1625026 - Remove workaround for about:blank document from FrameWatchers.jsm

Status: RESOLVED FIXED

(DevTools :: Framework, enhancement, P2)

Description

[Alexandre Poirot [:ochameau]]

Bug 1593937 introduces a workaround for about:blank documents preloaded in browser elements. If we do create targets for these about:blank loads, we end up with broken targets as these documents loads are specials. We should try to ignore them, especially or figure out why the targets are broken.

Comment 1

[Chris Peterson [:cpeterson]]

Tracking Fission DevTools bugs for Fission Nightly (M6) milestone

Comment 2

[Chris Peterson [:cpeterson]]

Tracking dt-fission-m2-mvp bugs for Fission Nightly milestone (M6c)

Comment 3

[Neha Kochar [:neha]]

Bulk move of all dt-fission-m3-mvp bugs to Fission MVP milestone.

Comment 4

[Alexandre Poirot [:ochameau]]

There is now two callsites where we ignore about:blank documents, and the second became more complex because of print preview:
https://searchfox.org/mozilla-central/rev/dac45cc7020dfddbcc937827810dd11550c07dc3/devtools/server/actors/watcher/target-helpers/utils.js#41-48
https://searchfox.org/mozilla-central/rev/dac45cc7020dfddbcc937827810dd11550c07dc3/devtools/server/connectors/js-window-actor/DevToolsFrameChild.jsm#39-62

Keeping this workaround may prevent us from correctly opening the tools against empty documents. Opening DevTools against about:blank, or inspecting remote iframes loading about:blank. This may become a bigger issue once we want to address bug 1686748.
Removing this workaround break tests (last time I tried), and can probably become a performance issue.

Comment 5

[Chris Peterson [:cpeterson]]

Moving some dt-fission-m3-mvp bugs from Fission MVP to M7 (blocking Beta experiment).

Comment 6

[Chris Peterson [:cpeterson]]

Tracking dt-fission-m3-mvp test and infrastructure bugs for Fission M8 (blocking Release experiment).

Comment 7

[Chris Peterson [:cpeterson]]

Tracking DevTools Post-M8 bugs for Fission MVP milestone. They don't block the Fission Release channel experiment, but we would like them to be completed before we roll out Fission by default.

Comment 8

[Alexandre Poirot [:ochameau]]

This ends up being an issue for enabling server side targets (bug 1698891). With this code ignoring about:blank documents, we do break support for debugging tabs opened against about:blank. A few tests break because of that.

Having said that, Nika started investigating removing the transcient about:blank document created when navigating to another process.
That was the one transcient document we tried to workaround.
If this platform work happens, this would probably fix this and we will be able to remove this code.

If this platform tweak doesn't happen soon enough, we would have to either:

• tune the about:blank checks to ignore only the transcient documents,
• generate targets for these transcient document and make it so that the frontend doesn't crash because of multiple target swiches being done in a row.

Comment 9

[Alexandre Poirot [:ochameau]]

Attachment: Bug 1625026 - [devtools] Accept about:blank documents in frame target helpers.

The check in DevToolsFrameChild was wrong with the browser toolbox codepath.
We don't have any browserId. This wasn't throwing because shouldNotifyWindowGlobal
was rejecting the about:blank documents.
This issue was catched by browser_console_content_object_in_sidebar.js,
which probably only involve about:blank documents.

Comment 10

[Alexandre Poirot [:ochameau]]

Attachment: Bug 1625026 - [devtools] Accept final about:blank documents in DevToolsFrameChild.

This helps create targets in the browser toolbox for tabs loaded directly against about:blank.

Comment 11

[Alexandre Poirot [:ochameau]]

Attachment: Bug 1625026 - Listen to DOMDocElementInserted and log all events

Comment 12

[Nika Layzell [:nika] (ni? for response)]

Attachment: Bug 1625026 - Add a flag to track whether the window global was created as a temporary about:blank for process switches

Comment 13

[Alexandre Poirot [:ochameau]]

Attachment: Bug 1625026 - Implements WindowContext.isInitialAboutBlankCreatedByProcessSwitch.

This attribute will be true when the WindowContext is related
to the transient about:blank document created while navigation to another process.
This helps identify this transient document and better identify the actual
to-be-loaded-right-after document.

Comment 14

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1e05e9f5f957
[devtools] Accept about:blank documents in frame target helpers. r=jdescottes
https://hg.mozilla.org/integration/autoland/rev/cdc308875d98
[devtools] Accept final about:blank documents in DevToolsFrameChild. r=jdescottes

Comment 15

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/1e05e9f5f957
https://hg.mozilla.org/mozilla-central/rev/cdc308875d98