1486483 - Debugger misses sources on first open

Status: RESOLVED DUPLICATE of bug 1503422

(DevTools :: Debugger, defect, P3)

Description

[Yulia Startsev [:yulia]]

STR:
Run debugger-talos test project -> https://github.com/codehag/debugger-talos-example
In a new browser, where devtools has not yet been opened, navigate to localhost:3000
Open the debugger

Expected:
- three folders should be present in the tree:
	debugger-sourcemap/ 
	js/  
	static/

Actual Result:
- Only two folders are present
 	debugger-sourcemap/
	Static/

If you reload the page with the debugger already open, you will see the correct files.

This was found while resolving the talos test to test the lazy source loading work, since we are not loading the JS directory on first load, this might explain why we didn’t see any improvements on first open, and only on reload. Once this is fixed, we will need to update the talos test. The line that should be replaced in the test is this one: `await waitForSource(dbg, expected.sourceURL);` on line 228 in debugger-helper.js. it should be replaced with `await waitForSources(dbg, expected.sources);` which will wait for the full count, rather than just App.js

Comment 1

[Jason Laster [:jlast]]

Arai, is this something you're able to reproduce?

Comment 2

[Tooru Fujisawa [:arai]]

(In reply to Yulia Startsev [:yulia] from comment #0)
> STR:
> Run debugger-talos test project ->
> https://github.com/codehag/debugger-talos-example

how to run?

Comment 3

[Yulia Startsev [:yulia]]

The instructions for running are the same as the create react app: https://github.com/facebook/create-react-app

To quick start:
```
$ yarn
$ yarn start 
```

the full list of commands is in the package.json file. let me know if that works for you!

Comment 4

[Yulia Startsev [:yulia]]

also you can use npm

```
npm install
npm run start
```

Comment 5

[Tooru Fujisawa [:arai]]

thanks :)
yes, I can reproduce

Comment 6

[Brian Hackett [Laid off!]]

I think this is related to the GC.  I'm not able to reproduce this just by loading the page and then opening the debugger, but if I load the page, go to about:memory and click 'Minimize memory usage' (which triggers several GCs/CCs) and *then* open the debugger, the js/ subfolder is missing.  If all the sources in this folder have been collected, the server won't be able to find them and they will not be displayed in the frontend.

Comment 7

[Jason Laster [:jlast]]

> Minimize memory usage

that's a nice trick

Comment 8

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

@Jim: Should this be marked as dup of 1503422? Or what's different in this case?

Honza