[
https://issues.apache.org/jira/browse/COMMONSRDF-51?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15834333#comment-15834333
]
ASF GitHub Bot commented on COMMONSRDF-51:
------------------------------------------
Github user stain commented on the issue:
https://github.com/apache/commons-rdf/pull/30
I added equivalent tests for `Graph` add/contains/remove, and this fails
for Jena:
```
java.lang.AssertionError
at org.junit.Assert.fail(Assert.java:86)
at org.junit.Assert.assertTrue(Assert.java:41)
at org.junit.Assert.assertFalse(Assert.java:64)
at org.junit.Assert.assertFalse(Assert.java:74)
at
org.apache.commons.rdf.api.AbstractGraphTest.containsLanguageTagsCaseInsensitive(AbstractGraphTest.java:415)
...
```
basically if I add `"Hello"@EN-GB` to a Jena Graph and then try to remove
`"Hello"@en-GB` then the statement remains in the graph as `"Hello"@EN-GB`.
How can we fix this? It would not be enough to just lowercase in all
Commons RDF methods with Jena Literal language tags, as the Jena graph/model
could be populated through other means (e.g. parsing a file).
> RDF-1.1 specifies that language tags need to be compared using lower-case
> -------------------------------------------------------------------------
>
> Key: COMMONSRDF-51
> URL: https://issues.apache.org/jira/browse/COMMONSRDF-51
> Project: Apache Commons RDF
> Issue Type: Bug
> Components: api
> Affects Versions: 0.3.0
> Reporter: Peter Ansell
> Assignee: Stian Soiland-Reyes
>
> The [RDF-1.1 specification states that the [value space of Literal language
> tags is
> lowercase|https://www.w3.org/TR/rdf11-concepts/#section-Graph-Literal], which
> does not conflict with the case-insensitive specification in BCP47. The
> Literal.equals and Literal.hashCode API contracts should specify that
> language tags must be compared using lowercase, even if they are otherwise
> stored and returned as upper-case by getLanguageTag. The API currently has
> incorrect language by saying "character-by-character" for language tag
> comparisons, as that implies case-sensitive comparisons are used.
> The lowercasing must also be done using a locale that is consistent (known
> example where lowercase and uppercase do not roundtrip as expected for
> US-ASCII characters is Turkish [1]), so I would recommend actually stating
> that .toLowerCase(Locale.ENGLISH) is used.
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