test(auto-thumbnail): [PKG-AUTO-THUMB-02] reproduce extraction and lifecycle failures

package.json

@@ -51,7 +51,7 @@
     "ci:build": "yarn build:types && yarn build all && yarn build:i18n && yarn build:ts && yarn build:docs && yarn test:imports",
     "test:imports": "node --test test/esm.test.js test/i18n.test.js test/ssr.test.js",
     "typecheck": "node scripts/typecheck.mjs",
-    "test:unit": "node --test test/thumbnail-emitter.test.js test/thumbnail-runtime.test.js test/thumbnail-vendor.test.js test/thumbnail-lifecycle.test.js test/thumbnail-input.test.js test/thumbnail.test.js test/iframe-navigation.test.js test/iframe-boundaries.test.js test/iframe-lifecycle.test.js test/iframe.test.js test/mediabunny.test.js test/mediabunny-shim.test.js test/mediabunny-coordination.test.js test/mediabunny-video.test.js test/mediabunny-audio.test.js test/mediabunny-hls.test.js test/mediabunny-entry.test.js test/mediabunny-capability.test.js test/mediabunny-load.test.js test/mediabunny-input.test.js test/dpip.test.js test/dpip-lifecycle.test.js test/canvas.test.js test/canvas-lifecycle.test.js test/ambilight.test.js test/ambilight-lifecycle.test.js test/ambilight-proxy.test.js test/vast.test.js test/vast-lifecycle.test.js test/ads.test.js test/ads-lifecycle.test.js test/playback.test.js test/dash-control.test.js test/dash-contract.test.js test/dash-lifecycle.test.js test/dash-events.test.js test/hls-control.test.js test/audio-track.test.js test/public-behavior.test.js test/helpers.test.js test/chapter.test.js test/utils.test.js test/resource-scope.test.js test/instance-lifecycle.test.js test/options.test.js test/media-hosts.test.js test/plugins.test.js test/source.test.js test/playback-properties.test.js test/media-events.test.js test/template-resources.test.js test/core-vendor.test.js test/component-resources.test.js test/setting-model.test.js test/setting-layout.test.js test/setting-resources.test.js test/subtitle.test.js test/display-native.test.js test/display-video-fullscreen.test.js test/display-pip.test.js test/display-mini.test.js test/display-sizing.test.js test/display-orientation.test.js test/hotkey.test.js test/listener-registry.test.js test/global-events.test.js test/pointer-events.test.js test/gesture.test.js test/event-scheduling.test.js test/notice.test.js test/fast-forward.test.js test/auto-playback.test.js test/builtin-layers.test.js test/prompt-components.test.js test/screenshot.test.js test/thumbnails.test.js test/progress.test.js test/environment.test.js test/storage.test.js test/facade-properties.test.js test/dom-boundaries.test.js test/initialization.test.js test/entry.test.js test/accessibility-button.test.js test/accessibility-focus.test.js test/accessibility-slider.test.js",
+    "test:unit": "node --test test/auto-thumbnail.test.js test/thumbnail-emitter.test.js test/thumbnail-runtime.test.js test/thumbnail-vendor.test.js test/thumbnail-lifecycle.test.js test/thumbnail-input.test.js test/thumbnail.test.js test/iframe-navigation.test.js test/iframe-boundaries.test.js test/iframe-lifecycle.test.js test/iframe.test.js test/mediabunny.test.js test/mediabunny-shim.test.js test/mediabunny-coordination.test.js test/mediabunny-video.test.js test/mediabunny-audio.test.js test/mediabunny-hls.test.js test/mediabunny-entry.test.js test/mediabunny-capability.test.js test/mediabunny-load.test.js test/mediabunny-input.test.js test/dpip.test.js test/dpip-lifecycle.test.js test/canvas.test.js test/canvas-lifecycle.test.js test/ambilight.test.js test/ambilight-lifecycle.test.js test/ambilight-proxy.test.js test/vast.test.js test/vast-lifecycle.test.js test/ads.test.js test/ads-lifecycle.test.js test/playback.test.js test/dash-control.test.js test/dash-contract.test.js test/dash-lifecycle.test.js test/dash-events.test.js test/hls-control.test.js test/audio-track.test.js test/public-behavior.test.js test/helpers.test.js test/chapter.test.js test/utils.test.js test/resource-scope.test.js test/instance-lifecycle.test.js test/options.test.js test/media-hosts.test.js test/plugins.test.js test/source.test.js test/playback-properties.test.js test/media-events.test.js test/template-resources.test.js test/core-vendor.test.js test/component-resources.test.js test/setting-model.test.js test/setting-layout.test.js test/setting-resources.test.js test/subtitle.test.js test/display-native.test.js test/display-video-fullscreen.test.js test/display-pip.test.js test/display-mini.test.js test/display-sizing.test.js test/display-orientation.test.js test/hotkey.test.js test/listener-registry.test.js test/global-events.test.js test/pointer-events.test.js test/gesture.test.js test/event-scheduling.test.js test/notice.test.js test/fast-forward.test.js test/auto-playback.test.js test/builtin-layers.test.js test/prompt-components.test.js test/screenshot.test.js test/thumbnails.test.js test/progress.test.js test/environment.test.js test/storage.test.js test/facade-properties.test.js test/dom-boundaries.test.js test/initialization.test.js test/entry.test.js test/accessibility-button.test.js test/accessibility-focus.test.js test/accessibility-slider.test.js",
     "test:coverage": "node --test test/coverage.test.js && node scripts/coverage.mjs",
     "test": "yarn test:node && yarn test:baseline",
     "test:browser": "playwright test",
@@ -84,7 +84,8 @@
     "test:iframe": "node --test test/iframe-navigation.test.js test/iframe-boundaries.test.js test/iframe.test.js test/iframe-lifecycle.test.js refactor/scripts/iframe-contract.test.mjs refactor/scripts/iframe-types.test.mjs",
     "test:iframe-types-package": "node refactor/scripts/iframe-package-types.mjs",
     "test:thumbnail": "node --test test/thumbnail-emitter.test.js test/thumbnail-runtime.test.js test/thumbnail-vendor.test.js test/thumbnail-lifecycle.test.js test/thumbnail-input.test.js test/thumbnail.test.js refactor/scripts/thumbnail-contract.test.mjs refactor/scripts/thumbnail-types.test.mjs",
-    "test:thumbnail-types-package": "node refactor/scripts/thumbnail-package-types.mjs"
+    "test:thumbnail-types-package": "node refactor/scripts/thumbnail-package-types.mjs",
+    "test:auto-thumbnail": "node --test test/auto-thumbnail.test.js refactor/scripts/auto-thumbnail-contract.test.mjs"
   },
   "browserslist": "last 1 Chrome version",
   "devDependencies": {

