[jira] [Commented] (GROOVY-9183) Issue using @MapConstructor and @NamedVariant

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

    [ https://issues.apache.org/jira/browse/GROOVY-9183?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16984671#comment-16984671 ] 

Eric Milles commented on GROOVY-9183:
-------------------------------------

The AST transform creates a method that has essentially this form:
{code:groovy}
public static CsvRowMapper parse(Map namedArgs, Reader reader) {
  ...
  return this.parse((Settings) [separator: namedArgs.separator, headers: namedArgs.headers, ...], reader)
}
{code}

Since your properties have initialization expressions, I think it would be better to write each map entry expression this way:
{{headers: namedArgs.getOrDefault('headers', prop.getInitialExpression())}}

> Issue using @MapConstructor and @NamedVariant
> ---------------------------------------------
>
>                 Key: GROOVY-9183
>                 URL: https://issues.apache.org/jira/browse/GROOVY-9183
>             Project: Groovy
>          Issue Type: Bug
>          Components: groovy-runtime
>    Affects Versions: 2.5.7
>            Reporter: Eric Berry
>            Priority: Major
>              Labels: named-parameters
>         Attachments: MapConstructor.png, NamedVariant.png
>
>
> I have a static method marked with {{@NamedVariant}}, that takes a "Configuration" object as a parameter, which is marked with {{@NamedDelegate}}. The "Configuration" object is defined as a static inner class marked with {{@Immutable}}.
>  
> My Class:
> {quote}class CsvRowMapper \{
>     private final Settings settings
>     @NamedVariant
>     CsvRowMapper(Settings settings) \{
>         this.settings = settings
>     }
>     *@NamedVariant*
>     *static CsvRowMapper parse(@NamedDelegate Settings settings, Reader reader) {*
>         *new CsvRowMapper(settings).parse(reader)*
>     *}*
>     CsvRowMapper parse(Reader source) \{
>         // do work here
>         return this
>     }
>     *@Immutable*
>     *static class Settings {*
>         *String separator = ','*
>         *boolean headers = true*
>         *int headersRow = 0*
>         *int firstDataRow = 1*
>     *}*
> }{quote}
>  
> I've highlighted the important parts. The issue is when I use this class like:
> {code}
> CsvRowMapper.parse(*separator: '\t'*, tsvFileReader)
> {code}
>  
> I get an {{GroovyCastException}} because it's trying to set {{headersRow}} or {{firstDataRow}} to {{null}}:
>  
> {noformat}
> org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object '\{separator= , headers=null, headersRow=null, firstDataRow=null}'
>   with class 'java.util.LinkedHashMap' to class 'CsvRowMapper$Settings'
>   due to: org.codehaus.groovy.runtime.typehandling.GroovyCastException:
>     Cannot cast object 'null' with class 'null' to class 'int'. Try 'java.lang.Integer' instead
> {noformat}
>  
> Even though there are default values for each setting.
>  
> I loaded up this into GroovyConsole, and I think the issue is that the {{@NameVariant}} version of the `parse` method is creating a map with ALL keys for the {{@NamedDelegate}} {{Settings}} class (See NamedVariant.png).
>  
> Furthermore the {{@Immutable}} annotation adds {{@MapConstructor}} to my {{Settings}} class, which only checks if the given map contains the *`key`*, not also if it has a `value` (See MapConstructor.png).
>  
> The {{@NamedVariant}} passes a map containing null values for all keys not supplied during method execution, and {{@MapConstructor}} only checks if the given map has the key, not a value.
>  



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