Scott Murphy Heiberg created GROOVY-12534:
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Summary: SC: a property defined by an extension method of List is
read from each element of the list
Key: GROOVY-12534
URL: https://issues.apache.org/jira/browse/GROOVY-12534
Project: Groovy
Issue Type: Bug
Components: Static compilation
Affects Versions: 6.0.0
Reporter: Scott Murphy Heiberg
Under {{@CompileStatic}}, a property whose getter is an extension method of
{{List}}, or of a class that implements {{List}}, is compiled as a property of
the list's elements: the getter is called once for each element, with the
element cast to the extension's receiver type. With this extension module:
{code:java}
package demo;
import java.util.List;
public class ListExtension {
public static String getJoined(List<String> self) { return String.join(",",
self); }
}
{code}
{code:groovy}
@groovy.transform.CompileStatic
class C {
def test(List<String> words) { words.joined }
}
new C().test(['x', 'y']) // GroovyCastException: Cannot cast object 'x' with
class 'java.lang.String' to class 'java.util.List'
{code}
{{words.getJoined()}} returns 'x,y' in every mode, and dynamic Groovy and
{{@TypeChecked}} return 'x,y' for {{words.joined}} too. On an empty list,
{{words.joined}} evaluates to {{[]}} instead of an empty string.
{{StaticCompilationVisitor.existsProperty}} marks the property expression
spread-safe when the getter's declaring class implements {{List}} but does not
declare the getter, which is meant for a property of the element type. The
declaring class of an extension method is its receiver type, which never
declares it. Extension getters declared for {{Collection}} or {{Iterable}},
such as {{getIndices}} and {{isSorted}}, are not affected.
{{DefaultGroovyMethodsSTCTest.testPropertySemantics2}}, which
{{StaticCompileDGMTest}} also runs, keeps the property forms of
{{getSequence(List)}} and {{getString(List)}} from {{TestStringExtension}}
commented out. Seen in 4.0.33, 5.0.8, 6.0.0 and master.
Expected: the property calls the extension getter on the list, as in dynamic
Groovy and {{@TypeChecked}}.
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