Gesture dispose() not called when exception thrown in handleUp(), causing workspace interaction to freeze ?

[CN Laster]

Hello everyone, I have a question.

If an exception is thrown during the execution of Gesture.handleUp() before dispose() is called, the gesture will not be properly cleaned up.

This leaves the workspace in a broken state where all subsequent user interactions are blocked because the touch identifier remains set and event listeners are not unbound.

Current Code (core/gesture.ts:521-569)  


···

handleUp(e: PointerEvent) {

if (!this.isDragging()) {

this.handleTouchEnd(e);

}

if (!this.isMultiTouch() || this.isDragging()) {

if (!Touch.shouldHandleEvent(e)) {

return;

}

this.updateFromEvent(e);

Touch.longStop();

if (this.isEnding_) {

console.log("Trying to end a gesture recursively.");

return;

}

this.isEnding_ = true;

// PROBLEM: If any of these throw an exception, dispose() won't be called

if (this.dragger) {

this.dragger.onDragEnd(e, this.currentDragDeltaXY);

} else if (this.workspaceDragger) {

this.workspaceDragger.endDrag(this.currentDragDeltaXY);

} else if (this.isBubbleClick()) {

// ...

} // ... more conditionals

e.preventDefault();

e.stopPropagation();

this.dispose(); // ⚠️ Never reached if exception thrown above

} else {

e.preventDefault();

e.stopPropagation();

this.dispose(); // ⚠️ Never reached if exception thrown above

}

}
···

[Christopher Allen]

Hello,

If an exception is thrown during the execution of Gesture.handleUp() before dispose() is called, the gesture will not be properly cleaned up.

This leaves the workspace in a broken state where all subsequent user interactions are blocked because the touch identifier remains set and event listeners are not unbound.

There might be two different issues here:

1. Is there a bug in core Blockly that is causing such an exception to be thrown?  If so we'd appreciate it if you filed a bug report with enough details that we can reproduce it.
2. Separately, it does seem like it might be a good idea to make handleUp more robust.  Would you be so kind as to file a separate issue noting the potential problem and requesting that we add a try / finally here—and/or send us a PR to do so yourself?

Best wishes,

Christopher