refactor/baselines/auto-thumbnail-failures.md

@@ -0,0 +1,78 @@
+# Auto-thumbnail 失败与原生对照
+
+`PKG-AUTO-THUMB-02` 补64项旧行为回归，八份固定夹具各执行八类问题。
+配合01的38项正常/分发契约，成功、失败、切源和销毁有可重跑对照。
+这里测试通过意味着 **成功复现旧缺陷**，不是候选已经修复。
+生产源码和包版本本步仍未变化，下一步03负责模块和生命周期修复。
+
+## 受控故障
+
+| 情况 | 实际旧行为 | 03应建立的候选断言 |
+| --- | --- | --- |
+| destroy期间等待Blob | 迟到回调继续写thumbnails，最终URL存活，decoder src/handlers未清 | 取消后不写UI、不创建URL；清理decoder/监听器/本任务URL |
+| 切源后旧metadata迟到 | 旧width/旧源覆盖新结果，两个任务URL同时留存 | 代际检查覆盖metadata/seek/Blob，只有当前任务可发布 |
+| 重复metadata | 创建三个独立decoder和三个未释放URL | 新任务替换旧任务，并明确保留预览与释放的时机 |
+| 编码回调逆序到达 | 完整→空白→半成品倒退，每次撤销前一可用URL | 串行或按代际/序号提交可用帧，不能倒退 |
+| toBlob返回null | 先撤销可用URL，再抛错；核心配置仍指向已失效URL | 验证Blob后才替换；失败有归属并释放临时资源 |
+| drawImage/toBlob同步抛错 | 异常逃逸，decoder和回调未清 | 出错后停止任务，继续清理，即使个别清理动作再抛错 |
+| getContext为null/原生media error | 前者稍后在drawImage抛错，后者没有处理者 | 失败不能静默挂起，不能冒充可用输出 |
+| 核心thumbnails setter抛错 | 新URL泄漏，后续帧继续工作 | 保留错误身份、收回新URL、停止失效任务及迟到副作用 |
+
+这些测试控制的是事件/编码回调，媒体对象不是原生解码器。无效数值、重入、跨实例、
+监听器安装/清理失败还需03的候选测试补齐，不能从上述八类推断穷尽覆盖。
+01中的旧高度参数、异步注册、CJS形状与类型推导问题保持独立处理。
+
+## 三浏览器真实证据
+
+最终9项原生测试覆盖1.0.1 main、1.1.0 main和冻结工作区main，分别运行
+Chromium153.0.8010.12、Firefox155.0、Windows WebKit26.6，均无重试/跳过。
+使用真实HTTP `/test/pattern.mp4`、原生seek、canvas.toBlob JPEG编码、BlobURL及img.decode
+读取像素。仅 **延迟交付原生编码结果** 来确定性验证竞争，没有替换视频帧或Blob内容。
+核心一侧是最小宿主替身，故这不是05的新旧核心联调、8082示例或真实Safari验收。
+
+每项原生证据都记录：0/2/4/6秒附近四次seek，五份编码（第一份空白），最终拼图
+800×45，四个已填格子的采样点，完整/空白两份回调的交付顺序，destroy前后更新及
+URL存活状态。最终URL在destroy后仍存活，迟到空白回调仍写入并撤销前一份URL。
+测试结束由测试方清理decoder和URL，明确不是旧插件完成了清理。
+
+### WebKit黑色采样没有作为能力豁免
+
+首次运行6项通过、3项WebKit像素断言失败；后续独立loadeddata+两次动画帧对照显示，
+不播放就draw也可能黑色（包括Chromium对照）。这不足以认定平台不支持。
+再加入可见、静音的独立video，等待播放前进至少0.25秒后暂停和draw，三个浏览器
+均得到彩色原始像素及JPEG；红色静态canvas→JPEG也通过。
+
+WebKit旧插件仍在四个采样点得到黑色JPEG，原生播放对照的原始/编码像素均有颜色。
+因此登记`AUTO-THUMB-PIXEL-01`为**旧抽帧路径缺陷**，根因仍需03用解码/帧就绪证据细化。
+没有将它归为不可用或跳过，也没有把“返回了JPEG”当成抽帧成功；不以四个采样点
+声称整幅图每个像素都是黑色。Firefox/Chromium旧插件的四格均采到彩色像素。
+
+最终测试严格断言这些旧版差异以及原生阳性对照，不是删除像素断言来通过。
+三个中间诊断运行（各6通过/3失败）和完整最终9通过报告/附件均独立归档。
+未来候选须验证可用像素，不能继承历史黑色结果作为成功标准。
+Windows的黑色历史断言明确限制在win32/WebKit，不将该平台现象硬编码成所有系统的
+WebKit行为；其他系统接受有正常采样的输出，若仍黑则必须是WebKit并保留同一原生阳性
+对照。最后这项平台边界调整经过定向lint和整组9项原生重跑；Linux托管CI本步未执行。
+
+### 03前置实验线索（不是候选验收）
+
+另用独立本地HTTP/原生video探测DOM挂载、loadeddata、播放、帧回调和seek条件。
+Windows WebKit26.6的该运行没有requestVideoFrameCallback；脱离DOM的等待/播放
+仍产生透明原始像素，挂载后追加seek可出现有效像素。display:none仍透明；
+将video渲染为1×1会把正常蓝色采样变成灰色平均值，**不能以非黑判定内容正确**。
+visibility:hidden且保留正常尺寸的探测保留了正常采样颜色，可作为03验证方向。
+首次seek位置还有偏离目标的记录，需要验证精确帧条件，不能直接把实验代码作为实现。
+原始记录在`.cache/auto-thumbnail-readiness-initial.{mjs,json,log}`和
+`.cache/auto-thumbnail-readiness-probe.{mjs,json,log}`；实验有明确不支持/超时结果，
+不计入上面9项验收，也不据此关闭像素风险。
+
+## 执行与接续
+
+- `yarn test:auto-thumbnail`：64项旧失败对照+38项冻结契约。
+- `yarn test:browser test/browser/auto-thumbnail.spec.js`：9项固定历史原生对照。
+- Node64项纳入`test:unit`；基线38项由`test:baseline`继续执行。
+- 03按入口注册、任务/源所有权、抽帧/编码、错误清理拆分，并保留有效旧调用；
+  新增的候选回归先在冻结旧版失败，再在源码/构建产物/原生浏览器通过。
+- 04迁严格TS与声明，05最终核心/真实设备，06实际tarball和完整demo，不合并冒充完成。
+
+详见[机器验证记录](auto-thumbnail-failures-validation.json)。本步不推送、不发布。

