Improvement: Upgrade error-prone to 2.4.0

[robert3005]

Before this PR

We are using error-prone 2.3.4

After this PR

https://github.com/google/error-prone/releases/tag/v2.4.0
==COMMIT_MSG==
Upgarde error-prone to 2.4.0 to support latest jdks
==COMMIT_MSG==

Possible downsides?

There's 300 commits in the diff, surely there are bunch of checks that need autofixes applied

[ferozco]

Lets try this out on a few repos before letting it rip more widely

[robert3005]

We also should remove our jdk 12, 13 overrides as they shouldn't be necessary

[carterkozak]

Many MoreASTHelpers/MoreSuggestedFixes methods are no longer necessary since our fixes were merged upstream.

[robert3005]

Cool, will fix those as well. Also found that your JavaTime check bug was fixed so we can reenable that

[robert3005]

@carterkozak couldn't find things in MoreAstHelpers that could be removed - have specific methods/bugs in mind? Found some

[robert3005]

I found some cases of JdkObsolete check complaining about types from libraries, i.e. right now it doesn't like SortedMap that dropwizard-metrics uses.

[ferozco]

We should also clean up some of the work arounds in the gradle plugin itself. ex:

gradle-baseline/gradle-baseline-java/src/main/groovy/com/palantir/baseline/plugins/BaselineErrorProne.java

Line 227 in a927d38

if (jdkVersion.compareTo(JavaVersion.toVersion("12.0.1")) >= 0) {

[robert3005]

@ferozco I have removed it already

[ferozco]

👍

[pkoenig10]

FYI these commits in error-prone 2.4.0 are going to cause a lot of failures for common nested imports.
https://github.com/google/error-prone/blame/7037696f4b00c8137394b10d143e37072b6048f6/core/src/main/java/com/google/errorprone/bugpatterns/BadImport.java#L63-L71

[carterkozak]

Would you mind trying the automated fixes and reporting back? If they seem safe and sane we can apply them automatically.

[pkoenig10]

The suggested fixes seemed to work pretty well, let's apply them automatically.
#1387

[pkoenig10]

I also ran into a bunch of issues with JdkObsolete because it matches any use of methods on obsolete classes, even if you're just using an obsolete type returned from a library or passing an obsolete type to a library.

This was due to this change:
google/error-prone@6671c25#diff-065165cb9efc7cfdb26debe40d8ea8ccR230-R245

[ferozco]

I would be in favour of disabling the rule. I think its pretty lame to get warnings for code you don't control

[pkoenig10]

Looks like this is being tracked in google/error-prone#1646