Actions should register problem matchers for errors and warnings

[chrispat]

Please see the actions/setup-dotnet repo as an example.

https://github.com/actions/setup-dotnet/blob/master/src/setup-dotnet.ts#L30
https://github.com/actions/setup-dotnet/blob/master/.github/csc.json

[timheuer]

@chrispat is there more documentation on what this is, where it surfaces, why it is important?

[chrispat]

The problem matcher will automatically surface as annotations on the pull request and other files so you could easily see where compiler errors or warnings are. The design is essentially the same as VSCode which uses them to give you errors and warnings in the editor rather than having to dig through the text log.

[timheuer]

Are there docs on this. I see the repo you pointed to but not sure if I directly copy that or how can I learn more about the json files and relationships. Totally up to do this. Guide me?

[chrispat]

Sure here are the docs https://github.com/actions/toolkit/blob/master/docs/problem-matchers.md

[reupen]

I tried using a problem matcher in one of my repos, but I abandoned it as it didn't handle message for a single error or warning that spanned multiple lines, and was also generally a pain for various reasons.

I'm now using a custom logger which is a much more flexible solution. I've published the one I created here:
https://github.com/reupen/msbuild-github-logger

I've also dumped the abandoned problem matcher here in case it's of use to anyone (it is possible to register a problem matcher from your own workflow for reference):

https://gist.github.com/reupen/f2320e353554f4fa4d3693fd38c850d4