refactor/changes/2026-09-13-PKG-AUTO-THUMB-02-failures.md

@@ -0,0 +1,23 @@
+# PKG-AUTO-THUMB-02 旧失败回归与原生像素
+
+在八份冻结夹具上增加64项失败行为对照，覆盖销毁/切源/重复metadata/逆序编码/
+null Blob/draw与encode异常/缺context与media错误/核心setter异常。
+保留01正常契约，根脚本新增test:auto-thumbnail并将64项纳入test:unit，无新依赖。
+
+新增9项三浏览器原生HTTP/video/seek/JPEG/URL/像素测试，手动延迟原生编码结果交付以
+确定性复现销毁后更新和逆序覆盖。没有将宿主替身包装成核心联调，原生媒体内容未伪造。
+WebKit首轮像素失败后增加四格采样、独立loadeddata、可见静音播放和静态红色JPEG对照。
+播放/静态阳性对照均成功，旧抽帧路径四点仍黑，故作为待修缺陷而不是能力豁免。
+诊断失败运行完整保留，最终历史断言9项通过并不代表候选已修复。
+
+AUTO-THUMB-LIFE-01和AUTO-THUMB-ENCODE-01从source-observed变为reproduced，
+新增AUTO-THUMB-PIXEL-01；均保持open。无效输入/重入/跨实例等候选边界继续03补齐。
+下一步修改生产源码并建立候选成功标准；04保留独立TS/类型工作。
+
+见[故障表](../baselines/auto-thumbnail-failures.md)及
+[验证](../baselines/auto-thumbnail-failures-validation.json)。
+回退此提交只移除本步测试/脚本/记录；生产代码、发布版本、dist均未变。独立本地提交，
+不推送、不发布。
+
+最终完整CI1766项（1520单元+14工程+232基线）、339生产TS检查通过；历史原生9项通过，
+没有重试/跳过/未处理浏览器错误。源码修复是独立03任务，不把历史缺陷复现记为修复完成。

refactor/plan.md

@@ -4,7 +4,7 @@
 
 基线：`40fcda6a37d0049d42e49c1e64e70d4fd9ba5f7f`。总任务 222 项，范围 22 个包及工作区/示例。
 
-状态：todo 98 / doing 11 / blocked 0 / done 113 / deferred 0。风险 L/M/H 表示兼容风险，不表示工期。
+状态：todo 97 / doing 11 / blocked 0 / done 114 / deferred 0。风险 L/M/H 表示兼容风险，不表示工期。
 
