1865818 - css files not shown in network when reloading

Status: NEW

(DevTools :: Netmonitor, defect, P3)

Description

[David Balažic]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/119.0

Steps to reproduce:

• open a new private browsing window

• open devtools (F12)

• switch to the Network tab

• paste into URL bar: https://www.iana.org/help/example-domains

• press enter to load the page

• note that a CSS file (iana_website.css) is listed

• clear the network log (trashcan icon)

• reload (by pressing enter in the URL text input or by F5)

• note that now the CSS file is not listed as loaded

Expected results:

the CSS file should be listed (as "cached", like the JS files are).

Comment 1

[David Balažic]

Tested with fresh profile.

Comment 2

[Nicolas Chevobbe [:nchevobbe]]

Thanks for you report, we can reproduce even in non-private windows, as far back as in ESR 115
Looks like we need some specific machinery to list cached stylesheets, as we do for images.

Comment 3

[Alexandre Poirot [:ochameau]]

For images, we register an observer service notification listener to handle cached request:
https://searchfox.org/mozilla-central/rev/d7f837add602d270f2b2958b3ab5206dc85965c0/devtools/server/actors/resources/network-events-content.js#55-58

May be we need something similar for stylesheets based on one of these notifications:
https://searchfox.org/mozilla-central/rev/d7f837add602d270f2b2958b3ab5206dc85965c0/layout/style/Loader.cpp#1580

Comment 4

[Pixievolt No. 1]

The stylesheet does appear in the network log if the page is force-reloaded/shift-reloaded.

Bug 1851349 might be related.