axe drag fails on Xcode 26.5: FBSimulatorHIDEvent does not support touch move events #59

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1. coderabbitai commented on Jun 12, 2026

   

   coderabbitaiBot

   on Jun 12, 2026 – with coderabbitai

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   🔗 Related PRs

   #9 - Add tap by accessibility id/label [merged]
   #20 - fix(touch): make long press gestures reliable [merged]
   #39 - fix(describe-ui): Add point option support [merged]
   #44 - fix(commands): orientation-aware coords for both rotated devices and letterboxed landscape-only apps (#5) [merged]
   #49 - feat(drag): Add precision drag and slider commands [merged]

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2. the-simian commented on Jul 1, 2026

   

   the-simian

   on Jul 1, 2026

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   Reproducible with axe slider as well, and on an older Xcode than the report: Xcode 16.2 (16C5032a), macOS 14.6.1, AXe 1.7.1 via Homebrew, iPhone 16 Pro simulator on iOS 18.3. So this does not appear to be Xcode 26-specific.

   Repro with an open-source app

   The react-native-webrtc-kaleidoscope demo ships sliders that carry stable accessibility identifiers, which makes the failure easy to reproduce by id:

   git clone https://github.com/simiancraft/react-native-webrtc-kaleidoscope
   cd react-native-webrtc-kaleidoscope/demo
   npm install
   npm run ios          # expo run:ios against a booted simulator

   In the demo select Shaders > Sky > Dawn; the SKY panel exposes per-channel color sliders. Then:

   $ axe slider --id kld.clouds-dawn.sky.uSkyLowColor.r --value 10 --udid <udid>
   Error: CLIError(errorDescription: "FBSimulatorHIDEvent does not support touch move events.")

   Any slider reproduces it; this app just provides addressable ones.

   Where the error originates

   Sources/AXe/Utilities/HIDInteractor.swift: touchMoveEvent resolves touchMoveAtX:y: on FBSimulatorHIDEvent dynamically via NSSelectorFromString and throws this exact CLIError when the selector is missing. Both slider and drag route through performCompositeDrag (touch down, N touch moves, touch up), so both fail whenever the linked FBSimulatorControl build does not expose that method.

   A fix path that works today

   On the same machine the composite swipe event is fine: axe swipe along the slider's track (from the current thumb position, derived from the element's frame and AXValue, to the target fraction) moves the thumb reliably, and re-reading AXValue confirms it. Against the same slider:

   axe swipe --start-x 379 --start-y 484 --end-x 66 --end-y 484 --duration 0.5 --udid <udid>

   So one option is for performCompositeDrag to fall back to FBSimulatorHIDEvent.swipe(...) when touchMoveAtX:y: is unavailable; Slider.swift already polls AXValue after the drag, so the verification half of that path is in place.

   Happy to test a branch.