 前置依赖是启动条件；验收是完成条件。任务可以继续拆分，但不能复用或悄悄删除旧 ID。
 
@@ -172,7 +172,7 @@
 | ID | 范围 / 步骤 | 前置依赖 | 交付物 | 验收条件 | 风险 | 状态 |
 | --- | --- | --- | --- | --- | --- | --- |
 | PKG-AUTO-THUMB-01 | artplayer-plugin-auto-thumbnail<br>核对包契约与历史用法 | BASE-05 | url/width/number/scale、异步工厂和渐进缩略图更新 | 源码/声明/README/demo/发布包差异已登记；公开形状和版本范围冻结 | H | done |
-| PKG-AUTO-THUMB-02 | artplayer-plugin-auto-thumbnail<br>建立特有行为与错误测试 | PKG-AUTO-THUMB-01, ENG-03, ENG-05 | 抽帧边界、短视频、失败、连续来源和销毁中的抽帧 | 旧版本行为可重跑，成功/失败/切源/销毁有必要断言 | H | todo |
+| PKG-AUTO-THUMB-02 | artplayer-plugin-auto-thumbnail<br>建立特有行为与错误测试 | PKG-AUTO-THUMB-01, ENG-03, ENG-05 | 抽帧边界、短视频、失败、连续来源和销毁中的抽帧 | 旧版本行为可重跑，成功/失败/切源/销毁有必要断言 | H | done |
 | PKG-AUTO-THUMB-03 | artplayer-plugin-auto-thumbnail<br>整理内部职责与资源 | PKG-AUTO-THUMB-02, CORE-09, CORE-19 | 隐藏 video、seek 队列、canvas 编码与 Blob URL 清理 | 结构变化和缺陷修复分开记录；原 API/事件/资源生命周期通过 | H | todo |
 | PKG-AUTO-THUMB-04 | artplayer-plugin-auto-thumbnail<br>迁移自有源码和公开类型 | PKG-AUTO-THUMB-03, ENG-04, ENG-06, CORE-07 | 抽帧结果和真实异步插件返回类型兼容 | 严格类型检查、旧消费样例通过；声明路径/导出和同步异步兼容 | H | todo |
 | PKG-AUTO-THUMB-05 | artplayer-plugin-auto-thumbnail<br>验证新旧核心和组合 | PKG-AUTO-THUMB-04, CORE-22 | 旧核心/候选核心预览、多次加载无过期缩略图覆盖 | 最终核心与原支持范围核心分别通过；设备/SDK 缺证据不能标完成 | H | todo |
@@ -495,6 +495,7 @@
 - PKG-AUDIO-04: [记录](changes/2026-09-12-PKG-AUDIO-04-types.md) [记录](baselines/audio-types-validation.json)
 - PKG-AUDIO-05: [记录](changes/2026-09-12-PKG-AUDIO-05-combinations.md) [记录](baselines/audio-combinations-first.json) [记录](baselines/audio-combinations-checkpoint.json) [记录](audio-validation.md)
 - PKG-AUTO-THUMB-01: [记录](baselines/auto-thumbnail-release.json) [记录](baselines/auto-thumbnail-contract.md) [记录](changes/2026-09-13-PKG-AUTO-THUMB-01-contract.md) [记录](baselines/auto-thumbnail-contract-validation.json)
+- PKG-AUTO-THUMB-02: [记录](baselines/auto-thumbnail-failures.md) [记录](baselines/auto-thumbnail-failures-validation.json) [记录](changes/2026-09-13-PKG-AUTO-THUMB-02-failures.md)
 - PKG-HLS-01: [记录](baselines/hls-control-contract.md) [记录](baselines/hls-control-release.json) [记录](changes/2026-09-11-PKG-HLS-01-contract.md)
 - PKG-HLS-02: [记录](hls-validation.md) [记录](baselines/hls-sdk.json) [记录](baselines/hls-validation.json) [记录](changes/2026-09-11-PKG-HLS-02-tests.md)
 - PKG-HLS-03: [记录](changes/2026-09-12-PKG-HLS-03-modules.md) [记录](baselines/hls-modules-validation.json) [记录](hls-validation.md)

refactor/progress.md

@@ -1,5 +1,17 @@
 # 进度与证据
 
+## PKG-AUTO-THUMB-02 完成：失败回归和原生抽帧对照
+
+64项旧行为测试覆盖8份冻结夹具的销毁/切源/重复metadata/逆序Blob/null Blob/
+draw与encode异常/缺context和media错误/setter异常。9项三浏览器原生HTTP/video/
+seek/JPEG/像素对照复现迟到更新；WebKit旧插件四点黑色，而播放及静态JPEG对照有色，
+登记为待修抽帧路径缺陷，不作为能力豁免。保留3次中间诊断失败报告和最终完整报告。
+完整CI1766项、339生产TS通过。新增test:auto-thumbnail，Node64项纳入test:unit。
+问题已复现并记录但源码尚未修复，03负责资源/抽帧重构；独立隐藏渲染实验仅作03线索。
+见[故障表](baselines/auto-thumbnail-failures.md)和[验证](baselines/auto-thumbnail-failures-validation.json)。
+222项：114 done、11 doing、97 todo；185风险，新增像素风险与已有相关风险均open。
+
+
 ## PKG-AUTO-THUMB-01 完成：自动缩略图发布与行为基线
 
 核实全部三个npm版本及16成员，冻结8份工作区输入。明确1.0.0缺main/legacy，

refactor/risk-table.md

@@ -186,5 +186,6 @@
 | AUTO-THUMB-TYPE-01 | open / 已复现 | Published declarations misdescribe async registration and switch height/number option fields across generations | PKG-AUTO-THUMB-04 |
 | AUTO-THUMB-EXPORT-01 | open / 已复现 | Published 1.0.1 CommonJS default namespace differs from the direct function exported by 1.1.0 | PKG-AUTO-THUMB-04, PKG-AUTO-THUMB-06 |
 | AUTO-THUMB-DIST-01 | open / 已复现 | Published 1.0.0 archive lacks declared main and legacy runtimes | PKG-AUTO-THUMB-06 |
-| AUTO-THUMB-LIFE-01 | open / 源码/产物事实 | Extraction tasks, decoder handlers and final object URLs lack source-switch and destroy ownership | PKG-AUTO-THUMB-02, PKG-AUTO-THUMB-03, PKG-AUTO-THUMB-05 |
-| AUTO-THUMB-ENCODE-01 | open / 源码/产物事实 | Unserialized encodes include blank output and lack media/canvas/input failure handling | PKG-AUTO-THUMB-02, PKG-AUTO-THUMB-03, PKG-AUTO-THUMB-05 |
+| AUTO-THUMB-LIFE-01 | open / 已复现 | Extraction tasks, decoder handlers and final object URLs lack source-switch and destroy ownership | PKG-AUTO-THUMB-02, PKG-AUTO-THUMB-03, PKG-AUTO-THUMB-05 |
+| AUTO-THUMB-ENCODE-01 | open / 已复现 | Unserialized encodes include blank output and lack media/canvas/input failure handling | PKG-AUTO-THUMB-02, PKG-AUTO-THUMB-03, PKG-AUTO-THUMB-05 |
+| AUTO-THUMB-PIXEL-01 | open / 已复现 | Historical auto-thumbnail yields black sampled JPEG cells on Windows WebKit while played native video and static JPEG controls yield color | PKG-AUTO-THUMB-03, PKG-AUTO-THUMB-05 |

