User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0

Steps to reproduce:

• Go to http://vosteran.com
• Open inspector
• Click the '+' icon next to 'Filter Styles'

Actual results:

• An empty <style> tag is added just before the closing html tag.
• The rule does not appear in the rules panel
• An error is logged: Content Security Policy: The page’s settings blocked the loading of a resource at inline (“default-src”).

Expected results:

The rule should be created

Thanks for the report, I couldn't reproduce on the website mentioned in the summary, but the test page from Bug 1228985 shows the issue:

https://bug1228985.bmoattachments.org/attachment.cgi?id=9149557

STRs:

• open https://bug1228985.bmoattachments.org/attachment.cgi?id=9149557
• open DevTools > Inspector
• click on + in the Rule View

ER:
A new rule should be created.

AR:
No new rule created.

The oldest Firefox version that I manged to run without crashing (92) already had this bug. So probably not a recent regression.

I was able to reproduce this issue and get a regression range but it seems our tool couldnt bisect more builds and this is the best we could do:

7:48.44 INFO: Last good revision: 2da6d806f45732e169fd8e7ea9a9761fa7fed93d (2021-03-25)
7:48.44 INFO: First bad revision: 55c63a6c547f1fecd412505a064f21fd1e1ec48e (2021-03-26)
7:48.44 INFO: Pushlog:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=2da6d806f45732e169fd8e7ea9a9761fa7fed93d&tochange=55c63a6c547f1fecd412505a064f21fd1e1ec48e

Hopefully one of our devs can take a look and might identify what is causing this.

Great work. I am pretty sure this was caused by "Bug 1685268 - Enable STYLESHEET resource type by default". Looking at the code here: https://searchfox.org/mozilla-central/source/devtools/server/actors/page-style.js#1162-1177 We can see that getStyleElement is never called, which contains the code added Bug 1228985 to fix this bug.

Thanks for the regression window and for the investigation! We still have 2 codepaths for stylesheet management, but we should soon only have one.

Let's fix the regression and add a test.

https://hg.mozilla.org/mozilla-central/rev/80167c80abe4

Verified as fixed in our latest build 109.0a1 (2022-11-14).

The patch landed in nightly and beta is affected.
:jdescottes, is this bug important enough to require an uplift?

• If yes, please nominate the patch for beta approval.
• If no, please set status-firefox108 to wontfix.

For more information, please visit auto_nag documentation.

Not a recent regression, this can ride the trains.

Updating the remaining flag.