1539294 - Extensions can cause XHR Breakpoint pauses in index file, not on the right fetch

Status: RESOLVED DUPLICATE of bug 1548707

(DevTools :: Debugger, defect, P3)

Description

[:Harald Kirschner :digitarald]

Attachment: image.png

What were you doing?

1. Open Debugger on https://panoramic-kitty.glitch.me/
2. Enable to pause on XHR
3. Wait for pausing

What happened?

Pauses on fetch in index.js

What should have happened?

Pauses on first line in index.html

Comment 1

[:Harald Kirschner :digitarald]

Logan, I am not sure if I have seen this working correctly before. Is the backend providing enough information to pause in index.js?

Comment 2

[Jan Honza Odvarko [:Honza] (always need-info? me)]

Attachment: image.png

I am not sure if it behaves the same for me.

The execution pauses in client.js, line 7 on my machine.

Honza

Comment 3

[Logan Smyth [:loganfsmyth]]

I'm also not able to reproduce this on Nightly, but it does happen to me on 66. Perhaps this is something we fixed with Brian's source work?

Comment 4

[:Harald Kirschner :digitarald]

This is probably an extension that overrides the fetch behavior, as I can see the minified fetch inspected in the scope. Trying to see which extension this would be …

Comment 5

[Jan Honza Odvarko [:Honza] (always need-info? me)]

Harald, can you point me to an extension that you think caused the problem? I can test it. Currently, I am still seeing the same, the execution pauses in client.js, line 7 on my machine - there is no issue.

Or we might want to close this one.

Honza

Comment 6

[:Harald Kirschner :digitarald]

Confirmed that the extension causing this is LastPass, which overrides fetch in its content script.

Comment 7

[Logan Smyth [:loganfsmyth]]

Perfect. I think this is a duplicate of https://bugzilla.mozilla.org/show_bug.cgi?id=1548707 It just shouldn't be showing that HTML file in the first place. It should show you the extension script, or not pause.