CheckMojo: introduce failThreshold

[famod]

Resolves #219

Notes:

• First I cleaned up the duplicate parsing of outputFile and the scoping of bugCount and errorCount (see first commit)
• The recent Groovy update from 3.0.3 to 3.0.4 kills your builds: https://travis-ci.org/github/spotbugs/spotbugs-maven-plugin/builds/690024559

  [ERROR] Failed to execute goal org.apache.maven.plugins:maven-invoker-plugin:3.2.1:install (prepare-integration-test) on project spotbugs-maven-plugin: Execution prepare-integration-test of goal org.apache.maven.plugins:maven-invoker-plugin:3.2.1:install failed: Plugin org.apache.maven.plugins:maven-invoker-plugin:3.2.1 or one of its dependencies could not be resolved: Could not find artifact org.testng:testng:jar:7.2.0 in google-maven-central (https://maven-central.storage-download.googleapis.com/maven2/) -> [Help 1]
  

  I get the same error locally which is why this change is not in my PR branch (based on 689c796 instead). (see first comment)
• This PR also adds a priority prefix to the log message:
  Before:

  [ERROR] Overwritten increment in UselessAssignments.oops() [UselessAssignments] At UselessAssignments.java:[line 30] DLS_OVERWRITTEN_INCREMENT
  

  With this PR:

  [ERROR] High: Overwritten increment in UselessAssignments.oops() [UselessAssignments] At UselessAssignments.java:[line 30] DLS_OVERWRITTEN_INCREMENT
  

[famod]

I just realized that your Travis build uses the latest commits anyway so I rebased my branch.
This will (of course) fail all the builds for this PR until the TestNG problem is fixed.

[famod]

@hazendaz WDYT?

[hazendaz]

travis ci is dicey these days. I tried to rebuild this yesterday but no luck. Issue was not groovy but rather the invoker pulling testng. I don't see us using testng but it's having issues getting it. I tried running it again tonight. I'd like to see travis successful. I also need to wrap my head around the changes a bit more. A quick look seems ok but just want to review some of the naming changes and make sure it looks appropriate for current usage. So I'm on board with it just need to get travis working and look at it in a little more depth. I'll try to get to it in next couple of days. If travis continues to fail, can you take a look at what might be causing that? I'm pretty sure when I upgraded groovy it was fine on that pull request. I usually skip merging if travis is having issues unless its related to pulling a lib it cannot find. That could have been the case on the groovy update. I don't recall off hand.

[famod]

@hazendaz

Well, the Groovy upgrade PR ran into the same problem: #221
I can reproduce it locally, so this is not a Travis problem, AFAICS.

[hazendaz]

@famod Thanks. I'll take a look tonight.

[famod]

@hazendaz friendly reminder! 🙂

[hazendaz]

I need to ping testng folks I think to get them to release their binary. Their github states it was released but obviously wans't in central last I checked. I kicked off another build just now. If it fails again, I'll reach out to that team.

[famod]

So it failed again.

IMHO, the groovy update should be rolled back for now.

[hazendaz]

@famod Rebuilding now. Issue fixed. We don't use testng but the groovy plugin uses groovy all which we override to latest. Per groovy, they messed up by using testng on version not released to central, testng has since removed notice of testng release. Since we don't use testng, I followed groovy's work around to exclude it from the groovy plugin and builds are back to normal. As soon as this goes green, I'll review once again and then get it merged.

[hazendaz]

@famod Thank you! Merging now.

[famod]

@hazendaz Awesome, thanks! Any plans on cutting a new release?

[hazendaz]

@famod I'm waiting on a pull request to be corrected so the test for htm vs xml works. I'd like to include that. So hopefully soon. If I don't hear anything back this coming week on the other pull request, I'll likely just move fowards without it.

[famod]

Thanks for your feedback!

[famod]

@hazendaz Any news regarding a new release? Thanks!

[hazendaz]

@famod I'll release this tonight.

[hazendaz]

@famod Released, it will be available in central in next 2 hours or so. You should be able to otherwise pull it probably in about 15 minutes or so.

[hazendaz]

Version 4.0.4 to match line of spotbugs.

[famod]

@hazendaz Great, thanks!