fix(behaviors): Fix bug in nested sticky keys

If multiple sticky keys with quick release were nested, only the first one
was properly released. This fix makes sure all of them are released properly.

Fixes https://github.com/zmkfirmware/zmk/issues/1149

app/src/behaviors/behavior_sticky_key.c

@@ -188,6 +188,9 @@ static int sticky_key_keycode_state_changed_listener(const zmk_event_t *eh) {
     if (ev == NULL) {
         return ZMK_EV_EVENT_BUBBLE;
     }
+
+    // keep track whether the event has been reraised, so we only reraise it once
+    bool event_reraised = false;
     for (int i = 0; i < ZMK_BHV_STICKY_KEY_MAX_HELD; i++) {
         struct active_sticky_key *sticky_key = &active_sticky_keys[i];
         if (sticky_key->position == ZMK_BHV_STICKY_KEY_POSITION_FREE) {
@@ -223,10 +226,12 @@ static int sticky_key_keycode_state_changed_listener(const zmk_event_t *eh) {
             if (sticky_key->timer_started) {
                 stop_timer(sticky_key);
                 if (sticky_key->config->quick_release) {
-                    // continue processing the event. Release the sticky key afterwards.
-                    ZMK_EVENT_RAISE_AFTER(eh, behavior_sticky_key);
+                    // immediately release the sticky key after the key press is handled.
+                    if (!event_reraised) {
+                        ZMK_EVENT_RAISE_AFTER(eh, behavior_sticky_key);
+                        event_reraised = true;
+                    }
                     release_sticky_key_behavior(sticky_key, ev->timestamp);
-                    return ZMK_EV_EVENT_CAPTURED;
                 }
             }
             sticky_key->modified_key_usage_page = ev->usage_page;
@@ -240,6 +245,9 @@ static int sticky_key_keycode_state_changed_listener(const zmk_event_t *eh) {
             }
         }
     }
+    if (event_reraised) {
+        return ZMK_EV_EVENT_CAPTURED;
+    }
     return ZMK_EV_EVENT_BUBBLE;
 }
 

app/tests/sticky-keys/10-sl-sl-kp/events.patterns

@@ -0,0 +1 @@
+s/.*hid_listener_keycode_//p

app/tests/sticky-keys/10-sl-sl-kp/keycode_events.snapshot

@@ -0,0 +1,8 @@
+pressed: usage_page 0x07 keycode 0x1e implicit_mods 0x00 explicit_mods 0x00
+released: usage_page 0x07 keycode 0x1e implicit_mods 0x00 explicit_mods 0x00
+pressed: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00
+released: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00
+pressed: usage_page 0x07 keycode 0x1e implicit_mods 0x00 explicit_mods 0x00
+released: usage_page 0x07 keycode 0x1e implicit_mods 0x00 explicit_mods 0x00
+pressed: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00
+released: usage_page 0x07 keycode 0x04 implicit_mods 0x00 explicit_mods 0x00

app/tests/sticky-keys/10-sl-sl-kp/native_posix.keymap

@@ -0,0 +1,65 @@
+#include <dt-bindings/zmk/keys.h>
+#include <behaviors.dtsi>
+#include <dt-bindings/zmk/kscan-mock.h>
+
+/*
+ sticky layers should quick-release.
+ Thus, the second keypress should be on the default layer, not on the lower_layer.
+*/
+
+/ {
+	keymap {
+		compatible = "zmk,keymap";
+		label ="Default keymap";
+
+		default_layer {
+			bindings = <
+				&sl 1 &kp A
+				&none &none>;
+		};
+
+		layer_1 {
+			bindings = <
+				&sl 2 &none
+				&none &none>;
+		};
+
+		layer_2 {
+			bindings = <
+				&none &kp NUM_1
+				&none &none>;
+		};
+	};
+};
+
+&kscan {
+	events = <
+		/* press sl 1 */
+		ZMK_MOCK_PRESS(0,0,10) 
+		ZMK_MOCK_RELEASE(0,0,10) 
+		/* press sl 2 */
+		ZMK_MOCK_PRESS(0,0,10) 
+		ZMK_MOCK_RELEASE(0,0,10) 
+		/* press 1 */
+		ZMK_MOCK_PRESS(0,1,10)
+		ZMK_MOCK_RELEASE(0,1,10)
+		/* press A */
+		ZMK_MOCK_PRESS(0,1,10)
+		ZMK_MOCK_RELEASE(0,1,10)
+
+		/* repeat test to check if cleanup is done correctly */
+		/* press sl 1 */
+		ZMK_MOCK_PRESS(0,0,10) 
+		ZMK_MOCK_RELEASE(0,0,10) 
+		/* press sl 2 */
+		ZMK_MOCK_PRESS(0,0,10) 
+		ZMK_MOCK_RELEASE(0,0,10) 
+		/* press 1 */
+		ZMK_MOCK_PRESS(0,1,10)
+		ZMK_MOCK_RELEASE(0,1,10)
+		/* press A */
+		ZMK_MOCK_PRESS(0,1,10)
+		ZMK_MOCK_RELEASE(0,1,10)
+
+	>;
+};