RegexRouteConstraint should use Compiled Regex

[eerhardt]

Today, when using a regex route constraint, we create a new Regex:

aspnetcore/src/Http/Routing/src/Constraints/RegexRouteConstraint.cs

Lines 40 to 43 in e523876

	Constraint = new Regex(
	regexPattern,
	RegexOptions.CultureInvariant | RegexOptions.IgnoreCase,
	RegexMatchTimeout);

This should use the RegexOptions.Compiled as well. That way we aren't interpreting these regular expressions every time the route is inspected.

Our docs even say this should be using Compiled:

The ASP.NET Core framework adds RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.CultureInvariant to the regular expression constructor. See RegexOptions for a description of these members.

Thanks for contacting us.

We're moving this issue to the .NET 8 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.