On Wed, Oct 1, 2025, 15:22 Alexandre Daubois <[email protected]>
wrote:

>
> > It boils down to: If you are not confident that you construct the
> pattern in a safe way then what would you do if a validation function
> returns false? You can notify the developer but that is already
> accomplished with the preg_* warning when an invalid pattern is given.
> Creating an error page for the user on a warning is also already possible.
> That's why i'm on the fence whether a validation function does more good or
> harm.
>
> I don't understand how it could be harmful. Early validation is useful
> when it comes to avoiding unnecessary operations if we can already be
> sure that it will fail later for obvious reasons. For me, it falls
> into the same category as email or URL validation in filter_var.
> That's also why I think it would be more appropriate as a flag for
> this function rather than a dedicated function.
>

Emails and URLs are commonly expected end user inputs. Regular expressions
are not, and that is almost always a bad idea.
A bad idea which would be encouraged by making it easy to implement.

I am generally in favor of adding niche functionality, but this one does
worry me.

Cheers,
Andrey.

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