1740798 - Input.dispatchMouseEvent() doesn't wait for mouse event to be processed before returning

Status: RESOLVED FIXED

(Remote Protocol :: CDP, defect, P3)

Description

[Henrik Skupin [:whimboo][⌚️UTC+2]]

There is a problem with the Input.dispatchMouseEvent() method. It returns too early and as such a next command might race because a result as expected to be set by the page's click event handler isn't present yet.

When we trigger the click via EventUtils.synthesizeMouse() we do not wait until it actually has been processes by a possible event listener on that page. An example can be seen here:

https://treeherder.mozilla.org/logviewer?job_id=357808344&repo=try&lineNumber=1264-1274

[task 2021-11-11T20:48:39.996Z] PID 423 | 1636663719987	CDP	TRACE	CDPConnection {4d6e0301-4bed-4e08-8b6c-620f9f5bcde0} -> {"sessionId":"6625c662-2a7e-4450-8290-1e30ffc8a430","method":"Input.dispatchMouseEvent","params":{"type":"mouseReleased","button":"left","x":50,"y":19.5,"modifiers":0,"clickCount":1},"id":197}
[task 2021-11-11T20:48:39.996Z] PID 423 | 
[task 2021-11-11T20:48:39.996Z] PID 423 | *** ownerglobal: [object Window]
[task 2021-11-11T20:48:39.997Z] PID 423 | 
[task 2021-11-11T20:48:39.997Z] PID 423 | *** Received event: mouseup
[task 2021-11-11T20:48:39.998Z] PID 423 | 1636663719988	CDP	TRACE	CDPConnection {4d6e0301-4bed-4e08-8b6c-620f9f5bcde0} <- {"id":197,"result":{},"sessionId":"6625c662-2a7e-4450-8290-1e30ffc8a430"}
[task 2021-11-11T20:48:39.998Z] PID 423 | 1636663719988	CDP	TRACE	CDPConnection {4d6e0301-4bed-4e08-8b6c-620f9f5bcde0} <- {"method":"Target.receivedMessageFromTarget","params":{"sessionId":"6625c662-2a7e-4450-8290-1e30ffc8a430","message":"{\"id\":197,\"result\":{}}"}}
[task 2021-11-11T20:48:39.998Z] PID 423 | 1636663719989	CDP	TRACE	CDPConnection {4d6e0301-4bed-4e08-8b6c-620f9f5bcde0} -> {"sessionId":"6625c662-2a7e-4450-8290-1e30ffc8a430","method":"Runtime.callFunctionOn","params":{"functionDeclaration":"() =>  ... tion_script__\n","executionContextId":3,"arguments":[],"returnByValue":true,"awaitPromise":true,"userGesture":true},"id":198}
[task 2021-11-11T20:48:39.998Z] PID 423 | 
[task 2021-11-11T20:48:39.998Z] PID 423 | ** button was clicked - updating result
[task 2021-11-11T20:48:39.998Z] PID 423 | 1636663719993	CDP	TRACE	CDPConnection {4d6e0301-4bed-4e08-8b6c-620f9f5bcde0} <- {"id":198,"result":{"result":{"type":"string","value":"Was not clicked","description":"Was not clicked"}},"sessionId":"6625c662-2a7e-4450-8290-1e30ffc8a430"}

This will fix a couple of Puppeteer tests.

Comment 1

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Given our code in Input.dispatchMouseEvent() we call EventUtils.synthesizeMouse() on the browser element with the appropriate coordinates but not on the element itself.

To fix that I registered an event listener for mousedown and mouseup on the ownerGlobal, and wrapped that finally inside a Promise. While that code now awaits at least for the event to happen it still returns before the page's onclick event handler has been processed. I wonder if there is a way to further delay it with some option. If that's not possible we might have to identify the specific node at the given position and attach the listener directly.

Comment 2

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Attachment: Bug 1740798 - [puppeteer] Update expected meta data.

Depends on D131211

Comment 3

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Once landed and available in Nightly I'll have to re-enable affected tests upstream. See: https://github.com/puppeteer/puppeteer/issues/7175

Comment 4

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Attachment: Bug 1740798 - [remote] Await the mouse event before returning from Input.dispatchMouseEvent().

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/26d9f747b14f
[remote] Await the mouse event before returning from Input.dispatchMouseEvent(). r=webdriver-reviewers,jdescottes
https://hg.mozilla.org/integration/autoland/rev/aee80b16c695
[puppeteer] Update expected meta data. r=webdriver-reviewers,jdescottes

Comment 6

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/26d9f747b14f
https://hg.mozilla.org/mozilla-central/rev/aee80b16c695

Comment 7

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Looks like I forgot to update the Puppeteer expectation data for the following test:

• Page.click should click the button (click.spec.ts)

I'll add a follow-up patch to this bug on Thursday.

Comment 8

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Attachment: Bug 1740798 - [puppeteer] Remove multiple results from test "Page.click should click the button".

Comment 9

[Henrik Skupin [:whimboo][⌚️UTC+2]]

I've created an upstream PR for re-enabling the tests at: https://github.com/puppeteer/puppeteer/pull/7776

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/20d9468462ff
[puppeteer] Remove multiple results from test "Page.click should click the button". r=webdriver-reviewers,jgraham

Comment 11

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/20d9468462ff

Comment 12

[Henrik Skupin [:whimboo][⌚️UTC+2]]

Upstream PR got merged.