Fastuptodate should check analyzers, rulesets and editorconfigs

[srivatsn]

A build should happen after changing :

• analyzers (Fast up-to-date convert relative path to absolute for item Analyzer in NetCore #6015)
• ruleset files
• .editorconfig files (Fast up-to-date check support for .editorconfig files #4883)

[panopticoncentral]

We already do track analyzer references.

[panopticoncentral]

Rulesets also are tracked as None input items.

[panopticoncentral]

And how do editorconfig file affect the build? Don't just they affect the editor defaults? I don't see them show up anywhere in project files.

[srivatsn]

Rulesets are not none items - they are specified by a codeanalysisruleset property. @jmarolf how are editorconfigs represented in the project?

[panopticoncentral]

Never mind about the ruleset, I got confused by the test scenario I was looking at.
In terms of editorconfig, though, regardless of whether they're represented in the project, how can they affect compilation? I thought they were just editor defaults and aren't part of compilation per-se.

[srivatsn]

There's work being done (not sure of the current state - @jasonmalinowski ?) to pass editorconfig to the compiler so that editorconfig can affect commandline build

[sharwell]

The ability to pass .editorconfig files to the compiler layer is targeted to 15.6. It's well underway but not yet completed. At that point they will be similar to rule set files in their ability to change the impact of analyzers on the build.

[davkean]

Except that worse thing (looking at the last design I saw) is that .editorconfig's don't appear as items in the project. Not sure how we're supposed to be aware of them.

[jasonmalinowski]

dotnet/roslyn#19029 is tracking updating the project systems (both this one and the legacy one) for .editorconfig. And @davkean is correct that we'll have to do a bit of work here.

[panopticoncentral]

@srivatsn Is code analysis working in .NET Core projects? I see #988 about the fact that the UI doesn't work, but when I set a CodeAnalysisRuleSet and turn on code analysis, I get a build error that the platform can't be identified. Wanted to make sure I wasn't doing something wrong, as would need to test this, obviously...

[srivatsn]

FxCop doesn't work but ruleset files affect roslyn analyzers too which works for netcore.

[panopticoncentral]

Original fix cause regressions, see referenced PRs

[Pilchie]

.editorconfig is not in Roslyn yet, and ruleset modifications are rare enough that we can live with this for 15.6

[panopticoncentral]

@drewnoakes I don't think I'm going to get to look at this soon. Is this something you could look at?

[drewnoakes]

Sure, I'll pick it up.