Bug 290256 – DeclarativeNetRequest rules are not applied to a new default profile window in some circumstances

• Status: NEW
• Component: WebKit Extensions

[Jeff Johnson]

Created attachment 474686 [details]
Sample Xcode project

Safari 18.3.1 on macOS 15.3.2

With multiple Safari profiles, DeclarativeNetRequest rules are not applied to a new window in some circumstances.

Steps to reproduce:
1) In Safari Profiles Settings, create a profile, for example "Test"
2) Unzip, build, run, and enable the attached Safari extension DNRProfilesBug
3) Verify with https://gs.statcounter.com/detect that a custom User-Agent is set in both Personal and Test profiles
4) Close all Safari windows
5) Open a Test profile window
6) Quit Safari
7) Open Safari (which should open with a Test profile window)
8) New Personal Window
9) Open https://gs.statcounter.com/detect in the new Personal window

Expected results: User-Agent "none"

Actual results: User-Agent "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.3.1 Safari/605.1.15"

You can open the extension popup window to verify that the DeclarativeNetRequest rules are still set to customize the User-Agent, even though the rules aren't currently effective in the tab.

Note that the bug does not occur if the profiles are reversed, i.e., if Safari opens with a Personal profile window, and you open a New Test Window.

[Radar WebKit Bug Importer]

<rdar://problem/147651045>