[PATCH v3 07/12] hook: allow event = "" to overwrite previous values

From

Adrian Ratiu <adrian.ratiu@collabora.com>

Date

Mar 1, 2026, 18:44 UTC

Message-ID

<20260301184500.1488433-8-adrian.ratiu@collabora.com>

In-Reply-To

<20260301184500.1488433-1-adrian.ratiu@collabora.com>

Suggested-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
---
 Documentation/config/hook.adoc |  4 +++-
 hook.c                         | 31 ++++++++++++++++++++-----------
 t/t1800-hook.sh                | 12 ++++++++++++
 3 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/Documentation/config/hook.adoc b/Documentation/config/hook.adoc
index 4bbda5636d..d0023b2deb 100644
--- a/Documentation/config/hook.adoc
+++ b/Documentation/config/hook.adoc
@@ -12,7 +12,9 @@ hook.<friendly-name>.event::
 	linkgit:githooks[5] for a complete list of hook events.) On the
 	specified event, the associated `hook.<friendly-name>.command` is executed.
 	This is a multi-valued key. To run `hook.<friendly-name>` on multiple
-	events, specify the key more than once. See linkgit:git-hook[1].
+	events, specify the key more than once. An empty value resets
+	the list of events, clearing any previously defined events for
+	`hook.<friendly-name>`. See linkgit:git-hook[1].
 
 hook.<friendly-name>.enabled::
 	Whether the hook `hook.<friendly-name>` is enabled. Defaults to `true`.
diff --git a/hook.c b/hook.c
index 24eb330cac..696919e703 100644
--- a/hook.c
+++ b/hook.c
@@ -133,18 +133,27 @@ static int hook_config_lookup_all(const char *key, const char *value,
 	hook_name = xmemdupz(name, name_len);
 
 	if (!strcmp(subkey, "event")) {
-		struct string_list *hooks =
-			strmap_get(&data->event_hooks, value);
+		if (!*value) {
+			/* Empty values reset previous events for this hook. */
+			struct hashmap_iter iter;
+			struct strmap_entry *e;
+
+			strmap_for_each_entry(&data->event_hooks, &iter, e)
+				unsorted_string_list_remove(e->value, hook_name, 0);
+		} else {
+			struct string_list *hooks =
+				strmap_get(&data->event_hooks, value);
+
+			if (!hooks) {
+				CALLOC_ARRAY(hooks, 1);
+				string_list_init_dup(hooks);
+				strmap_put(&data->event_hooks, value, hooks);
+			}
 
-		if (!hooks) {
-			hooks = xcalloc(1, sizeof(*hooks));
-			string_list_init_dup(hooks);
-			strmap_put(&data->event_hooks, value, hooks);
+			/* Re-insert if necessary to preserve last-seen order. */
+			unsorted_string_list_remove(hooks, hook_name, 0);
+			string_list_append(hooks, hook_name);
 		}
-
-		/* Re-insert if necessary to preserve last-seen order. */
-		unsorted_string_list_remove(hooks, hook_name, 0);
-		string_list_append(hooks, hook_name);
 	} else if (!strcmp(subkey, "command")) {
 		/* Store command overwriting the old value */
 		char *old = strmap_put(&data->commands, hook_name,
@@ -160,7 +169,7 @@ static int hook_config_lookup_all(const char *key, const char *value,
 			break;
 		case 1: /* enabled: undo a prior disabled entry */
 			unsorted_string_list_remove(&data->disabled_hooks,
-						    hook_name);
+						    hook_name, 0);
 			break;
 		default:
 			break; /* ignore unrecognised values */
diff --git a/t/t1800-hook.sh b/t/t1800-hook.sh
index fb8cfc8137..c14ec661b9 100755
--- a/t/t1800-hook.sh
+++ b/t/t1800-hook.sh
@@ -225,6 +225,18 @@ test_expect_success 'git hook list reorders on duplicate event declarations' '
 	test_cmp expected actual
 '
 
+test_expect_success 'git hook list: empty event value resets events' '
+	setup_hooks &&
+
+	# ghi is configured for pre-commit; reset it with an empty value
+	test_config hook.ghi.event "" --add &&
+
+	# only def should remain for pre-commit
+	echo "def" >expected &&
+	git hook list pre-commit >actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'hook can be configured for multiple events' '
 	setup_hooks &&
 

-- 
2.52.0.732.gb351b5166d.dirty