(jena) branch main updated: GH-2795: Fix race condition in datatype registration

[arnebdt]

This is an automated email from the ASF dual-hosted git repository.

arnebdt pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/jena.git


The following commit(s) were added to refs/heads/main by this push:
     new 08209aea91 GH-2795: Fix race condition in datatype registration
08209aea91 is described below

commit 08209aea91d5aea22956866be6fb886d53653e63
Author: Ostrzyciel <ostrzycielnozyc...@gmail.com>
AuthorDate: Sat Oct 26 12:00:27 2024 +0200

    GH-2795: Fix race condition in datatype registration
---
 .../main/java/org/apache/jena/datatypes/TypeMapper.java | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/jena-core/src/main/java/org/apache/jena/datatypes/TypeMapper.java 
b/jena-core/src/main/java/org/apache/jena/datatypes/TypeMapper.java
index 5dd07fba12..821df17ae5 100644
--- a/jena-core/src/main/java/org/apache/jena/datatypes/TypeMapper.java
+++ b/jena-core/src/main/java/org/apache/jena/datatypes/TypeMapper.java
@@ -126,18 +126,16 @@ public class TypeMapper {
             // Plain literal
             return null;
         }
-        RDFDatatype dtype = uriToDT.get(uri);
-        if (dtype == null) {
+        return uriToDT.computeIfAbsent(uri, u -> {
             // Unknown datatype
             if (JenaParameters.enableSilentAcceptanceOfUnknownDatatypes) {
-                dtype = new BaseDatatype(uri);
-                registerDatatype(dtype);
+                // No need to update classToDT because 
BaseDatatype.getJavaClass is always null
+                return new BaseDatatype(u);
             } else {
                 throw new DatatypeFormatException(
                     "Attempted to created typed literal using an unknown 
datatype - " + uri);
             }
-        }
-        return dtype;
+        });
     }
 
     /**
@@ -183,6 +181,9 @@ public class TypeMapper {
 
     /**
      * Register a new datatype
+     * This will overwrite any existing registration for this datatype IRI.
+     * Comparisons of literals with different datatype instances will fail, so 
be careful
+     * if you are using this outside of initialization code.
      */
     public void registerDatatype(final RDFDatatype type) {
         uriToDT.put(type.getURI(), type);
@@ -194,6 +195,10 @@ public class TypeMapper {
 
     /**
      * Remove a datatype registration.
+     * <p>
+     * WARNING: This method may cause unexpected behavior if the datatype is 
still in use.
+     * If you unregister a datatype that is still used somewhere on the heap, 
literal comparisons with
+     * that datatype will fail.
      */
     public void unregisterDatatype(final RDFDatatype type) {
         uriToDT.remove(type.getURI());