Add null safety for any use of ReaderSource.getURI()

[AntonPanikov]

Task List

• Steps to reproduce provided
• Stacktrace (if present) provided
• Example that reproduces the problem uploaded to Github
• Full description of the issue provided (see below)

Environment Information

• Grails Version: 3.2.x

I am helping troubleshooting GRECLIPSE plugin issue: groovy/groovy-eclipse#850

It looks like MainClassFinder.groovy is not null safe enough. URI path is coming from ReaderSource.java
from
IntegrationTestMixinTransformation.groovy

and for example this two implementations of ReaderSource:
StringReaderSource.java
and
InputStreamReaderSource.java
is returning null, the first one at some conditions, the second one - always.

Missing null safety causing NPE in GRECLIPSE current implementation

Partial stack trace will look like this:

Caused by: java.lang.NullPointerException
	at org.grails.io.support.MainClassFinder.searchMainClass(MainClassFinder.groovy:38)
	at org.grails.compiler.injection.test.TestMixinTransformation.visit(TestMixinTransformation.java:113)
	at org.codehaus.groovy.transform.ASTTransformationVisitor.visitClass(ASTTransformationVisitor.java:197)
	at org.codehaus.groovy.transform.ASTTransformationVisitor$2.call(ASTTransformationVisitor.java:258)
	at org.codehaus.groovy.control.CompilationUnit.applyToPrimaryClassNodes(CompilationUnit.java:1143)
	... 8 more

[ddelponte]

@AntonPanikov, the last comment on the ticket at groovy/groovy-eclipse#850 is:

Verified on:
3.3.0.xx-201903212137-e1809

No issue, no errors. Thanks!

Can this ticket be closed or is it still an issue?

[AntonPanikov]

The other issue was fixed in: groovy/groovy-eclipse#850
But I think it was a workaround about the fact that MainClassFinder.groovy may throw NPE, while it should not. This issue was about providing more null safe code for the future versions of grails, that might or might not bite back at some point, see my original comment. It is up to you guys to do something about it or not.

Thanks!

[ddelponte]

PR created: #11323