From f161547b40c048bc891bb6b9addc6f301533ab1d Mon Sep 17 00:00:00 2001
From: Thanasis Daglis <ath.daglis@gmail.com>
Date: Fri, 2 Oct 2026 19:50:38 +0300
Subject: [PATCH] fix(vidstack): correct slider video preview error handling

---
 .../ui/sliders/slider-video.test.ts           | 128 ++++++++++++++++++
 .../src/components/ui/sliders/slider-video.ts |   4 +-
 2 files changed, 131 insertions(+), 1 deletion(-)
 create mode 100644 packages/vidstack/src/components/ui/sliders/slider-video.test.ts

diff --git a/packages/vidstack/src/components/ui/sliders/slider-video.test.ts b/packages/vidstack/src/components/ui/sliders/slider-video.test.ts
new file mode 100644
index 000000000..ea6fa5d11
--- /dev/null
+++ b/packages/vidstack/src/components/ui/sliders/slider-video.test.ts
@@ -0,0 +1,128 @@
+import { createComponent, provideContext, root, tick } from 'maverick.js';
+import type { DOMEvent } from 'maverick.js/std';
+import { vi } from 'vitest';
+
+import { mediaContext } from '../../../core/api/media-context';
+import { mediaState } from '../../../core/api/player-state';
+import { SliderVideo } from './slider-video';
+import { Slider } from './slider/slider';
+
+function setupSliderVideo(sameHost = true) {
+  let dispose!: () => void;
+  const $state = mediaState.create(),
+    $slider = Slider.state.create(),
+    video = document.createElement('video'),
+    host = sameHost ? video : document.createElement('div'),
+    errors: DOMEvent[] = [];
+
+  $state.canLoad.set(true);
+  $state.providedDuration.set(120);
+  if (!sameHost) host.append(video);
+
+  // Bound the pre-fix recursion so the regression fails without overflowing the test runner.
+  host.addEventListener(
+    'error',
+    (event) => {
+      if ('trigger' in event) {
+        errors.push(event as DOMEvent);
+        if (errors.length > 1) event.stopImmediatePropagation();
+      }
+    },
+    { capture: true },
+  );
+
+  const preview = root((stop) => {
+    dispose = stop;
+    provideContext(mediaContext, { $state } as any);
+    provideContext(Slider.state, $slider);
+    const instance = createComponent(SliderVideo, {
+      props: { src: '/preview.mp4' },
+    }) as any;
+    // Vitest resolves Maverick's node export, where dispatch is a no-op.
+    // Reproduce its browser dispatch on the actual host (a video in React).
+    vi.spyOn(instance, 'dispatch').mockImplementation((type, init) => {
+      const event = new Event(type as string);
+      Object.defineProperties(event, {
+        target: { get: () => instance },
+        trigger: { value: (init as { trigger?: Event })?.trigger },
+      });
+      return host.dispatchEvent(event);
+    });
+    instance.$$.setup();
+    instance.$state.video.set(video);
+    instance.$$.attach(host);
+    instance.$$.connect();
+    return instance;
+  }) as any;
+  tick();
+  return { preview, host, video, errors, $slider, dispose };
+}
+
+describe(SliderVideo.name, function () {
+  it('does not mark a valid, loaded preview as errored or hidden', function () {
+    const { video, preview, dispose } = setupSliderVideo();
+    try {
+      video.dispatchEvent(new Event('canplay'));
+      tick();
+      expect(preview.$state.canPlay()).to.be.true;
+      expect(preview.$state.hidden()).to.be.false;
+      expect(preview.$$.attrs['data-error']()).to.be.false;
+      expect(preview.$$.attrs['data-loading']()).to.be.false;
+    } finally {
+      dispose();
+    }
+  });
+
+  for (const sameHost of [true, false]) {
+    it(`dispatches one error when video ${sameHost ? 'is' : 'is inside'} the host`, function () {
+      const { video, preview, errors, dispose } = setupSliderVideo(sameHost);
+      try {
+        const error = new Event('error');
+        video.dispatchEvent(error);
+        tick();
+        expect(errors).to.have.length(1);
+        expect(errors[0].trigger).to.equal(error);
+        expect(preview.$state.error()).to.equal(error);
+        expect(preview.$state.canPlay()).to.be.false;
+        expect(preview.$$.attrs['data-error']()).to.be.true;
+        expect(preview.$state.hidden()).to.be.true;
+      } finally {
+        dispose();
+      }
+    });
+  }
+
+  it('clears an error and restores the preview after the source changes', function () {
+    const { video, preview, dispose } = setupSliderVideo(false);
+    try {
+      video.dispatchEvent(new Event('error'));
+      tick();
+      preview.$props.src.set('/replacement.mp4');
+      tick();
+      expect(preview.$state.error()).to.equal(null);
+      expect(preview.$$.attrs['data-error']()).to.be.false;
+      expect(preview.$state.hidden()).to.be.false;
+      expect(preview.$$.attrs['data-loading']()).to.be.true;
+      video.dispatchEvent(new Event('canplay'));
+      tick();
+      expect(preview.$$.attrs['data-loading']()).to.be.false;
+    } finally {
+      dispose();
+    }
+  });
+
+  it('keeps seeking the preview to the slider pointer position', function () {
+    const { video, $slider, dispose } = setupSliderVideo();
+    try {
+      $slider.pointerValue.set(25);
+      video.dispatchEvent(new Event('canplay'));
+      tick();
+      expect(video.currentTime).to.equal(30);
+      $slider.pointerValue.set(75);
+      tick();
+      expect(video.currentTime).to.equal(90);
+    } finally {
+      dispose();
+    }
+  });
+});
diff --git a/packages/vidstack/src/components/ui/sliders/slider-video.ts b/packages/vidstack/src/components/ui/sliders/slider-video.ts
index 58bca0c7e..6259f9792 100644
--- a/packages/vidstack/src/components/ui/sliders/slider-video.ts
+++ b/packages/vidstack/src/components/ui/sliders/slider-video.ts
@@ -96,7 +96,7 @@ export class SliderVideo extends Component<SliderVideoProps, SliderVideoState, S
 
   #hasError() {
     const { error } = this.$state;
-    return !isNull(error);
+    return !isNull(error());
   }
 
   #watchHidden() {
@@ -120,6 +120,8 @@ export class SliderVideo extends Component<SliderVideoProps, SliderVideoState, S
   }
 
   #onError(event: ErrorEvent) {
+    if (event.target === this) return;
+
     const { canPlay, error } = this.$state;
     canPlay.set(false);
     error.set(event);