Bugfix FXIOS-9699 [webcompat] Force mobile UA for PayPal

[janbrasna]

📜 Tickets

Jira tickets: FXIOS-8027 (FXIOS-11230), FXIOS-9699
Github issues: #17911 (#24431), #21314

💡 Description

This moves the UAstring override for PayPal.com from the mobile section (where it defaults to the default anyways) to the desktop section, which correlates with the default setting for iPads; where most of the issues occur.

(Also: removes the default for yahoo.com, that also sends just default…)

NB: This is not a real fix of the underlying issue #17911 (comment) (as PayPal explicitly states that it should not be used from within WebViews, so whenever they insist on opening a popup the bug would demonstrate again) — this is just signaling them a mobile device, to open the widget in the same frame/tab, thus avoiding the about:blank breakage.

(In other words, getting desktop mode behavior for PayPal checkout buttons on par with with mobile mode, where issues are not being reported, for consistency.)

📝 Checklist

You have to check all boxes before merging

• Filled in the above information (tickets numbers and description of your work)
• Updated the PR name to follow our PR naming guidelines
• Wrote unit tests and/or ensured the tests suite is passing
• If needed, added a backport comment (example @Mergifyio backport release/v120)

[yoanarios]

Hello @janbrasna thank you for opening this PR. I'm investigating Paypal bugs and I've tried a similar solution adding "paypal.com" to customDesktopUAForDomain but while testing I found that works only the first time if we close the popup and press Paypal button again it returns to desktopUA behaviour opening a blank page.

I've tested your changes and I'm seeing the same behaviour I will attach a video, although this is an edge case (closing the PopUp and press the button again) I think it will be best to have a solution that works every time

Simulator.Screen.Recording.-.iPad.Pro.11-inch.M4.-.2025-02-03.at.10.38.20.mp4

[janbrasna]

👋 Thanks @yoanarios — I will have to introspect their popup code a bit more in that case, to understand what they are trying to do, and how comes the handler changes like this 👀 — that would seem to actually get the desktop UA string from JS navigator object of the original merchant site, not just their scripts requested, but haven't really debugged their code what changes based on the user agent, TBD…

(I would never consider this to be a real fix, just wanted to improve the situation a little bit for now… as the UAstring overrides in their current form made no difference, this at least tries… ;D)

[yoanarios]

👋 Thanks @yoanarios — I will have to introspect their popup code a bit more in that case, to understand what they are trying to do, and how comes the handler changes like this 👀 — that would seem to actually get the desktop UA string from JS navigator object of the original merchant site, not just their scripts requested, but haven't really debugged their code what changes based on the user agent, TBD…

(I would never consider this to be a real fix, just wanted to improve the situation a little bit for now… as the UAstring overrides in their current form made no difference, this at least tries… ;D)

That makes sense! Since this improves the flow, we can merge it. Meanwhile, I will continue working on fully resolving the blank page issue when the user closes the popup. Thanks for pushing this forward! 🚀

[yoanarios]

@Mergifyio backport release/v136

[mergify]

backport release/v136

✅ Backports have been created

• #24637 Bugfix FXIOS-9699 [webcompat] Force mobile UA for PayPal (backport #24497) has been created for branch release/v136