1588741 - Descriptors.getTarget races when called in parallel

Status: RESOLVED FIXED

(DevTools :: Framework, defect, P2)

Description

[Alexandre Poirot [:ochameau]]

When calling FrameDescriptor.getTarget or ProcessDescriptor.getTarget concurrently, you may have access to a target that is still in process of attaching:
https://searchfox.org/mozilla-central/rev/17756e2a5c180d980a4b08d99f8cc0c97290ae8d/devtools/shared/fronts/descriptors/frame.js#59-60

    if (this._frameTargetFront && this._frameTargetFront.actorID) {
      return this._frameTargetFront; /// <<=== here we may return the unattached target
    }
    if (this._targetFrontPromise) {
      return this._targetFrontPromise;
    }
    this._targetFrontPromise = (async () => {
        ...
        this._frameTargetFront = await this._createFrameTarget(targetForm); // <== here we save the unattached target
        await this._frameTargetFront.attach();

The same pattern is used for processes:
https://searchfox.org/mozilla-central/source/devtools/shared/fronts/descriptors/process.js#66

Comment 1

[Alexandre Poirot [:ochameau]]

Attachment: Bug 1588741 - Descriptors.getTarget may return unattached targets when called in parallel.

Comment 2

[Alexandre Poirot [:ochameau]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=28599c2dcd3b5fcc4554363dd3d59b0457b6e236
(the try run includes bug 1471754, which introduces failures)

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4f546e70e68e
Descriptors.getTarget may return unattached targets when called in parallel. r=jdescottes

Comment 4

[Bogdan Tara[:bogdan_tara | bogdant]]

https://hg.mozilla.org/mozilla-central/rev/4f546e70e68e