[jira] [Comment Edited] (GROOVY-9986) CLONE - STC does not report type mismatches for coerced list expression

["Paul King (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GROOVY-9986?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17303159#comment-17303159 ] 

Paul King edited comment on GROOVY-9986 at 3/17/21, 7:21 AM:
-------------------------------------------------------------

See also comments in GROOVY-9985.

Currently "{{val as MyClass}}" becomes (more or less) "{{asType(val, MyClass)}}" and then type checking is run and since {{asType}} exists for {{Object}} and any Class, checking always succeeds. We could try to make `as` coercion smarter and know about the current built-in coercions or provide a type checker which did the same that could be optionally applied.

Secondly, the {{List}} to array coercion doesn't currently attempt to call {{asType(listElement, componentType)}} for each of its elements. We could consider doing that but have resisted previously since it is an extra level of magic which users can do themselves, e.g. for valid inputs:
{code}
Integer[] arr2 = [1, "42", new Date().time].collect{ it as Integer }
{code}
Again, "as" is acting as an escape hatch here, so it doesn't really help in detecting an invalid case such as adding "two" into above list.


was (Author: paulk):
See also comments in GROOVY-9985.

Currently {{val as MyClass}} becomes (more or less) {{asType(val, MyClass)}} and then type checking is run and since {{asType}} exists for {{Object}} and any Class, checking always succeeds. We could try to make `as` coercion smarter and know about the current built-in coercions or provide a type checker which did the same that could be optionally applied.

Secondly, the {{List}} to array coercion doesn't currently attempt to call {{asType(listElement, componentType)}} for each of its elements. We could consider doing that but have resisted previously since it is an extra level of magic which users can do themselves, e.g. for valid inputs:
{code}
Integer[] arr2 = [1, "42", new Date().time].collect{ it as Integer }
{code}
Again, "as" is acting as an escape hatch here, so it doesn't really help in detecting an invalid case such as adding "two" into above list.

> CLONE - STC does not report type mismatches for coerced list expression
> -----------------------------------------------------------------------
>
>                 Key: GROOVY-9986
>                 URL: https://issues.apache.org/jira/browse/GROOVY-9986
>             Project: Groovy
>          Issue Type: Bug
>          Components: Static Type Checker
>            Reporter: Thodoris Sotiropoulos
>            Assignee: Paul King
>            Priority: Major
>
> The following program compiles (with @CompileStatic), although it shouldn't.
> {code:java}
> public class Main {
>     public static void main(String[] args) {
>       // Integer[] arr = new Integer[]{1, "str"}; // does not report error (see GROOVY-9985)
>       Integer[] arr2 = [1, "fda"] as Integer[] // does not report error
>     }
> }
> {code}
> As a result, an exception is thrown at runtime
> {code:java}
> Exception in thread "main" org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object 'str' with class 'java.lang.String' to class 'java.lang.Integer'
>         at org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation.castToNumber(DefaultTypeTransformation.java:172)
>         at org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation.continueCastOnNumber(DefaultTypeTransformation.java:282)
>         at org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation.castToType(DefaultTypeTransformation.java:243)
>         at org.codehaus.groovy.vmplugin.v8.IndyInterface.fromCache(IndyInterface.java:318)
>         at Main.main(test.groovy:4)
> {code}
> Tested on [https://github.com/apache/groovy/commit/f0eea862549529ef4e93fafe337f86dd4ac98751]
>  



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