[REPLAY] Discard mouse/touch event without x/y position

[ThibautGeriz]

Motivation

We have a bunch of error in the player where we have mouse record without x/y with numeric value.

The hypothesis is that the event are not generated by the browser but by JS using dispatchEvent

Changes

• Discard mouse/touch event without x/y position
• Add telemetry with isTrusted to validate/invalidate the theory

Testing

• Local
• Staging
• Unit
• End to end

---

I have gone over the contributing documentation.

[codecov-commenter]

Codecov Report

Merging #1993 (1ab44fb) into main (a6533af) will increase coverage by 0.04%.
The diff coverage is 92.30%.

@@            Coverage Diff             @@
##             main    #1993      +/-   ##
==========================================
+ Coverage   93.37%   93.41%   +0.04%     
==========================================
  Files         145      145              
  Lines        5511     5515       +4     
  Branches     1256     1258       +2     
==========================================
+ Hits         5146     5152       +6     
+ Misses        365      363       -2     

Impacted Files	Coverage Δ
packages/rum/src/domain/record/observers.ts	81.86% <92.30%> (+4.86%)	⬆️
...s/rum-core/src/domain/contexts/pageStateHistory.ts	80.48% <0.00%> (-12.20%)	⬇️
...rum-core/src/domain/contexts/foregroundContexts.ts	90.76% <0.00%> (-3.08%)	⬇️

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[BenoitZugmeyer]

💬 suggestion: ‏the element does not need to be focusable for this test, you could remove the tabindex attribute

💬 suggestion: ‏in fact, you don't need an element for this test, you could simply dispatch the event on document.body, so you could remove sandbox and a

[BenoitZugmeyer]

❓ question: ‏ What will those telemetry logs used for?

💬 suggestion: ‏ If it's to see whether ignoring untrusted events would help, I would suggest emiting a telemetry log only when the event is untrusted. This would reduce the amount of unneeded logs messages.

Suggested change

	addTelemetryDebug('mouse/touch event without x/y', {
	isTrusted: event.isTrusted,
	position: { x, y },
	})
	if (event.isTrusted) {
	addTelemetryDebug('mouse/touch event without x/y', {
	position: { x, y },
	})
	}

[ThibautGeriz]

I disagree, if we have event without x/y that are both trusted and not trusted I would like to know about it

[ThibautGeriz]

What will those telemetry logs used for?

I want to know if the next major release will fix this issue for and we can remove that code

[BenoitZugmeyer]

We know that some untrusted events don't have coordinates. I don't think we need to confirm that anymore, since we can easily reproduce it.

Now, what I'm worried about is the amount of telemetry logs that could be sent. If you still think that we should add a log when an untrusted event don't have coordinates, I would suggest to limit the amount of telemetry debug by only logging the first one, something like:

let wasEventWithoutCoordinatesLogSent = false

function tryComputeCoordinates(event) {
  ...
  if (!wasEventWithoutCoordinatesLogSent && !Number.isFinite(...) && ...) {
    wasEventWithoutCoordinatesLogSent = true
    addTelemetryDebug('mouse/touch event without x/y', {
      isTrusted: event.isTrusted,
      position: { x, y },
    })
  }
  ...
}

[ThibautGeriz]

Alright I see your point, I will only send the telemetry if event is trusted

[BenoitZugmeyer]

🥜 nitpick: ‏ ‏you could also move the telemetry debug in tryComputeCoordinates