[jira] [Comment Edited] (GROOVY-9517) CompileStatic typeCasting runtime error from Class Array to Class List

["Eric Milles (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GROOVY-9517?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17089707#comment-17089707 ] 

Eric Milles edited comment on GROOVY-9517 at 4/22/20, 2:09 PM:
---------------------------------------------------------------

I will have a look to see if this is still happening in Groovy 2.5+.  I think this has to do with the {{T[]}} return type of the array sort extension methods.

You can also assign the result of the sort call to a temp. And I don't think you need the "as File[]". You can use {{<=>}} operator in place of {{compareTo}}. And if you are comparing one property in natural order, you can use a variant of sort that just returns that property from the closure.
{code:groovy}
File file = new File('.')
listSortedFiles(file)

@groovy.transform.CompileStatic
void listSortedFiles(File directory) {
  File[] files = directory.listFiles()
  def sorted = files?.sort { it.name }
  for (file in sorted) {
    println file.name
  }
}
{code}


was (Author: emilles):
I will have a look to see if this is still happening in Groovy 2.5+.

You can also assign the result of the sort call to a temp.  And I don't think you need the "as File[]".  You can use {{<=>}} operator in place of {{compareTo}}.  And if you are comparing one property in natural order, you can use a variant of sort that just returns that property from the closure.

{code:groovy}
File file = new File('.')
listSortedFiles(file)

@groovy.transform.CompileStatic
void listSortedFiles(File directory) {
  File[] files = directory.listFiles()
  def sorted = files?.sort { it.name }
  for (file in sorted) {
    println file.name
  }
}
{code}

> CompileStatic typeCasting runtime error from Class Array to Class List
> ----------------------------------------------------------------------
>
>                 Key: GROOVY-9517
>                 URL: https://issues.apache.org/jira/browse/GROOVY-9517
>             Project: Groovy
>          Issue Type: Bug
>          Components: Static compilation
>    Affects Versions: 2.4.0, 2.4.19, 3.0.2, 3.0.3
>         Environment: Java: openjdk version "1.8.0_242"
> OS: OS X Catalina 10.15.3
> Groovy: 2.4.19
>            Reporter: David Estes
>            Assignee: Eric Milles
>            Priority: Major
>              Labels: CompileStatic
>
> After upgrading asset-pipeline-core from groovy 2.0.7 to 2.4.15 then 2.4.19 . A bug was identified with @CompileStatic not properly handling runtime type casting when sorting an Array instead of a List
>  
> Example
>  
> Create File TestFile.groovy
> {code:java}
> import groovy.transform.CompileStaticpublic class TestFile {	
>     static void main(String[] args) {
>         File file = new File('.')
>         TestFile testFile = new TestFile()
>         testFile.listSortedFiles(file)
>     }
>     @CompileStatic
>     void listSortedFiles(File directory) {
>         File[] files = directory.listFiles()
>         files = files?.sort { File a, File b -> a.name.compareTo b.name } as File[]
>         for(File file in files) {
>         }
>     }
> 	
> 		
> }
> {code}
> Then simply run:
> {code:java}
> groovy TestFile.groovy
> {code}
>  
> Exception:
>  
> {code:java}
> Caught: java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to [Ljava.io.File;
> java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to [Ljava.io.File;
> 	at TestFile.listSortedFiles(TestFile.groovy:15)
> 	at TestFile$listSortedFiles.call(Unknown Source)
> 	at TestFile.main(TestFile.groovy:8)
> {code}
>  



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