Ouch 😢.

I really don't know how to answer this. I appreciate your constructive approach by providing a different approach for #25373. And I really love Symfony! So, if that's the fix for the issue I reported, I'd like to withdraw the bug report 🤕 .

Joking aside: What I don't like about this is that it keeps the (IMO "wrong") regex provided by $compiledRoute->getRegex() as-is to prevent us from twiddling with tests. But then it sneaks in the missing PCRE_DOLLAR_ENDONLY in the right places so the change takes effect?

Don't be sad, you're still the commit author.
The less we need to change tests, the less we potentially break BC.
This fixes the issue totally in practice (your test case is still here.)

Yes, I agree that this probably fixes the issue. And commit authorship is not what I am after ;-)

What I wanted to say is that I love Symfony because of its clean architecture, being mostly free of quirks and ugly fixes. And this change adds the D modifier outside the getRegex method in those places where it matters functionally for the underlying issue, without affecting/breaking/having to change tests that only look at the getRegex return value.

To me, this seems wrong from the software architecture point view :-(.

I don't have the same pov: a Route is a data object, so changing its data description to fix an interpretation issue might not be better. On the architectural pov, nothing changes: the design is exactly the same, interfaces wise. The benefit of this approach is eg that serialized routes will get the fixed behavior too.