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Posted to issues@commons.apache.org by "Matt Benson (Created) (JIRA)" <ji...@apache.org> on 2011/11/18 00:55:52 UTC
[jira] [Created] (LANG-776) TypeUtilsTest contains incorrect type
assignability assertion due to lost/skipped type variable information
during the decision process
TypeUtilsTest contains incorrect type assignability assertion due to lost/skipped type variable information during the decision process
---------------------------------------------------------------------------------------------------------------------------------------
Key: LANG-776
URL: https://issues.apache.org/jira/browse/LANG-776
Project: Commons Lang
Issue Type: Bug
Components: lang.reflect.*
Affects Versions: 3.1
Reporter: Matt Benson
Assignee: Matt Benson
{{TypeUtilsTest}} originally contained the following under #{{testIsAssignable()}}:
{code}
Assert.assertTrue("WRONG!", TypeUtils.isAssignable(dingType, disType));
{code}
For background:
{code}
public interface This<K, V> {
}
public class Other<T> implements This<String, T> {
}
public class Thing<Q> extends Other<B> {
}
{code}
{{<B>}} refers to a type parameter on the {{TypeUtilsTest}} class itself.
{{disType}} and {{dingType}} refer to the generic types of the following fields, respectively:
{code}
public This<String, String> dis;
public Thing ding;
{code}
Thus the assertion in question declares that type {{Thing}} is assignable to {{This<String, String>}}. If we start at {{This}} we can see that the implementing class {{Other}} maps its {{T}} type parameter to the {{V}} type parameter of {{This}}. From this point we can proceed down to {{Thing}} and see that it maps the {{B}} type parameter of the enclosing {{TypeUtilsTest}} class to the {{T}} type parameter of {{Other}}. Thus it is fairly obvious that only a {{TypeUtilsTest<String>.Thing}} is assignable to {{This<String, String>}}. From this we can determine that the intent of the message in the original test assertion must indeed have been to flag an incorrect assertion. This is the associated bug report.
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[jira] [Resolved] (LANG-776) TypeUtilsTest contains incorrect type
assignability assertion due to lost/skipped type variable information
during the decision process
Posted by "Matt Benson (Resolved) (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/LANG-776?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Matt Benson resolved LANG-776.
------------------------------
Resolution: Fixed
Fix Version/s: 3.2
rev 1203429
> TypeUtilsTest contains incorrect type assignability assertion due to lost/skipped type variable information during the decision process
> ---------------------------------------------------------------------------------------------------------------------------------------
>
> Key: LANG-776
> URL: https://issues.apache.org/jira/browse/LANG-776
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.reflect.*
> Affects Versions: 3.1
> Reporter: Matt Benson
> Assignee: Matt Benson
> Fix For: 3.2
>
>
> {{TypeUtilsTest}} originally contained the following under #{{testIsAssignable()}}:
> {code}
> Assert.assertTrue("WRONG!", TypeUtils.isAssignable(dingType, disType));
> {code}
> For background:
> {code}
> public interface This<K, V> {
> }
> public class Other<T> implements This<String, T> {
> }
> public class Thing<Q> extends Other<B> {
> }
> {code}
> {{<B>}} refers to a type parameter on the {{TypeUtilsTest}} class itself.
> {{disType}} and {{dingType}} refer to the generic types of the following fields, respectively:
> {code}
> public This<String, String> dis;
> public Thing ding;
> {code}
> Thus the assertion in question declares that type {{Thing}} is assignable to {{This<String, String>}}. If we start at {{This}} we can see that the implementing class {{Other}} maps its {{T}} type parameter to the {{V}} type parameter of {{This}}. From this point we can proceed down to {{Thing}} and see that it maps the {{B}} type parameter of the enclosing {{TypeUtilsTest}} class to the {{T}} type parameter of {{Other}}. Thus it is fairly obvious that only a {{TypeUtilsTest<String>.Thing}} is assignable to {{This<String, String>}}. From this we can determine that the intent of the message in the original test assertion must indeed have been to flag an incorrect assertion. This is the associated bug report.
--
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