fix(touch): prevent infinite loop on multi-touch drag

[AbhinavKRN]

The basics

• I validated my changes

The details

Resolves

Fixes #8396

Proposed Changes

This pull request addresses a RangeError: Maximum call stack size exceeded error that occurs when users attempt to drag a block with multiple fingers on a workspace where zoom controls/wheel are disabled. The change modifies the handling of touch events to prevent an infinite loop.

Reason for Changes

The error occurs due to the interaction between the handleMove and handleTouchMove functions. If a multi-touch event does not meet the conditions for a pinch zoom, the functions call each other recursively, resulting in a maximum call stack size exceeded error. This issue has caused disruptions, triggering alarms in our monitoring system and impacting our on-call engineers.

Test Coverage

I have tested the changes manually by:

1. Using a touch device.
2. Disabling zoom wheel and controls.
3. Adding a block to the workspace.
4. Using two fingers to attempt to drag the block.
   The RangeError no longer occurs, and the drag operation works as expected. Additional unit tests have been created to simulate multi-touch events and verify that no infinite loop occurs.

Documentation

No documentation updates are required as this change only affects internal event handling.

Additional Information

The issue was detected using NewRelic, which reported an increase in JS errors since migrating additional labs to Google Blockly. The proposed solution involves modifying the handleTouchMove function to handle the move operation directly when pinch zoom conditions are not met, preventing the recursive call loop.

Detailed Analysis

The problem occurs in the interaction between handleMove and handleTouchMove:

handleMove Function:

handleMove(e: PointerEvent) {
  if ((this.isDragging() && Touch.shouldHandleEvent(e)) || !this.isMultiTouch()) {
    // Handle single touch or drag...
  } else if (this.isMultiTouch()) {
    this.handleTouchMove(e);
    Touch.longStop();
  }
}

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[BeksOmega]

Heya @AbhinavKRN This change looks good =) Can you go ahead and sign the CLA for me so I can get it merged?

[AbhinavKRN]

@BeksOmega Can you tell me how to sign CLA, as i'm new to this term.

[BeksOmega]

Check out the message from above @AbhinavKRN =)

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[AbhinavKRN]

@BeksOmega Done with CLA!

[AbhinavKRN]

@BeksOmega there was some error with prettier, i have resolved it again. Can you check it.

[BeksOmega]

Thank you again for the work on this @AbhinavKRN !