refactor/risks.json

@@ -4051,7 +4051,7 @@
     {
       "id": "AUTO-THUMB-LIFE-01",
       "title": "Extraction tasks, decoder handlers and final object URLs lack source-switch and destroy ownership",
-      "confirmation": "source-observed",
+      "confirmation": "reproduced",
       "status": "open",
       "owners": [
         "PKG-AUTO-THUMB-02",
@@ -4061,15 +4061,19 @@
       "evidence": [
         "refactor/baselines/auto-thumbnail-release.json",
         "refactor/baselines/auto-thumbnail-contract.md",
-        "refactor/scripts/auto-thumbnail-contract.test.mjs"
+        "refactor/scripts/auto-thumbnail-contract.test.mjs",
+        "test/auto-thumbnail.test.js",
+        "refactor/baselines/auto-thumbnail-failures.md",
+        "refactor/baselines/auto-thumbnail-failures-validation.json"
       ],
       "compatibleResolution": "Cancel obsolete work and release owned resources while retaining live options and progressive usable sheet updates.",
-      "closureCriteria": "Delayed callbacks, repeated metadata, switching, destroy, multiple instances and failure cleanup are reproduced then pass source/artifacts and native browser checks."
+      "closureCriteria": "Delayed callbacks, repeated metadata, switching, destroy, multiple instances and failure cleanup are reproduced then pass source/artifacts and native browser checks.",
+      "workspaceState": "Task02 reproduces old failures with 64 controlled tests and native delayed JPEG callbacks. Candidate fixes, numeric validation, reentrancy and complete cleanup boundaries remain task03; status stays open."
     },
     {
       "id": "AUTO-THUMB-ENCODE-01",
       "title": "Unserialized encodes include blank output and lack media/canvas/input failure handling",
-      "confirmation": "source-observed",
+      "confirmation": "reproduced",
       "status": "open",
       "owners": [
         "PKG-AUTO-THUMB-02",
@@ -4079,10 +4083,31 @@
       "evidence": [
         "refactor/baselines/auto-thumbnail-release.json",
         "refactor/baselines/auto-thumbnail-contract.md",
-        "refactor/scripts/auto-thumbnail-contract.test.mjs"
+        "refactor/scripts/auto-thumbnail-contract.test.mjs",
+        "test/auto-thumbnail.test.js",
+        "refactor/baselines/auto-thumbnail-failures.md",
+        "refactor/baselines/auto-thumbnail-failures-validation.json"
       ],
       "compatibleResolution": "Preserve JPEG grid/time/scale while bounding jobs, sequencing valid updates and handling null Blob, invalid media and thrown callbacks.",
-      "closureCriteria": "Fault controls and native valid/corrupt media prove no stale sheet replacement, leaked URLs or unhandled async callbacks; capability limitations remain explicit."
+      "closureCriteria": "Fault controls and native valid/corrupt media prove no stale sheet replacement, leaked URLs or unhandled async callbacks; capability limitations remain explicit.",
+      "workspaceState": "Task02 reproduces old failures with 64 controlled tests and native delayed JPEG callbacks. Candidate fixes, numeric validation, reentrancy and complete cleanup boundaries remain task03; status stays open."
+    },
+    {
+      "id": "AUTO-THUMB-PIXEL-01",
+      "title": "Historical auto-thumbnail yields black sampled JPEG cells on Windows WebKit while played native video and static JPEG controls yield color",
+      "confirmation": "reproduced",
+      "status": "open",
+      "owners": [
+        "PKG-AUTO-THUMB-03",
+        "PKG-AUTO-THUMB-05"
+      ],
+      "evidence": [
+        "test/browser/auto-thumbnail.spec.js",
+        "refactor/baselines/auto-thumbnail-failures.md",
+        "refactor/baselines/auto-thumbnail-failures-validation.json"
+      ],
+      "compatibleResolution": "Establish actual decoded-frame readiness for the existing timeline/grid and preserve silent independent extraction; do not waive colored pixel checks as unsupported media.",
+      "closureCriteria": "Candidate source and artifacts generate usable sampled pixels on native browser controls with lifecycle checks; supported Safari and core combinations remain explicit final gates."
     }
   ]
 }

refactor/tasks.json

@@ -1755,11 +1755,15 @@
         "ENG-03",
         "ENG-05"
       ],
-      "status": "todo",
+      "status": "done",
       "risk": "H",
       "deliverable": "抽帧边界、短视频、失败、连续来源和销毁中的抽帧",
       "acceptance": "旧版本行为可重跑，成功/失败/切源/销毁有必要断言",
-      "evidence": []
+      "evidence": [
+        "baselines/auto-thumbnail-failures.md",
+        "baselines/auto-thumbnail-failures-validation.json",
+        "changes/2026-09-13-PKG-AUTO-THUMB-02-failures.md"
+      ]
     },
     {
       "id": "PKG-AUTO-THUMB-03",

