[PiranhaJava] Update sample project to show option for excluding additional EP checks

[sivacoder]

In the past we have made PR's to Piranha to support additional usage patterns.

While integrating Piranha with multiple java micro services in our organisation, we are noticing lots of Error prone reported violations on our micro-service project and it becomes a hard dependency to fix the violations before integrating Piranha.

For new projects, we can add Error Prone as a dependency from beginning and get going. But for existing services, fixing the error prone violations is becoming hard.

Question:

1. is it possible to run Piranha without Error Prone as a mandatory dependency in build system?
2. If not, is it possible to suppress the Error Prone violation as warning instead of build errors?
3. iI it possible to exclude specific packages from Error Prone scan? (Like available configurations available in Jacoco/find bug and so on)

[mkr-plse]

You should be able to -XepDisableAllChecks and then just enable Piranha check to avoid EP violations. Similarly,
-XepExcludedPaths can be used to exclude certain paths from analysis. See errorprone documentation for more details.

Useful to update the sample project with all EP checks disabled.

[lazaroclapp]

Keep in mind that -XepExcludedPaths will also exclude everything from being processed by Piranha.

-XepDisableAllChecks is what you most likely want, if you are not otherwise using Error Prone, followed by the Piranha specific configuration.

Action item: Let's figure out if we can modify the sample project and README configuration such that it will disable all checks if and only if the build is not already using Error Prone. Otherwise, this might require providing two separate configuration templates.

[sivacoder]

Thanks @lazaroclapp @mkr-plse for the awesome support. We tested with -XepDisableAllChecks and works like charm. Thanks a ton.

[mkr-plse]

@sivacoder Good to know that it worked for you :)
Reopening this issue until the sample project is updated to show this option.