HHH-19050 Allow configuration of EntityManagerFactoryBuilderImpl to override the BytecodeProvider instance

hibernate-core/src/main/java/org/hibernate/bytecode/enhance/spi/EnhancementContext.java

@@ -4,6 +4,8 @@
  */
 package org.hibernate.bytecode.enhance.spi;
 
+import org.hibernate.bytecode.spi.BytecodeProvider;
+
 import jakarta.persistence.metamodel.Type;
 import org.hibernate.Incubating;
 
@@ -156,4 +158,15 @@ public interface EnhancementContext {
 	default UnsupportedEnhancementStrategy getUnsupportedEnhancementStrategy() {
 		return UnsupportedEnhancementStrategy.SKIP;
 	}
+
+	/**
+	 * Allows to force the use of a specific instance of BytecodeProvider to perform the enhancement.
+	 * @return When returning {code null} the default implementation will be used. Only return a different instance if
+	 * you need to override the default implementation.
+	 */
+	@Incubating
+	default BytecodeProvider getBytecodeProvider() {
+		return null;
+	}
+
 }

hibernate-core/src/main/java/org/hibernate/cfg/BytecodeSettings.java

@@ -26,6 +26,17 @@ public interface BytecodeSettings {
 	@Deprecated( forRemoval = true )
 	String BYTECODE_PROVIDER = "hibernate.bytecode.provider";
 
+	/**
+	 * This is similar to the now deprecated legacy property {@code hibernate.bytecode.provider} except
+	 * it's used specifically to pass an existing instance of a {@link org.hibernate.bytecode.spi.BytecodeProvider};
+	 * this happens to also allow to override the implementation, but is primarily intended to allow reusing a
+	 * specific instance; this could be useful when the implementation benefits from internal caches.
+	 * When not set, Hibernate will create its default implementation.
+	 *
+	 * @settingDefault {@code null}
+	 */
+	String BYTECODE_PROVIDER_INSTANCE = "hibernate.enhancer.bytecodeprovider.instance";
+
 	/**
 	 * Enable association management feature in runtime bytecode enhancement
 	 *

hibernate-core/src/main/java/org/hibernate/jpa/boot/internal/EntityManagerFactoryBuilderImpl.java

@@ -52,6 +52,7 @@
 import org.hibernate.bytecode.enhance.spi.EnhancementException;
 import org.hibernate.bytecode.enhance.spi.UnloadedClass;
 import org.hibernate.bytecode.enhance.spi.UnloadedField;
+import org.hibernate.bytecode.spi.BytecodeProvider;
 import org.hibernate.bytecode.spi.ClassTransformer;
 import org.hibernate.cfg.AvailableSettings;
 import org.hibernate.engine.jdbc.connections.spi.ConnectionProvider;
@@ -113,6 +114,7 @@
 import static org.hibernate.cfg.AvailableSettings.TRANSACTION_COORDINATOR_STRATEGY;
 import static org.hibernate.cfg.AvailableSettings.URL;
 import static org.hibernate.cfg.AvailableSettings.USER;
+import static org.hibernate.cfg.BytecodeSettings.BYTECODE_PROVIDER_INSTANCE;
 import static org.hibernate.cfg.BytecodeSettings.ENHANCER_ENABLE_ASSOCIATION_MANAGEMENT;
 import static org.hibernate.cfg.BytecodeSettings.ENHANCER_ENABLE_DIRTY_TRACKING;
 import static org.hibernate.cfg.BytecodeSettings.ENHANCER_ENABLE_LAZY_INITIALIZATION;
@@ -422,6 +424,11 @@ protected EnhancementContext getEnhancementContext(
 			final boolean dirtyTrackingEnabled,
 			final boolean lazyInitializationEnabled,
 			final boolean associationManagementEnabled ) {
+		final Object propValue = configurationValues.get( BYTECODE_PROVIDER_INSTANCE );
+		if ( propValue != null && ( ! ( propValue instanceof BytecodeProvider ) ) ) {
+			throw new PersistenceException( "Property " + BYTECODE_PROVIDER_INSTANCE + " was set to '" + propValue + "', which is not compatible with the expected type " + BytecodeProvider.class );
+		}
+		final BytecodeProvider overriddenBytecodeProvider = (BytecodeProvider) propValue;
 		return new DefaultEnhancementContext() {
 
 			@Override
@@ -461,6 +468,11 @@ public boolean doExtendedEnhancement(UnloadedClass classDescriptor) {
 				// doesn't make any sense to have extended enhancement enabled at runtime. we only enhance entities anyway.
 				return false;
 			}
+
+			@Override
+			public BytecodeProvider getBytecodeProvider() {
+				return overriddenBytecodeProvider;
+			}
 		};
 	}
 

hibernate-core/src/main/java/org/hibernate/jpa/internal/enhance/EnhancingClassTransformerImpl.java

@@ -35,7 +35,8 @@ public class EnhancingClassTransformerImpl implements ClassTransformer {
 	public EnhancingClassTransformerImpl(EnhancementContext enhancementContext) {
 		Objects.requireNonNull( enhancementContext );
 		this.enhancementContext = enhancementContext;
-		this.bytecodeProvider = BytecodeProviderInitiator.buildDefaultBytecodeProvider();
+		final BytecodeProvider overriddenProvider = enhancementContext.getBytecodeProvider();
+		this.bytecodeProvider = overriddenProvider == null ? BytecodeProviderInitiator.buildDefaultBytecodeProvider() : overriddenProvider;
 	}
 
 	@Override