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https://issues.apache.org/jira/browse/GROOVY-6837?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17474491#comment-17474491
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Paul King commented on GROOVY-6837:
-----------------------------------
I think the LUB idea is too fancy in this scenario. Our current behavior is as
follows:
{code}
import static groovy.test.GroovyAssert.shouldFail
String[] words = ['ant', 'bee']
Integer[] nums = [5, 10]
def result = words + nums // (1)
assert result.class == Object[]
assert result*.class == [String, String, Integer, Integer] // ['ant', 'bee', 5,
10]
words = words + nums // (2)
assert words.class == String[]
assert words*.class == [String, String, String, String] // ['ant', 'bee', '5',
'10'] due to coercion
result = nums + ['cat', 'dog'] // (3)
assert result.class == Object[]
assert result*.class == [Integer, Integer, String, String]
shouldFail(ClassCastException) {
nums = nums + ['cat', 'dog'] // (4) no auto coercion
}
{code}
I don't think it is easy to justify why (1) and (2) provide different behavior
given the RHS is the same in both. Ditto for (3) and (4). I think the behavior
offered in (2) and (4) should be what {{plus}} always provides.
I think we can provide an additional (set of) method(s) named {{addAll}} (or
{{merge}} or {{union}} or similar) that returns {{Object[]}} and provides the
current behavior shown in (1) and (3). One could imagine overloaded variants
even allowing the array return type/component type to be specified, though I
wouldn't go that far to start with until we see such a need.
> String[] + String[] gives Object[]
> ----------------------------------
>
> Key: GROOVY-6837
> URL: https://issues.apache.org/jira/browse/GROOVY-6837
> Project: Groovy
> Issue Type: Bug
> Components: groovy-runtime
> Affects Versions: 2.3.1
> Reporter: Dmitry Ovchinnikov
> Assignee: Eric Milles
> Priority: Major
> Time Spent: 20m
> Remaining Estimate: 0h
>
> {code:java}
> def a1 = ["a", "b"] as String[], a2 = ["c", "d"] as String[];
> def concatenated = a1 + a2;
> java.nio.file.Paths.get("parent", concatenated)
> {code}
> ==>
> {noformat}
> groovy.lang.MissingMethodException: No signature of method: static
> java.nio.file.Paths.get() is applicable for argument types:
> (java.lang.String, [Ljava.lang.Object;) values: [parent, [a, b, c, d]]
> Possible solutions: get(java.lang.String, [Ljava.lang.String;),
> get(java.net.URI), grep(), getAt(java.lang.String), wait(), any()
> at
> groovy.lang.MetaClassImpl.invokeStaticMissingMethod(MetaClassImpl.java:1373)
> at groovy.lang.MetaClassImpl.invokeStaticMethod(MetaClassImpl.java:1359)
> at
> org.codehaus.groovy.runtime.callsite.StaticMetaClassSite.call(StaticMetaClassSite.java:50)
> at
> org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
> at
> org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
> at
> org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:120)
> at ideaGroovyConsole.run(ideaGroovyConsole.groovy:4)
> at
> groovy.lang.GroovyShell.runScriptOrMainOrTestOrRunnable(GroovyShell.java:258)
> at groovy.lang.GroovyShell.run(GroovyShell.java:502)
> at groovy.lang.GroovyShell.run(GroovyShell.java:481)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:606)
> at
> org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoCachedMethodSite.invoke(PogoMetaMethodSite.java:166)
> at
> org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite.call(PogoMetaMethodSite.java:68)
> at
> org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:120)
> at console.run(console.txt:25)
> {noformat}
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