signoff(struct strbuf *msgbuf, size_t ignore_footer, unsigned flag)
 
 	if (has_footer != 3 && (!no_dup_sob || has_footer != 2))
 		strbuf_splice(msgbuf, msgbuf->len - ignore_footer, 0,
-				sob.buf, sob.len);
+				sob->buf, sob->len);
+}
+
+void append_signoff(struct strbuf *msgbuf, size_t ignore_footer, unsigned flag)
+{
+	struct strbuf sob = STRBUF_INIT;
+	strbuf_addstr(&sob, sign_off_header);
+	strbuf_addstr(&sob, fmt_name(WANT_COMMITTER_IDENT));
+	strbuf_addch(&sob, '\n');
+	append_message(msgbuf, &sob, ignore_footer, flag);
+	strbuf_release(&sob);
+}
 
+void append_message_string_list(struct strbuf *msgbuf, const char *header,
+		struct string_list *sobs, size_t ignore_footer, unsigned flag) {
+	int i;
+	struct strbuf sob = STRBUF_INIT;
+
+	for ( i = 0; i < sobs->nr; i++)
+	{
+		strbuf_addstr(&sob, header);
+		strbuf_addstr(&sob, sobs->items[i].string);
+		strbuf_addch(&sob, '\n');
+		append_message(msgbuf, &sob, ignore_footer, flag);
+		strbuf_reset(&sob);
+	}
 	strbuf_release(&sob);
 }
 
diff --git a/sequencer.h b/sequencer.h
index f8b2e4ab8527..b24e274f4c62 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -174,6 +174,10 @@ int todo_list_rearrange_squash(struct todo_list *todo_list);
  * and the new signoff will be spliced into the buffer before those bytes.
  */
 void append_signoff(struct strbuf *msgbuf, size_t ignore_footer, unsigned flag);
+void append_message(struct strbuf *msgbuf, struct strbuf *sob,
+		size_t ignore_footer, unsigned flag);
+void append_message_string_list(struct strbuf *msgbuf, const char*header,
+		struct string_list *sobs, size_t ignore_footer, unsigned flag);
 
 void append_conflicts_hint(struct index_state *istate,
 		struct strbuf *msgbuf, enum commit_msg_cleanup_mode cleanup_mode);
diff --git a/t/t7502-commit-porcelain.sh b/t/t7502-commit-porcelain.sh
index 6396897cc818..40823152a51c 100755
--- a/t/t7502-commit-porcelain.sh
+++ b/t/t7502-commit-porcelain.sh
@@ -154,6 +154,112 @@ test_expect_success 'sign off' '
 
 '
 
+test_expect_success 'helped-by' '
+
+	>file1 &&
+	git add file1 &&
+	git commit --helped-by="foo <bar@frotz>" \
+	--helped-by="foo2 <bar2@frotz>" -m "thank you" &&
+	git cat-file commit HEAD >commit.msg &&
+	sed -ne "s/Helped-by: //p" commit.msg >actual &&
+	cat >expected <<-\EOF &&
+	foo <bar@frotz>
+	foo2 <bar2@frotz>
+	EOF
+	test_cmp expected actual
+
+'
+
+test_expect_success 'reported-by' '
+
+	>file2 &&
+	git add file2 &&
+	git commit --reported-by="foo <bar@frotz>" \
+	--reported-by="foo2 <bar2@frotz>" -m "thank you" &&
+	git cat-file commit HEAD >commit.msg &&
+	sed -ne "s/Reported-by: //p" commit.msg >actual &&
+	cat >expected <<-\EOF &&
+	foo <bar@frotz>
+	foo2 <bar2@frotz>
+	EOF
+	test_cmp expected actual
+
+'
+
+test_expect_success 'reviewed-by' '
+
+	>file3 &&
+	git add file3 &&
+	git commit --reviewed-by="foo <bar@frotz>" \
+	--reviewed-by="foo2 <bar2@frotz>" -m "thank you" &&
+	git cat-file commit HEAD >commit.msg &&
+	sed -ne "s/Reviewed-by: //p" commit.msg >actual &&
+	cat >expected <<-\EOF &&
+	foo <bar@frotz>
+	foo2 <bar2@frotz>
+	EOF
+	test_cmp expected actual
+
+'
+
+test_expect_success 'mentored-by' '
+
+	>file4 &&
+	git add file4 &&
+	git commit --mentored-by="foo <bar@frotz>" \
+	--mentored-by="foo2 <bar2@frotz>" -m "thank you" &&
+	git cat-file commit HEAD >commit.msg &&
+	sed -ne "s/Mentored-by: //p" commit.msg >actual &&
+	cat >expected <<-\EOF &&
+	foo <bar@frotz>
+	foo2 <bar2@frotz>
+	EOF
+	test_cmp expected actual
+
+'
+
+test_expect_success 'multiple signatures' '
+
+	>file5 &&
+	git add file5 &&
+	git commit --helped-by="foo <bar@frotz>" \
+	--reviewed-by="foo2 <bar2@frotz>" \
+	--mentored-by="foo3 <bar3@frotz>" \
+	--reported-by="foo4 <bar4@frotz>" -s -m "thank you" &&
+	git cat-file commit HEAD >commit.msg &&
+	sed -e "1,7d" commit.msg >actual &&
+	cat >expected <<-\EOF &&
+	Signed-off-by: C O Mitter <committer@example.com>
+	Helped-by: foo <bar@frotz>
+	Reviewed-by: foo2 <bar2@frotz>
+	Reported-by: foo4 <bar4@frotz>
+	Mentored-by: foo3 <bar3@frotz>
+	EOF
+	test_cmp expected actual
+
+'
+
+test_expect_success 'multiple signatures (use abbreviations)' '
+
+	>file6 &&
+	git add file6 &&
+	git commit -H "foo <bar@frotz>" \
+	-R "foo2 <bar2@frotz>" \
+	-M "foo3 <bar3@frotz>" \
+	-r "foo4 <bar4@frotz>" -s -m "thank you" &&
+	git cat-file commit HEAD >commit.msg &&
+	sed -e "1,7d" commit.msg >actual &&
+	cat >expected <<-\EOF &&
+	Signed-off-by: C O Mitter <committer@example.com>
+	Helped-by: foo <bar@frotz>
+	Reviewed-by: foo2 <bar2@frotz>
+	Reported-by: foo4 <bar4@frotz>
+	Mentored-by: foo3 <bar3@frotz>
+	EOF
+	test_cmp expected actual
+
+'
+
 test_expect_success 'multiple -m' '
 
 	>negative &&

base-commit: 13d7ab6b5d7929825b626f050b62a11241ea4945
-- 
gitgitgadget