Regex pattern replacement fails if destination is absolute url.

[earthlingdavey]

Describe the bug

When using regex pattern replacement, using $1 doesn't work as expected when the destination is an absolute url.

Steps to Reproduce

1. Create a redirect with source /test/(.*)
2. Enable Regular Expressions true
3. Redirect to https://google.com/$1
4. Visit /test/abc Expected destination is https://google.com/abc actual destination is https://google.com/1

Screenshots, screen recording, code snippet

NA

Environment information

NA

WordPress information

NA

Code of Conduct

• [X] I agree to follow this project's Code of Conduct

[guillaumemolter]

I can confirm this bug

[benlk]

I confirm this bug as well.

I think the error is here but will need to test next week:

https://github.com/10up/safe-redirect-manager/blob/cb1c04513b75736a0938208c5837b3ce51abdcba/inc/classes/class-srm-redirect.php#L225-L229

[benlk]

Using the example redirect:

from: /test/(.*)
to: https://example.org/$1
regex: true

https://github.com/10up/safe-redirect-manager/blob/cb1c04513b75736a0938208c5837b3ce51abdcba/inc/classes/class-srm-redirect.php#L225-L229

filter_var( $redirect_to, FILTER_VALIDATE_URL ) returns https://example.org/$1

! filter_var( $redirect_to, FILTER_VALIDATE_URL ) returns the Boolean opposite of a string, which since strings are truthy is false