[
https://issues.apache.org/jira/browse/GROOVY-11807?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18092261#comment-18092261
]
ASF GitHub Bot commented on GROOVY-11807:
-----------------------------------------
Copilot commented on code in PR #2641:
URL: https://github.com/apache/groovy/pull/2641#discussion_r3489911417
##########
src/main/java/org/codehaus/groovy/runtime/DefaultGroovyMethods.java:
##########
@@ -19155,6 +19155,61 @@ public static <K, V> Map<K, V> withDefault(Map<K, V>
self, boolean autoGrow, boo
return MapWithDefault.newInstance(self, autoGrow, autoShrink, init);
}
+ /**
+ * Decorates the given Map with a default value supplied by a closure, as
per
+ * {@link #withDefault(Map, Closure)}, but the returned map additionally
enforces its
+ * key and value types at runtime. Looking up (and so auto-growing for) a
key that is
+ * not an instance of {@code keyType} throws {@link ClassCastException} at
the point of
+ * misuse, rather than silently inserting a wrong-typed key that only
surfaces later
+ * (for example when reading {@code keySet()}). The check is provided by
decorating an
+ * {@link #asChecked(Map, Class, Class) asChecked} view, so direct
mutation such as
+ * {@code map[key] = value} is guarded too.
+ * <pre class="language-groovy">
+ * def m = [:].withDefault(Number, Object){ 42 }
+ * assert m[1] == 42 // a compatible key grows the map
+ * // m['x'] // would throw ClassCastException
(incompatible key)
+ * </pre>
Review Comment:
The GroovyDoc example for the key+value checked overload uses `Object` as
`valueType`, which effectively disables value checking and undermines the
method’s stated purpose (runtime enforcement of both key and value types).
Using a concrete `valueType` (e.g. `String`) and showing an incompatible value
case would make the example accurate and less confusing.
> MapWithDefault can break type safety of key set
> -----------------------------------------------
>
> Key: GROOVY-11807
> URL: https://issues.apache.org/jira/browse/GROOVY-11807
> Project: Groovy
> Issue Type: Bug
> Components: groovy-jdk
> Reporter: Eric Milles
> Assignee: Paul King
> Priority: Major
>
> {code}
> Map<Number,?> map = [:].withDefault{ null }
> assert map.get('x') == null
> Number k = map.keySet()[0]
> {code}
> GroovyCastException: Cannot cast object 'x' with class 'java.lang.String' to
> class 'java.lang.Number'
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
