[GROOVY-10064] STC infers incorrect type for closure parameter

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.8
• Component/s: Static Type Checker
• Assignee: Eric Milles
• Reporter: Christopher Smith
• Created: 27/Apr/21 23:22
• Updated: 22/Dec/23 11:38
• Resolved: 15/Apr/23 17:23

Description

I have this subroutine in some code managing DynamoDB tables; the types are from the Amazon 2 SDK and Vavr. The Either#fold method takes a Function<? super L, ? extends U> and a Function<? super R, ? extends U> (collapsing either a "left" or a "right" value into a single result). In this particular case, both types are the same DynamoDbTable, just representing different process states. The result type is a Try<DynamoDbTable>.

Aside from needing the workarounds that I think are related to GROOVY-10033 (.& and as CheckedRunnable), this code works as expected in GRECLIPSE, but it fails when compiled with groovyc.

    private Try<DynamoDbTable> waitForTableActive(Either<DynamoDbTable, DynamoDbTable> maybeActive) {
        maybeActive.fold(
            Try.&success, // we already determined it's active
            table -> {
                log.debug('waiting for table {} to become active', table.tableName())
                Try.success(table)
                    .andThenTry({ poll.until { checkActive(table).isLeft() } } as CheckedRunnable)
            }
        )
    }

    Either<DynamoDbTable, DynamoDbTable> checkActive(DynamoDbTable table) {}

Failed to execute goal org.codehaus.gmavenplus:gmavenplus-plugin:1.10.0:compile (default) on project azimuth-server: Error occurred while calling a method on a Groovy class from classpath.: InvocationTargetException: startup failed:
DynamoDbSchemaRegistryImpl.groovy: 134: [Static type checking] - Cannot find matching method io.vavr.control.Try#tableName(). Please check if the declared type is correct and if the method exists.
 @ line 134, column 68.
   r table {} to become active', table.tabl
                                 ^

DynamoDbSchemaRegistryImpl.groovy: 136: [Static type checking] - Cannot find matching method co.vendorflow.azimuth.server.infrastructure.data.dynamodb.DynamoDbSchemaRegistryImpl#checkActive(io.vavr.control.Try <T>). Please check if the declared type is correct and if the method exists.
 @ line 136, column 59.
   Try({ poll.until { checkActive(table).is
                                 ^

DynamoDbSchemaRegistryImpl.groovy: 136: [Static type checking] - Cannot find matching method java.lang.Object#isLeft(). Please check if the declared type is correct and if the method exists.
 @ line 136, column 48.
      .andThenTry({ poll.until { checkActiv
                                 ^

DynamoDbSchemaRegistryImpl.groovy: 131: [Static type checking] - Cannot call <U> io.vavr.control.Either <DynamoDbTable, DynamoDbTable>#fold(java.util.function.Function <? super software.amazon.awssdk.enhanced.dynamodb.DynamoDbTable, ? extends U>, java.util.function.Function <? super software.amazon.awssdk.enhanced.dynamodb.DynamoDbTable, ? extends U>) with arguments [groovy.lang.Closure <io.vavr.control.Try>, groovy.lang.Closure] 
 @ line 131, column 9.
           maybeActive.fold(
           ^

I have absolutely no idea how the STC gets the idea that the parameter of the outer closure should be a Try (the result should be), and it seems possible that the rest of the errors are a cascade from that initial mistake.

Adding an explicit (DynamoDbTable table) -> gets groovyc to compile it, but then I still need to say as Function everywhere or I get complaints that "closure is not a function".