[PATCH 3/3] format-patch: add commitListFormat config

[Mirko Faina <mroik@delayed.space>]

Using "--cover-letter" we can tell format-patch to generate a cover
letter, in this cover letter there's a list of commits included in the
patch series and the format is specified by the "--cover-letter-format"
option. Would be useful if this format could be configured from the
config file instead of always needing to pass it from the command line.

Teach format-patch how to read the format spec for the cover letter from
the config files. The variable it should look for is called
"commitListFormat".

If commitListFormat is set but not string is passed, it will use the
"%s" format spec, if a string is passed will use it as a format spec, if
it is not set at all it will default to the shortlog format.

Signed-off-by: Mirko Faina <mroik@delayed.space>
---
 builtin/log.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/builtin/log.c b/builtin/log.c
index 80ec79efe8..7f41c83e18 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -886,6 +886,7 @@ struct format_config {
 	char *signature;
 	char *signature_file;
 	enum cover_setting config_cover_letter;
+	char* fmt_cover_letter_commit_list;
 	char *config_output_directory;
 	enum cover_from_description cover_from_description_mode;
 	int show_notes;
@@ -930,6 +931,7 @@ static void format_config_release(struct format_config *cfg)
 	string_list_clear(&cfg->extra_cc, 0);
 	strbuf_release(&cfg->sprefix);
 	free(cfg->fmt_patch_suffix);
+	free(cfg->fmt_cover_letter_commit_list);
 }
 
 static enum cover_from_description parse_cover_from_description(const char *arg)
@@ -1052,6 +1054,19 @@ static int git_format_config(const char *var, const char *value,
 		cfg->config_cover_letter = git_config_bool(var, value) ? COVER_ON : COVER_OFF;
 		return 0;
 	}
+	if (!strcmp(var, "format.commitlistformat")) {
+		struct strbuf tmp = STRBUF_INIT;
+		strbuf_init(&tmp, 0);
+		strbuf_addstr(&tmp, "log:");
+		if (value)
+			strbuf_addstr(&tmp, value);
+		else
+			strbuf_addstr(&tmp, "%s");
+
+		git_config_string(&cfg->fmt_cover_letter_commit_list, var, tmp.buf);
+		strbuf_release(&tmp);
+		return 0;
+	}
 	if (!strcmp(var, "format.outputdirectory")) {
 		FREE_AND_NULL(cfg->config_output_directory);
 		return git_config_string(&cfg->config_output_directory, var, value);
@@ -2321,6 +2336,13 @@ int cmd_format_patch(int argc,
 		goto done;
 	total = list.nr;
 
+	if (cover_letter_fmt && (strcmp(cover_letter_fmt, "shortlog") && strncmp(cover_letter_fmt, "log:", 4))) {
+		die(_("--cover-letter: invalid format spec"));
+	}
+
+	if (!cover_letter_fmt)
+		cover_letter_fmt = cfg.fmt_cover_letter_commit_list;
+
 	if (cover_letter == -1) {
 		if (cfg.config_cover_letter == COVER_AUTO)
 			cover_letter = total > 1;
-- 
2.53.0.4.geaa3cc5f7e