1742107 - Can't click on buttons of paused overlay in an iframe when EFT is enabled and Fission is disabled

Status: RESOLVED FIXED

(DevTools :: Debugger, defect)

Description

[Nicolas Chevobbe [:nchevobbe]]

Steps to reproduce

1. With EFT enabled and Fission disabled
2. Open a tab with data:text/html,<meta charset=utf8><h1>Top</h1><iframe src="data:text/html,<script>document.addEventListener(click, () => { debugger; })</script><h2>Iframe</iframe>"></iframe>
3. Open devtools
4. Click on the Iframe text
5. The paused overlay should be shown, inside the iframe
6. Click on the ▶️ button to resume

Expected results

The debugger resumes and the overlay is hidden

Actual results

Nothing happens

---

The handleEvent method of PausedDebuggerOverlay is not called, but it should.
Looking in C++ code, I found out that the setSuppressedEventListener (https://searchfox.org/mozilla-central/rev/0f3e259c24e52932387318ac503bfad3c82baa44/devtools/server/actors/highlighters/paused-debugger.js#239) we use to get the mouse events while the document is paused doesn't seem to have any effect.
The event should be dispatched from https://searchfox.org/mozilla-central/rev/0f3e259c24e52932387318ac503bfad3c82baa44/layout/base/PresShell.cpp#7704 , but it is blocked at an early line (https://searchfox.org/mozilla-central/rev/0f3e259c24e52932387318ac503bfad3c82baa44/layout/base/PresShell.cpp#7656-7660)
And indeed, if in the highlighter show method I add this.env.window.windowUtils.suppressEventHandling(true); , I do receive the mouse events, and I can resume the page, and hide the overlay.

suppressEventHandling(true) is supposed to be called from https://searchfox.org/mozilla-central/rev/0f3e259c24e52932387318ac503bfad3c82baa44/devtools/server/actors/utils/event-loop.js#191 , but it's not

Comment 1

[Nicolas Chevobbe [:nchevobbe]]

We're actively filtering out same origin iframes in getAllWindowDebuggees (https://searchfox.org/mozilla-central/rev/0f3e259c24e52932387318ac503bfad3c82baa44/devtools/server/actors/utils/event-loop.js#169-171), so with EFT, we don't get the window, and never call suppressEventHandling on it.

Comment 2

[Nicolas Chevobbe [:nchevobbe]]

Attachment: Bug 1742107 - [devtools] Don't ignore same-origin iframe in EventLoop#getAllDebuggees. r=bomsy.

This was causing some issues with PausedDebuggerOverlay with EFT:
As we weren't returning the window to preEnter, we weren't calling
suppressEventHandling on it, which in the end made the call we
have in the overlay to setSuppressedEventListener inoperant.
This wasn't caught by the browser_dbg-paused-overlay-iframe.js test
we have as the method we use to simulate clicking on the button
(highlighterTestFront.clickPausedDebuggerOverlayButton), ends ups calling
the handleEvent method of the highlighter actor directly, bypassing the
regular flow of events in a paused page.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/31fca3976f3b
[devtools] Don't ignore same-origin iframe in EventLoop#getAllDebuggees. r=bomsy.

Comment 4

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/31fca3976f3b

Comment 5

[Chris Peterson [:cpeterson]]

Setting status-firefox95=wontfix. I assume we don't need to uplift this fix to Beta 95 because EFT is only enabled in Nightly