Polishing.

Fix nullability arrangements.

See #3974

Author: mp911de

spring-data-jpa/src/main/java/org/springframework/data/jpa/provider/PersistenceProvider.java

@@ -332,6 +332,11 @@ public static PersistenceProvider fromEntityManagerFactory(EntityManagerFactory
 			} else if (AopUtils.isAopProxy(unwrapped)) {
 				unwrapped = (EntityManagerFactory) AopProxyUtils.getSingletonTarget(unwrapped);
 			}
+
+			if (unwrapped == null) {
+				throw new IllegalStateException(
+						"Unwrapping EntityManagerFactory from '%s' failed resulting in null".formatted(emf));
+			}
 		}
 
 		Class<?> entityManagerType = unwrapped.getClass();

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/aot/AotMetamodel.java

@@ -91,7 +91,7 @@ public void addTransformer(ClassTransformer classTransformer) {
 
 		this.entityManagerFactory = init(() -> {
 
-			managedTypes.stream().forEach(persistenceUnitInfo::addManagedClassName);
+			managedTypes.forEach(persistenceUnitInfo::addManagedClassName);
 
 			persistenceUnitInfo.setPersistenceProviderClassName(HibernatePersistenceProvider.class.getName());
 
@@ -104,7 +104,7 @@ public List<String> getManagedClassNames() {
 
 				@Override
 				public URL getPersistenceUnitRootUrl() {
-					return persistenceUnitRootUrl;
+					return persistenceUnitRootUrl != null ? persistenceUnitRootUrl : super.getPersistenceUnitRootUrl();
 				}
 
 			};

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/aot/JpaCodeBlocks.java

@@ -281,7 +281,9 @@ private CodeBlock applyRewrite(@Nullable String sort, @Nullable String dynamicRe
 			return builder.build();
 		}
 
-		private CodeBlock applyLimits(boolean exists, String pageable) {
+		private CodeBlock applyLimits(boolean exists, @Nullable String pageable) {
+
+			Assert.notNull(queries, "Queries must not be null");
 
 			Builder builder = CodeBlock.builder();
 

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/aot/QueriesFactory.java

@@ -25,6 +25,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.Properties;
 import java.util.function.Function;
@@ -99,7 +100,7 @@ private NamedQueries getNamedQueries(@Nullable RepositoryConfigurationSource con
 				PropertiesBasedNamedQueriesFactoryBean factoryBean = new PropertiesBasedNamedQueriesFactoryBean();
 				factoryBean.setLocations(resolver.getResources(location));
 				factoryBean.afterPropertiesSet();
-				return factoryBean.getObject();
+				return Objects.requireNonNull(factoryBean.getObject());
 			} catch (IOException e) {
 				throw new RuntimeException(e);
 			}

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/EmptyIntrospectedQuery.java

@@ -97,7 +97,7 @@ public QueryProvider rewrite(QueryEnhancer.QueryRewriteInformation rewriteInform
 
 	@Override
 	public PreprocessedQuery getQuery() {
-		return null;
+		throw new UnsupportedOperationException();
 	}
 
 	@Override

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/HqlSortedQueryTransformer.java

@@ -142,7 +142,7 @@ public QueryTokenStream visitJoinFunctionCall(HqlParser.JoinFunctionCallContext
 		QueryTokenStream tokens = super.visitJoinFunctionCall(ctx);
 
 		if (ctx.variable() != null && !tokens.isEmpty()) {
-			transformerSupport.registerAlias(tokens.getLast());
+			transformerSupport.registerAlias(tokens.getRequiredLast());
 		}
 
 		return tokens;

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/JpaQueryCreator.java

@@ -357,7 +357,7 @@ private JpqlQueryBuilder.Select doSelect(Sort sort) {
 		}
 	}
 
-	private JpqlQueryBuilder.Expression getDistanceExpression() {
+	private JpqlQueryBuilder.@Nullable Expression getDistanceExpression() {
 
 		DistanceFunction distanceFunction = DISTANCE_FUNCTIONS.get(provider.getScoringFunction());