User should be able to decide whether or not to see sonar rules as warning during build

[Evangelink]

Description

Currently, when using the Scanner for MSBuild, the user will see all .net issues from any sonar rule (SonarC#, SonarVB, any plugin created via the SonarQube Roslyn SDK) raised as warnings during the build.

Some of our users think that this is too noisy. They want to focus on regular warnings and use SonarQube/SonarCloud for sonar-related issues.

Expected behavior

The user should be able to select between having sonar issues raised as warning or message during the build.

Known workarounds

After the begin step is run, the user can update the ruleset located at .sonarqube\conf\***.ruleset and replace all Action="Warning" with Action="Info".

Suggested solution

We could provide a new parameter available that can be passed to the begin step so that the sonar-related issues are raised as Message during the build and not as Warning.

Note that there is no need for the user to be able to specify Error (as it will result in a broken build) nor Hidden (as this prevent issues to be reported in the roslyn json file).

[AndersLindPedersen]

What is status on this. We are one of that teams that would like to focus on the regular build warnings

[duncanp-lseg]

This came up in the community again recently: https://community.sonarsource.com/t/c-do-not-display-the-found-violations-as-a-warning-in-the-compiler/61459

@tom-howlett-sonarsource, what do you think?