1625961 - Use the ResourceWatcher API to fetch Root NodeFront

Status: RESOLVED FIXED

(DevTools :: Inspector, task, P2)

Description

[Alexandre Poirot [:ochameau]]

Bug 157662 introduced the ResourceWatcher API, accessible via toolbox.resourceWatcher. This API will help listen to data that is being created early, when the document just started loading.

We should migrate the whole DevTools codebase to this API for any data that:

• DevTools frontend listen to, or care about,
  and,
• may be created or be notified early, when the document just starts being loaded.
  This data will typically be: console messages, errors, warnings, sources, Root element NodeFront, storage values, network events, stylesheets, ...

We are typically not going to use this API for:

• data being fetched on-demand, from user's input. For ex: webconsole evaluation input, or, DOM element expands from the Markup view.
• events which we only want to record when the user cares about them. For ex: animation events.

For some more high level context, please have a look at Migration to Fission-compatible APIs, which describes all Fission-related refactorings.

The typical task for this bug will be about migrating code that:

• start listening and register a RDP event listener,
• retrieve already existings data,
  from panel's codebase, to the ResourceWatcher module, in the LegacyListener object.
  And then, the panel should use the ResourceWatcher instead.

Bug 1620234 is a good example of such migration, applied to Console Messages.
Bug 1623699 is also useful example as it demonstrates how to write tests for such migration.

This bug is about focusing on only one usecase: the root DOM Element NodeFront.

This work depends on bug 1611096, which make the root NodeFront retrieval closer to a what we need here.

Before this work, the root NodeFront was emited via the Walker actor mutations event, from here:
https://searchfox.org/mozilla-central/source/devtools/server/actors/inspector/walker.js#2511-2514
or, retrieved on initialization or the walker actor from here:
https://searchfox.org/mozilla-central/source/devtools/server/actors/inspector/walker.js#377-387

After this work a new new-root-available event is fired on the Walker actor and I think we rely on the same code for initialization.

Comment 1

[Chris Peterson [:cpeterson]]

Tracking Fission DevTools bugs for Fission Nightly (M6) milestone

Comment 2

[Julian Descottes [:jdescottes]]

Attachment: Bug 1625961 - Use the ResourceWatcher API to fetch Root NodeFront

Depends on D62625

Comment 3

[Julian Descottes [:jdescottes]]

Attachment: Bug 1625961 - Throw when calling ResourceWatcher::watch twice for the same type

Depends on D72668

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/18646e7b984f
Use the ResourceWatcher API to fetch Root NodeFront r=ochameau,nchevobbe
https://hg.mozilla.org/integration/autoland/rev/977b0031b41c
Throw when calling ResourceWatcher::watch twice for the same type r=nchevobbe,ochameau

Comment 5

[Dorel Luca [:dluca]]

Backed out 3 changesets (bug 1635467, bug 1625961) for Devtools failures in resources/tests/browser_resources_exceptions.js. CLOSED TREE

Log:
https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=301557137&repo=autoland&lineNumber=14173

Push with failure:
https://treeherder.mozilla.org/#/jobs?repo=autoland&group_state=expanded&revision=1fd6a3754afb1497c1169d7054f5466e38b197a4

Backout:
https://hg.mozilla.org/integration/autoland/rev/494916b74ee5b90dc116b5f84c8f9a8c34c97624

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c7757cea8327
Use the ResourceWatcher API to fetch Root NodeFront r=ochameau,nchevobbe
https://hg.mozilla.org/integration/autoland/rev/cf46002eefb0
Throw when calling ResourceWatcher::watch twice for the same type r=nchevobbe,ochameau

Comment 7

[Razvan Maries]

Backed out for mochitest perma failures.

See https://bugzilla.mozilla.org/show_bug.cgi?id=1635467#c6

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c24dddd0d636
Use the ResourceWatcher API to fetch Root NodeFront r=ochameau,nchevobbe
https://hg.mozilla.org/integration/autoland/rev/ec4126b8bd7a
Throw when calling ResourceWatcher::watch twice for the same type r=nchevobbe,ochameau

Comment 9

[Cristian Brindusan [:cbrindusan]]

https://hg.mozilla.org/mozilla-central/rev/c24dddd0d636
https://hg.mozilla.org/mozilla-central/rev/ec4126b8bd7a