test/auto-thumbnail.test.js

@@ -0,0 +1,140 @@
+import assert from 'node:assert/strict'
+// eslint-disable-next-line test/no-import-node-test -- Frozen historical regressions use the repository Node runner.
+import test from 'node:test'
+import { autoThumbnailEnvironment, autoThumbnailHistorical } from './helpers/auto-thumbnail.js'
+
+for (const implementation of await autoThumbnailHistorical()) {
+  test(`Auto-thumbnail ${implementation.name} historical: destroy leaves pending encode and final URL alive`, async () => {
+    const env = autoThumbnailEnvironment(implementation)
+    await env.factory({ number: 2 })(env.art)
+    env.art.emit('video:loadedmetadata')
+    env.metadata()
+    const video = env.videos[0]
+    env.art.emit('destroy')
+    env.finish()
+    assert.equal(env.updates.length, 1)
+    assert.equal(env.urls.size, 1)
+    assert.equal(env.listeners.get('video:loadedmetadata').size, 1)
+    assert.equal(typeof video.onloadedmetadata, 'function')
+    assert.equal(typeof video.onseeked, 'function')
+    assert.equal(video.src, 'original.mp4')
+    assert.equal(env.operations.filter(item => item.name === 'pause' || item.name === 'load').length, 0)
+    env.art.emit('destroy')
+    assert.equal(env.urls.size, 1)
+  })
+
+  test(`Auto-thumbnail ${implementation.name} historical: delayed old metadata overwrites a newer source sheet`, async () => {
+    const env = autoThumbnailEnvironment(implementation)
+    const options = { number: 2, width: 80 }
+    await env.factory(options)(env.art)
+    env.art.emit('video:loadedmetadata')
+    const oldVideo = env.videos[0]
+    env.art.option.url = 'replacement.mp4'
+    options.width = 160
+    env.art.emit('restart')
+    env.art.emit('video:loadedmetadata')
+    env.metadata(env.videos[1])
+    env.finish(0, { source: 'new' })
+    assert.equal(env.updates.at(-1).width, 160)
+    env.metadata(oldVideo)
+    env.finish(1, { source: 'old' })
+    assert.equal(env.updates.at(-1).width, 80)
+    assert.equal(env.urls.get(env.updates.at(-1).url).source, 'old')
+    assert.equal(env.urls.size, 2, 'Separate jobs never revoke each other or release the latest stale sheet')
+  })
+
+  test(`Auto-thumbnail ${implementation.name} historical: repeated metadata opens independent decoders without closing previous jobs`, async () => {
+    const env = autoThumbnailEnvironment(implementation)
+    await env.factory({ number: 1 })(env.art)
+    for (let index = 0; index < 3; index++) {
+      env.art.emit('video:loadedmetadata')
+      env.metadata()
+      env.finish(index)
+    }
+    assert.equal(env.videos.length, 3)
+    assert.equal(env.urls.size, 3)
+    assert.equal(env.operations.some(item => item.name === 'pause' || item.name === 'load'), false)
+    assert.equal(env.videos.every(video => typeof video.onseeked === 'function'), true)
+  })
+
+  test(`Auto-thumbnail ${implementation.name} historical: reverse Blob delivery replaces a complete sheet with its initial blank snapshot`, async () => {
+    const env = autoThumbnailEnvironment(implementation)
+    await env.factory({ number: 2 })(env.art)
+    env.art.emit('video:loadedmetadata')
+    env.metadata()
+    env.seeked()
+    env.seeked()
+    assert.equal(env.blobs.length, 3, 'All native encodes can be pending together')
+    env.finish(2, { frames: 2 })
+    const completed = env.updates.at(-1).url
+    env.finish(0, { frames: 0 })
+    assert.equal(env.urls.has(completed), false)
+    assert.equal(env.urls.get(env.updates.at(-1).url).frames, 0)
+    env.finish(1, { frames: 1 })
+    assert.equal(env.urls.get(env.updates.at(-1).url).frames, 1)
+  })
+
+  test(`Auto-thumbnail ${implementation.name} historical: null Blob revokes the previous usable URL before throwing`, async () => {
+    const env = autoThumbnailEnvironment(implementation)
+    await env.factory({ number: 2 })(env.art)
+    env.art.emit('video:loadedmetadata')
+    env.metadata()
+    env.finish()
+    const sheet = env.art.thumbnails
+    env.seeked()
+    assert.throws(() => env.finish(1, null), /Blob required/)
+    assert.equal(env.urls.has(sheet.url), false)
+    assert.equal(env.art.thumbnails, sheet, 'Public state still references the revoked URL')
+    assert.equal(typeof env.videos[0].onseeked, 'function')
+  })
+
+  test(`Auto-thumbnail ${implementation.name} historical: draw and encode exceptions escape and retain decoder callbacks`, async () => {
+    for (const phase of ['draw', 'encode']) {
+      const env = autoThumbnailEnvironment(implementation)
+      const failure = new Error(`${phase} failed`)
+      await env.factory({ number: 2 })(env.art)
+      env.art.emit('video:loadedmetadata')
+      if (phase === 'draw') {
+        env.metadata()
+        env.controls.drawError = failure
+        assert.throws(() => env.seeked(), error => error === failure)
+      }
+      else {
+        env.controls.encodeError = failure
+        assert.throws(() => env.metadata(), error => error === failure)
+      }
+      assert.equal(typeof env.videos[0].onloadedmetadata, 'function')
+      assert.equal(env.videos[0].src, 'original.mp4')
+      assert.equal(env.operations.some(item => item.name === 'pause' || item.name === 'load'), false)
+    }
+  })
+
+  test(`Auto-thumbnail ${implementation.name} historical: missing context and native media errors have no failure owner`, async () => {
+    const env = autoThumbnailEnvironment(implementation)
+    await env.factory({ number: 2 })(env.art)
+    env.art.emit('video:loadedmetadata')
+    env.controls.nullContext = true
+    env.metadata()
+    assert.throws(() => env.seeked(), /drawImage/)
+    assert.equal(env.videos[0].onerror, null)
+    assert.equal(env.operations.some(item => item.name === 'pause' || item.name === 'load'), false)
+  })
+
+  test(`Auto-thumbnail ${implementation.name} historical: thumbnail setter failure leaks the new URL and does not cancel later work`, async () => {
+    const env = autoThumbnailEnvironment(implementation)
+    const failure = new Error('thumbnail setter failed')
+    await env.factory({ number: 2 })(env.art)
+    env.art.emit('video:loadedmetadata')
+    env.metadata()
+    env.controls.updateError = failure
+    assert.throws(() => env.finish(), error => error === failure)
+    assert.equal(env.urls.size, 1)
+    assert.equal(env.updates.length, 0)
+    env.controls.updateError = null
+    env.seeked()
+    env.finish(1)
+    assert.equal(env.updates.length, 1)
+    env.art.emit('destroy')
+    assert.equal(env.urls.size, 1)
+  })
+}

