Regex.IsMatch(string, string) inside NamingSettings.ctor is causing 15.1% allocations

[ninedan]

Building a large project, found Regex.IsMatch(string, string) inside NamingSettings.ctor is causing 15.1% allocations, mostly due to constructing regular expression repeatitively. At least the regular expressions should be reused.

[MartyIX]

How do you actually measure this please? I would love to measure impact of an analyzer of mine but I'm not sure how to do it.

[ninedan]

Building a large .cs project, capturing a trace using PerfView. This stack is bad enough that any trace invoking it will show.

[bjornhellander]

My understanding was that Regex.IsMatch caches the instance, but maybe the cache isn't big enough for everything needed while compiling a large solution.

I am having problems actually measuring this, but changing to having a static field with the Regex instead of calling Regex.IsMatch seems trivial. Do you see any downsides to that, @sharwell?

Or maybe rewrite to not use a Regex at all, since the pattern is so simple?