1638482 - Intermittently can't set breakpoint at top-level of <script type="module">, only inside functions

Status: RESOLVED DUPLICATE of bug 1605686

(DevTools :: Debugger, defect)

Description

[Matthew N. [:MattN]]

Attachment: Actual result image

What were you doing?

Prerequisite to help reproduce: Have no existing breakpoints and no debugger tabs open.

1. Open about:logins
2. Open the devtools debugger (regular webdev debugger)
3. Hit Comannd-P to Go to File (not sure of the shortcut on macOS but you can also click "Go to file"
4. type aboutLogins.js (or some prefix)
5. Choose aboutLogins.js

Closing the debugger tabs, removing all breakpoints, closing the toolbox, then reloading the tab will help to reproduce the problem.

What happened?

I'm not able to set breakpoints on lines at the top-level of the module. The line numbers are grey indicating it's disabled and clicking doesn't work.

What should have happened?

I should be able to set breakpoints on code executing in the top-level of the module.

Anything else we should know?

I tried to find a regression range but then learned that the issue was intermittent.

This happens for

<script type="module" src="chrome://browser/content/aboutlogins/aboutLogins.js"></script>

but I don't know if the bug is module-specific or not.

Do you have extensions installed? No, this happened in a new profile.

Comment 1

[Matthew N. [:MattN]]

Attachment: Expect result image

I got the correct behaviour by simply reloading the tab with the toolbox still open right after taking the actual result screenshot.