[PATCH 2/5] ref-filter: factor out "%(foo) does not take arguments" errors

[Jeff King <peff@peff.net>]

Many atom parsers give the same error message, differing only in the
name of the atom. If we use "%s does not take arguments", that should
make life easier for translators, as they only need to translate one
string. And in doing so, we can easily pull it into a helper function to
make sure they are all using the exact same string.

I've added a basic test here for %(HEAD), just to make sure this code is
exercised at all in the test suite. We could cover each such atom, but
the effort-to-reward ratio of trying to maintain an exhaustive list
doesn't seem worth it.

Signed-off-by: Jeff King <peff@peff.net>
---
 ref-filter.c            | 16 +++++++++++-----
 t/t6300-for-each-ref.sh |  6 ++++++
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/ref-filter.c b/ref-filter.c
index 08ac5f886e..639b18ab36 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -228,6 +228,12 @@ static int strbuf_addf_ret(struct strbuf *sb, int ret, const char *fmt, ...)
 	return ret;
 }
 
+static int err_no_arg(struct strbuf *sb, const char *name)
+{
+	strbuf_addf(sb, _("%%(%s) does not take arguments"), name);
+	return -1;
+}
+
 static int color_atom_parser(struct ref_format *format, struct used_atom *atom,
 			     const char *color_value, struct strbuf *err)
 {
@@ -317,7 +323,7 @@ static int objecttype_atom_parser(struct ref_format *format, struct used_atom *a
 				  const char *arg, struct strbuf *err)
 {
 	if (arg)
-		return strbuf_addf_ret(err, -1, _("%%(objecttype) does not take arguments"));
+		return err_no_arg(err, "objecttype");
 	if (*atom->name == '*')
 		oi_deref.info.typep = &oi_deref.type;
 	else
@@ -349,7 +355,7 @@ static int deltabase_atom_parser(struct ref_format *format, struct used_atom *at
 				 const char *arg, struct strbuf *err)
 {
 	if (arg)
-		return strbuf_addf_ret(err, -1, _("%%(deltabase) does not take arguments"));
+		return err_no_arg(err, "deltabase");
 	if (*atom->name == '*')
 		oi_deref.info.delta_base_oid = &oi_deref.delta_base_oid;
 	else
@@ -361,7 +367,7 @@ static int body_atom_parser(struct ref_format *format, struct used_atom *atom,
 			    const char *arg, struct strbuf *err)
 {
 	if (arg)
-		return strbuf_addf_ret(err, -1, _("%%(body) does not take arguments"));
+		return err_no_arg(err, "body");
 	atom->u.contents.option = C_BODY_DEP;
 	return 0;
 }
@@ -565,7 +571,7 @@ static int rest_atom_parser(struct ref_format *format, struct used_atom *atom,
 			    const char *arg, struct strbuf *err)
 {
 	if (arg)
-		return strbuf_addf_ret(err, -1, _("%%(rest) does not take arguments"));
+		return err_no_arg(err, "rest");
 	format->use_rest = 1;
 	return 0;
 }
@@ -574,7 +580,7 @@ static int head_atom_parser(struct ref_format *format, struct used_atom *atom,
 			    const char *arg, struct strbuf *err)
 {
 	if (arg)
-		return strbuf_addf_ret(err, -1, _("%%(HEAD) does not take arguments"));
+		return err_no_arg(err, "HEAD");
 	atom->u.head = resolve_refdup("HEAD", RESOLVE_REF_READING, NULL, NULL);
 	return 0;
 }
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index fa38b87441..8d99658ef8 100755
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -1242,6 +1242,12 @@ test_expect_success 'basic atom: rest must fail' '
 	test_must_fail git for-each-ref --format="%(rest)" refs/heads/main
 '
 
+test_expect_success 'HEAD atom does not take arguments' '
+	test_must_fail git for-each-ref --format="%(HEAD:foo)" 2>err &&
+	echo "fatal: %(HEAD) does not take arguments" >expect &&
+	test_cmp expect err
+'
+
 test_expect_success 'trailer parsing not fooled by --- line' '
 	git commit --allow-empty -F - <<-\EOF &&
 	this is the subject
-- 
2.39.0.550.g5015380a67