fix(core): correct Delizia loader completion detection

[romanz]

This issue was found while debugging a flaky click test on T3T1 emulator:
tests/click_tests/test_lock.py::test_hold_to_lock

Sample failures:
https://github.com/trezor/trezor-firmware/actions/runs/13209659963/job/36880750418
https://github.com/trezor/trezor-firmware/actions/runs/13189762414/job/36820368643
https://github.com/trezor/trezor-firmware/actions/runs/13146713535/job/36686537519
https://github.com/trezor/trezor-firmware/actions/runs/13124809110/job/36619045092
https://github.com/trezor/trezor-firmware/actions/runs/13103415015/job/36554567296
https://github.com/trezor/trezor-firmware/actions/runs/13093382180/job/36532710349

With the following logging added [1], the test failure seems to happen when the loader detects that it is ShrunkCompletely (probably due to animation events timing jitter) and stops the animation:

[1] Debug patch

diff --git a/core/embed/rust/src/ui/component/base.rs b/core/embed/rust/src/ui/component/base.rs
index 9b24c44fd..efe88e78b 100644
--- a/core/embed/rust/src/ui/component/base.rs
+++ b/core/embed/rust/src/ui/component/base.rs
@@ -575,6 +575,7 @@ impl EventCtx {
     }
 
     fn register_timer(&mut self, token: TimerToken, duration: Duration) {
+        dbg_println!("register_timer: {:?} {}ms", token, duration.to_millis());
         if self.timers.push((token, duration)).is_err() {
             // The timer queue is full, this would be a development error in the layout
             // layer. Let's panic in the debug env.
diff --git a/core/embed/rust/src/ui/layout/obj.rs b/core/embed/rust/src/ui/layout/obj.rs
index 4ec68214a..f546e9fce 100644
--- a/core/embed/rust/src/ui/layout/obj.rs
+++ b/core/embed/rust/src/ui/layout/obj.rs
@@ -285,6 +285,7 @@ impl LayoutObjInner {
 
         // Drain any pending timers into the callback.
         while let Some((token, duration)) = self.event_ctx.pop_timer() {
+            dbg_println!("timer_fn: {:?} {}ms", token, duration.to_millis());
             let token = token.try_into();
             let duration = duration.try_into();
             if let (Ok(token), Ok(duration)) = (token, duration) {
diff --git a/core/embed/rust/src/ui/layout_delizia/component/homescreen.rs b/core/embed/rust/src/ui/layout_delizia/component/homescreen.rs
index fe68b28a5..e80452b19 100644
--- a/core/embed/rust/src/ui/layout_delizia/component/homescreen.rs
+++ b/core/embed/rust/src/ui/layout_delizia/component/homescreen.rs
@@ -507,6 +507,7 @@ impl Homescreen {
     }
 
     fn event_hold(&mut self, ctx: &mut EventCtx, event: Event) -> bool {
+        dbg_println!("event_hold: {:?} animating={}", event, self.loader.is_animating());
         match event {
             Event::Touch(TouchEvent::TouchStart(_)) => {
                 if self.loader.is_animating() {
diff --git a/core/embed/rust/src/ui/layout_delizia/component/loader.rs b/core/embed/rust/src/ui/layout_delizia/component/loader.rs
index 158a0bc83..a67a160ce 100644
--- a/core/embed/rust/src/ui/layout_delizia/component/loader.rs
+++ b/core/embed/rust/src/ui/layout_delizia/component/loader.rs
@@ -180,15 +180,19 @@ impl Component for Loader {
                 if self.is_completely_grown(now) {
                     #[cfg(feature = "haptic")]
                     play(HapticEffect::HoldToConfirm);
+                    dbg_println!("Loader::event {:?} -> GrownCompletely", event);
                     return Some(LoaderMsg::GrownCompletely);
                 } else if self.is_completely_shrunk(now) {
+                    dbg_println!("Loader::event {:?} -> ShrunkCompletely", event);
                     return Some(LoaderMsg::ShrunkCompletely);
                 } else {
                     // There is further progress in the animation, request an animation frame event.
                     ctx.request_anim_frame();
+                    return None;
                 }
             }
         }
+        dbg_println!("Loader::event {:?} -> None", event);
         None
     }
 
diff --git a/tests/click_tests/test_lock.py b/tests/click_tests/test_lock.py
index 9a0340910..0f270d343 100644
--- a/tests/click_tests/test_lock.py
+++ b/tests/click_tests/test_lock.py
@@ -14,6 +14,7 @@
 # You should have received a copy of the License along with this library.
 # If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
 
+import logging
 import time
 from typing import TYPE_CHECKING
 
@@ -28,6 +29,7 @@ if TYPE_CHECKING:
     from ..device_handler import BackgroundDeviceHandler
 
 
+LOG = logging.getLogger()
 PIN4 = "1234"
 
