[PATCH 4/8] [GSOC] ref-filter: add %(rest) atom

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

From: ZheNing Hu <adlternative@gmail.com>

In order to let "cat-file --batch=%(rest)" use the ref-filter
interface, add %(rest) atom for ref-filter. "git for-each-ref",
"git branch", "git tag" and "git verify-tag" will reject %(rest)
by default.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Hariom Verma <hariom18599@gmail.com>
Signed-off-by: ZheNing Hu <adlternative@gmail.com>
---
 ref-filter.c             | 21 +++++++++++++++++++++
 ref-filter.h             |  5 ++++-
 t/t3203-branch-output.sh |  4 ++++
 t/t6300-for-each-ref.sh  |  4 ++++
 t/t7004-tag.sh           |  4 ++++
 t/t7030-verify-tag.sh    |  4 ++++
 6 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/ref-filter.c b/ref-filter.c
index af8c15aef44d..8868cf98f090 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -157,6 +157,7 @@ enum atom_type {
 	ATOM_IF,
 	ATOM_THEN,
 	ATOM_ELSE,
+	ATOM_REST,
 };
 
 /*
@@ -559,6 +560,15 @@ static int if_atom_parser(struct ref_format *format, struct used_atom *atom,
 	return 0;
 }
 
+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"));
+	format->use_rest = 1;
+	return 0;
+}
+
 static int head_atom_parser(struct ref_format *format, struct used_atom *atom,
 			    const char *arg, struct strbuf *unused_err)
 {
@@ -615,6 +625,7 @@ static struct {
 	[ATOM_IF] = { "if", SOURCE_NONE, FIELD_STR, if_atom_parser },
 	[ATOM_THEN] = { "then", SOURCE_NONE },
 	[ATOM_ELSE] = { "else", SOURCE_NONE },
+	[ATOM_REST] = { "rest", SOURCE_NONE, FIELD_STR, rest_atom_parser },
 	/*
 	 * Please update $__git_ref_fieldlist in git-completion.bash
 	 * when you add new atoms
@@ -1006,6 +1017,9 @@ int verify_ref_format(struct ref_format *format)
 		at = parse_ref_filter_atom(format, sp + 2, ep, &err);
 		if (at < 0)
 			die("%s", err.buf);
+		if (used_atom[at].atom_type == ATOM_REST)
+			die("this command reject atom %%(%.*s)", (int)(ep - sp - 2), sp + 2);
+
 		if (format->quote_style && used_atom[at].atom_type == ATOM_RAW &&
 		    used_atom[at].u.raw_data.option == RAW_BARE)
 			die(_("--format=%.*s cannot be used with"
@@ -1920,6 +1934,12 @@ static int populate_value(struct ref_array_item *ref, struct strbuf *err)
 			v->handler = else_atom_handler;
 			v->s = xstrdup("");
 			continue;
+		} else if (atom_type == ATOM_REST) {
+			if (ref->rest)
+				v->s = xstrdup(ref->rest);
+			else
+				v->s = xstrdup("");
+			continue;
 		} else
 			continue;
 
@@ -2137,6 +2157,7 @@ static struct ref_array_item *new_ref_array_item(const char *refname,
 
 	FLEX_ALLOC_STR(ref, refname, refname);
 	oidcpy(&ref->objectname, oid);
+	ref->rest = NULL;
 
 	return ref;
 }
diff --git a/ref-filter.h b/ref-filter.h
index 74fb423fc89f..9dc07476a584 100644
--- a/ref-filter.h
+++ b/ref-filter.h
@@ -38,6 +38,7 @@ struct ref_sorting {
 
 struct ref_array_item {
 	struct object_id objectname;
+	const char *rest;
 	int flag;
 	unsigned int kind;
 	const char *symref;
@@ -76,14 +77,16 @@ struct ref_format {
 	 * verify_ref_format() afterwards to finalize.
 	 */
 	const char *format;
+	const char *rest;
 	int quote_style;
+	int use_rest;
 	int use_color;
 
 	/* Internal state to ref-filter */
 	int need_color_reset_at_eol;
 };
 
-#define REF_FORMAT_INIT { NULL, 0, -1 }
+#define REF_FORMAT_INIT { NULL, NULL, 0, 0, -1 }
 
 /*  Macros for checking --merged and --no-merged options */
 #define _OPT_MERGED_NO_MERGED(option, filter, h) \
diff --git a/t/t3203-branch-output.sh b/t/t3203-branch-output.sh
index 5325b9f67a00..2780ec8803fd 100755
--- a/t/t3203-branch-output.sh
+++ b/t/t3203-branch-output.sh
@@ -340,6 +340,10 @@ test_expect_success 'git branch --format option' '
 	test_cmp expect actual
 '
 
+test_expect_success 'git branch with --format=%(rest) must failed' '
+	test_must_fail git branch --format="%(rest)" >actual
+'
+
 test_expect_success 'worktree colors correct' '
 	cat >expect <<-EOF &&
 	* <GREEN>(HEAD detached from fromtag)<RESET>
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index e2867de791e7..8c97c3b877c6 100755
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -1187,6 +1187,10 @@ test_expect_success 'basic atom: head contents:trailers' '
 	test_cmp expect actual.clean
 '
 
+test_expect_success 'basic atom: rest must failed' '
+	test_must_fail git for-each-ref --format="%(rest)" refs/heads/main
+'
+
 test_expect_success 'trailer parsing not fooled by --- line' '
 	git commit --allow-empty -F - <<-\EOF &&
 	this is the subject
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index 2f72c5c6883e..9fc4c4323949 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -1998,6 +1998,10 @@ test_expect_success '--format should list tags as per format given' '
 	test_cmp expect actual
 '
 
+test_expect_success 'git tag -l with --format="%(rest)" must failed' '
+	test_must_fail git tag -l --format="%(rest)" "v1*"
+'
+
 test_expect_success "set up color tests" '
 	echo "<RED>v1.0<RESET>" >expect.color &&
 	echo "v1.0" >expect.bare &&
diff --git a/t/t7030-verify-tag.sh b/t/t7030-verify-tag.sh
index 3cefde9602bf..785b32eb88f9 100755
--- a/t/t7030-verify-tag.sh
+++ b/t/t7030-verify-tag.sh
@@ -194,6 +194,10 @@ test_expect_success GPG 'verifying tag with --format' '
 	test_cmp expect actual
 '
 
+test_expect_success GPG 'verifying tag with --format="%(rest)" must failed' '
+	test_must_fail git verify-tag --format="%(rest)" "fourth-signed"
+'
+
 test_expect_success GPG 'verifying a forged tag with --format should fail silently' '
 	test_must_fail git verify-tag --format="tagname : %(tag)" $(cat forged1.tag) >actual-forged &&
 	test_must_be_empty actual-forged
-- 
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