test/browser/auto-thumbnail.spec.js

@@ -0,0 +1,195 @@
+import process from 'node:process'
+import { hash } from '../../refactor/scripts/releases.mjs'
+import { autoThumbnailHistorical } from '../helpers/auto-thumbnail.js'
+import { expect, test } from './fixtures.js'
+
+const implementations = (await autoThumbnailHistorical()).filter(item => ['published-1.0.1-main', 'published-1.1.0-main', 'frozen-workspace-js'].includes(item.name))
+
+for (const implementation of implementations) {
+  test(`Auto-thumbnail ${implementation.name}: native JPEG callbacks outlive destroy and can restore the blank sheet`, async ({ page, browserName }, testInfo) => {
+    await page.goto('/test/player.html?core=published')
+    await page.setContent('<!doctype html><div id="probe"></div>')
+    await page.addScriptTag({ content: implementation.code })
+    await page.evaluate(async () => {
+      const createElement = document.createElement.bind(document)
+      const createUrl = URL.createObjectURL.bind(URL)
+      const revokeUrl = URL.revokeObjectURL.bind(URL)
+      const toBlob = HTMLCanvasElement.prototype.toBlob
+      const probe = window.probe = { videos: [], canvases: [], encodes: [], updates: [], urls: new Map(), revoked: [], seeks: [], destroyed: false }
+      document.createElement = function (name, ...args) {
+        const element = createElement(name, ...args)
+        if (name === 'video') {
+          probe.videos.push(element)
+          element.addEventListener('seeked', () => probe.seeks.push(element.currentTime))
+        }
+        if (name === 'canvas')
+          probe.canvases.push(element)
+        return element
+      }
+      HTMLCanvasElement.prototype.toBlob = function (callback, type, quality) {
+        const index = probe.encodes.length
+        const record = { index, blob: null, callback, type, width: this.width, height: this.height }
+        probe.encodes.push(record)
+        return toBlob.call(this, blob => record.blob = blob, type, quality)
+      }
+      URL.createObjectURL = (blob) => {
+        const url = createUrl(blob)
+        probe.urls.set(url, blob)
+        return url
+      }
+      URL.revokeObjectURL = (url) => {
+        probe.revoked.push(url)
+        probe.urls.delete(url)
+        revokeUrl(url)
+      }
+      const listeners = new Map()
+      const art = {
+        option: { url: '/test/pattern.mp4' },
+        on(name, callback) {
+          if (!listeners.has(name))
+            listeners.set(name, new Set())
+          listeners.get(name).add(callback)
+        },
+        emit(name) {
+          for (const callback of listeners.get(name) || []) callback()
+        },
+        get thumbnails() { return probe.updates.at(-1) },
+        set thumbnails(value) { probe.updates.push({ ...value, afterDestroy: probe.destroyed }) },
+      }
+      probe.art = art
+      probe.nativeToBlob = toBlob
+      probe.restore = () => {
+        document.createElement = createElement
+        HTMLCanvasElement.prototype.toBlob = toBlob
+        URL.createObjectURL = createUrl
+        URL.revokeObjectURL = revokeUrl
+      }
+      probe.result = await window.artplayerPluginAutoThumbnail({ width: 80, number: 4 })(art)
+      art.emit('video:loadedmetadata')
+    })
+    await expect.poll(() => page.evaluate(() => window.probe.encodes.filter(item => item.blob).length)).toBe(5)
+    const evidence = await page.evaluate(async () => {
+      const probe = window.probe
+      async function pixels(blob) {
+        const image = document.createElement('img')
+        const url = URL.createObjectURL(blob)
+        image.src = url
+        await image.decode()
+        const canvas = document.createElement('canvas')
+        canvas.width = image.naturalWidth
+        canvas.height = image.naturalHeight
+        const ctx = canvas.getContext('2d')
+        ctx.drawImage(image, 0, 0)
+        const samples = Array.from({ length: 4 }, (_, index) => [...ctx.getImageData(40 + index * 80, 22, 1, 1).data])
+        URL.revokeObjectURL(url)
+        return { width: canvas.width, height: canvas.height, pixel: samples[0], samples, type: blob.type }
+      }
+      const blanks = await pixels(probe.encodes[0].blob)
+      const final = await pixels(probe.encodes[4].blob)
+      const controlVideo = document.createElement('video')
+      controlVideo.crossOrigin = 'anonymous'
+      controlVideo.muted = true
+      document.body.append(controlVideo)
+      await new Promise((resolve, reject) => {
+        const timeout = setTimeout(() => reject(new Error('Native control did not load')), 5000)
+        controlVideo.onloadeddata = () => {
+          clearTimeout(timeout)
+          resolve()
+        }
+        controlVideo.onerror = () => {
+          clearTimeout(timeout)
+          reject(new Error(`Native control media error ${controlVideo.error?.code}`))
+        }
+        controlVideo.src = '/test/pattern.mp4'
+      })
