readest/apps/readest-app/.claude/memory/issue-4584-tap-death-investigation.md

name, description, metadata

name	description	metadata
issue-4584-tap-death-investigation	#4584 single-taps-dead-after-picture-zoom: isPopuped self-heals (red herring), likely WebView-148-specific, plus Android emulator/CDP gesture-verification gotchas	node_type type originSessionId memory project a41b6cab-c0f3-4740-a4c0-61a10b68fc09

#4584 (Android): after using picture zoom (long-press image → ImageViewer → close), single taps stop registering until app restart while long-press keeps working. OP on Android 16 / WebView 148. NOT root-caused / NOT fixed. PR #4600 only adds single-tap as a second way into the viewer (see tap-to-open-image-table-4600); it does not fix the tap-death.

Red herring — don't "fix" isPopuped. An adversarial analysis pointed at useTextSelector.ts handleSingleClick's isPopuped branch consuming a tap without resetting the flag (unlike its isTextSelected/isUpToPopup siblings). But it self-heals: the branch calls handleDismissPopup() → showingPopup false → handleShowPopup(false) → isPopuped false after 500ms. And the uncancelled 500ms timer in handleShowPopup always converges isPopuped to the FINAL showingPopup (timers are same-delay FIFO), so it can't strand isPopuped=true with showingPopup=false. Net effect is at most a one-tap glitch, NOT permanent. Resetting it in the branch is harmless but does NOT explain #4584.

Likely WebView-148-specific: the OP reproduces; the maintainer's Xiaomi and the Pixel_9_Pro emulator (WebView 133) do NOT. A stronger unverified permanent-death candidate is isInstantAnnotating/scrollLocked getting stuck when the ImageViewer overlay swallows the pointerup (needs instant-annotation enabled).

Android emulator gesture-verification gotchas (this machine):

• Host-GPU Pixel_9_Pro AVD CRASHES on rapid pinch (Vulkan bad_function_call); a re-launch can hang at Vulkan init. -gpu swiftshader_indirect boots reliably but is too slow for the WebView reader → repeated "Input dispatching timed out for FocusEvent" ANRs under automation. That ANR is an EMULATOR ARTIFACT, not app code (JS stays responsive; CPU runs native arm64 on Apple Silicon, only the GPU is swiftshader; CPU profile of page-turns is light; full-screen backdrop-blur made zero frame-time difference).
• CDP Input.dispatchTouchEvent CANNOT trigger the WebView's native text-SELECTION gesture, so the annotation popup never appears (blocks reproducing selection-driven bugs). It also leaves screenX=0, so handlePageFlip treats every synthetic tap as left/prev() (no-op at page 1 → navigate mid-book to test page-turns via relocate).
• Native adb shell input tap does NOT reach the WebView's click pipeline.
• Long-press via CDP only works if you HOLD the touch on one open connection and poll (a touchStart→sleep→touchEnd across separate node invocations releases too early).
• Drive the live on-device WebView: adb forward tcp:9222 localabstract:webview_devtools_remote_<pid>
  • a ws CDP client; the debug APK exposes the socket. VIEW-intent a pushed EPUB via its MediaStore content://.../<id> to import it.