 
@@ -77,17 +79,20 @@ def test_hold_to_lock(device_handler: "BackgroundDeviceHandler"):
     hold(lock_duration)
     assert device_handler.features().unlocked is False
 
-    # unlock by touching
-    if debug.layout_type is LayoutType.Caesar:
-        debug.press_right()
-    else:
-        debug.click(buttons.INFO)
-    layout = debug.read_layout()
-    assert "PinKeyboard" in layout.all_components()
-    debug.input("1234")
-
-    assert device_handler.features().unlocked is True
-
-    # lock
-    hold(lock_duration)
-    assert device_handler.features().unlocked is False
+    for i in range(1000):
+        # unlock by touching
+        if debug.layout_type is LayoutType.Caesar:
+            debug.press_right()
+        else:
+            debug.click(buttons.INFO)
+        layout = debug.read_layout()
+        assert "PinKeyboard" in layout.all_components()
+        debug.input("1234")
+
+        assert device_handler.features().unlocked is True
+
+        # lock
+        LOG.info("LOCK: #%d", i)
+        hold(lock_duration)
+        LOG.info("STAT: #%d", i)
+        assert device_handler.features().unlocked is False

[github-actions]

core UI changes	device test	click test	persistence test
T2T1 Model T	test(screens) main(screens)	test(screens) main(screens)	test(screens) main(screens)
T3B1 Safe 3	test(screens) main(screens)	test(screens) main(screens)	test(screens) main(screens)
T3T1 Safe 5	test(screens) main(screens)	test(screens) main(screens)	test(screens) main(screens)
All	main(screens)

[romanz]

Tested locally on T3T1 emulator:

core/emu.py -o debug.log -sea -c pytest tests/click_tests -k test_hold_to_lock -vx --color=yes --count 100 2>&1 | stamp
2025-02-10 12:57:25.684756 TREZOR_PATH=udp:127.0.0.1:21324
2025-02-10 12:57:25.684842 TREZOR_PROFILE_DIR=/var/tmp
2025-02-10 12:57:25.684857 TREZOR_UDP_PORT=21324
2025-02-10 12:57:25.684867 TREZOR_FIDO2_UDP_PORT=21326
2025-02-10 12:57:25.684877 TREZOR_SRC=/home/rzeyde/src/trezor-firmware/core/src
2025-02-10 12:57:25.686108 Waiting for emulator to come up...
2025-02-10 12:57:25.887237 Emulator ready after 0.201 seconds
2025-02-10 12:57:26.240309 ============================= test session starts ==============================
2025-02-10 12:57:26.240364 platform linux -- Python 3.10.10, pytest-8.3.2, pluggy-1.5.0 -- /home/rzeyde/src/trezor-firmware/.venv/bin/python
2025-02-10 12:57:26.240375 cachedir: .pytest_cache
2025-02-10 12:57:26.240385 hypothesis profile 'default' -> database=DirectoryBasedExampleDatabase('/home/rzeyde/src/trezor-firmware/.hypothesis/examples')
2025-02-10 12:57:26.240394 Using --random-order-bucket=module
2025-02-10 12:57:26.240403 Using --random-order-seed=877340
2025-02-10 12:57:26.240412 
2025-02-10 12:57:26.240421 rootdir: /home/rzeyde/src/trezor-firmware
2025-02-10 12:57:26.240430 configfile: setup.cfg
2025-02-10 12:57:26.240440 plugins: xdist-2.5.0, flaky-3.8.1, forked-1.4.0, hypothesis-6.36.1, ordering-0.6, repeat-0.9.3, timeout-2.1.0, random-order-1.0.4
2025-02-10 12:57:26.791454 collecting ... collected 8100 items / 8000 deselected / 100 selected
2025-02-10 13:13:05.558367 
2025-02-10 13:13:05.558379 =============== 100 passed, 8000 deselected in 939.36s (0:15:39) ===============
2025-02-10 13:13:05.807124 Terminating emulator...
2025-02-10 13:13:05.814661 Emulator shut down after 0.007 seconds

[romanz]

Should I also fix similar Loader implementation for Bolt and Caesar layouts?

core/embed/rust/src/ui/layout_bolt/component/loader.rs
141:    pub fn is_completely_grown(&self, now: Instant) -> bool {
145:    pub fn is_completely_shrunk(&self, now: Instant) -> bool {

core/embed/rust/src/ui/layout_caesar/component/loader.rs
156:    pub fn is_completely_grown(&self, now: Instant) -> bool {
160:    pub fn is_completely_shrunk(&self, now: Instant) -> bool {

core/embed/rust/src/ui/layout_delizia/component/loader.rs
145:    pub fn is_completely_grown(&self, now: Instant) -> bool {
149:    pub fn is_completely_shrunk(&self, now: Instant) -> bool {