+      await controlVideo.play()
+      await new Promise((resolve, reject) => {
+        const timeout = setTimeout(() => reject(new Error('Native control playback did not advance')), 5000)
+        const check = () => {
+          if (controlVideo.currentTime >= 0.25) {
+            clearTimeout(timeout)
+            resolve()
+          }
+          else {
+            requestAnimationFrame(check)
+          }
+        }
+        check()
+      })
+      controlVideo.pause()
+      const controlCanvas = document.createElement('canvas')
+      controlCanvas.width = 800
+      controlCanvas.height = 45
+      const controlContext = controlCanvas.getContext('2d')
+      controlContext.drawImage(controlVideo, 0, 0, 80, 45)
+      const rawPixel = [...controlContext.getImageData(40, 22, 1, 1).data]
+      const controlBlob = await new Promise(resolve => probe.nativeToBlob.call(controlCanvas, resolve, 'image/jpeg'))
+      const native = { readyState: controlVideo.readyState, currentTime: controlVideo.currentTime, rawPixel, ...await pixels(controlBlob) }
+      controlContext.fillStyle = 'red'
+      controlContext.fillRect(0, 0, 80, 45)
+      const staticBlob = await new Promise(resolve => probe.nativeToBlob.call(controlCanvas, resolve, 'image/jpeg'))
+      const staticControl = await pixels(staticBlob)
+      probe.encodes[4].callback(probe.encodes[4].blob)
+      const good = probe.updates.at(-1).url
+      probe.destroyed = true
+      probe.art.emit('destroy')
+      const outstandingAfterDestroy = probe.urls.size
+      probe.encodes[0].callback(probe.encodes[0].blob)
+      const bad = probe.updates.at(-1).url
+      const result = {
+        blanks,
+        final,
+        native,
+        staticControl,
+        seeks: probe.seeks,
+        updates: probe.updates.map(({ url, ...rest }) => rest),
+        outstandingAfterDestroy,
+        goodRevoked: !probe.urls.has(good),
+        staleUrlLive: probe.urls.has(bad),
+        result: probe.result,
+        videoState: { src: probe.videos[0].getAttribute('src'), readyState: probe.videos[0].readyState, width: probe.videos[0].videoWidth, seekHandler: typeof probe.videos[0].onseeked, metadataHandler: typeof probe.videos[0].onloadedmetadata },
+      }
+      // The test owns the cleanup because the historical plugin does not.
+      for (const video of probe.videos) {
+        video.pause()
+        video.removeAttribute('src')
+        video.load()
+        video.remove()
+      }
+      for (const url of [...probe.urls.keys()]) URL.revokeObjectURL(url)
+      probe.restore()
+      return result
+    })
+    await testInfo.attach('auto-thumbnail-native-historical', { contentType: 'application/json', body: JSON.stringify({ implementation: implementation.name, sha256: hash(implementation.code), scope: 'Native HTTP video, seeking and JPEG pixels with controlled delivery of native toBlob results; player-facing host is a stub, not a core integration result.', ...evidence }) })
+    expect(evidence.result).toEqual({ name: 'artplayerPluginAutoThumbnail' })
+    expect(evidence.blanks.type).toBe('image/jpeg')
+    expect(evidence.final.width).toBe(800)
+    expect(evidence.final.height).toBe(45)
+    expect(evidence.blanks.pixel.slice(0, 3).every(value => value < 5)).toBe(true)
+    expect(evidence.staticControl.pixel[0]).toBeGreaterThan(240)
+    expect(evidence.staticControl.pixel[1]).toBeLessThan(10)
+    expect(evidence.staticControl.pixel[2]).toBeLessThan(10)
+    expect(evidence.native.currentTime).toBeGreaterThanOrEqual(0.25)
+    expect(evidence.native.rawPixel.slice(0, 3).some(value => value > 30)).toBe(true)
+    expect(evidence.native.pixel.slice(0, 3).some(value => value > 30)).toBe(true)
+    const blackSamples = evidence.final.samples.every(pixel => pixel.slice(0, 3).every(value => value < 5))
+    if (browserName === 'webkit' && process.platform === 'win32')
+      expect(blackSamples).toBe(true)
+    if (blackSamples) {
+      expect(browserName).toBe('webkit')
+      testInfo.annotations.push({ type: 'historical-media-defect', description: 'Historical plugin JPEG samples are black, while independent played HTTP video and static red canvas yield colored JPEGs. This is an extraction-path defect, not a waived browser capability.' })
+    }
+    else {
+      expect(evidence.final.samples.every(pixel => pixel.slice(0, 3).some(value => value > 30))).toBe(true)
+    }
+    expect(evidence.seeks).toHaveLength(4)
+    expect(evidence.outstandingAfterDestroy).toBe(1)
+    expect(evidence.updates.map(item => item.afterDestroy)).toEqual([false, true])
+    expect(evidence.goodRevoked).toBe(true)
+    expect(evidence.staleUrlLive).toBe(true)
+    expect(evidence.videoState.src).toBe('/test/pattern.mp4')
+    expect(evidence.videoState.width).toBeGreaterThan(0)
+    expect(evidence.videoState.seekHandler).toBe('function')
+    expect(evidence.videoState.metadataHandler).toBe('function')
+  })
+}