Fix NPE with missing getIndexedProperties (#11721)

Author: dstepanov

core-processor/src/main/java/io/micronaut/inject/beans/visitor/BeanIntrospectionWriter.java

@@ -53,6 +53,7 @@
 import io.micronaut.inject.writer.ClassWriterOutputVisitor;
 import io.micronaut.inject.writer.DispatchWriter;
 import io.micronaut.inject.writer.EvaluatedExpressionProcessor;
+import io.micronaut.inject.writer.GenUtils;
 import io.micronaut.inject.writer.MethodGenUtils;
 import io.micronaut.inject.writer.OriginatingElements;
 import io.micronaut.sourcegen.model.AnnotationDef;
@@ -905,6 +906,7 @@ private MethodDef getGetIndexedProperties() {
         if (indexByAnnotations.isEmpty()) {
             return null;
         }
+
         TypeDef returnType = TypeDef.of(GET_INDEXED_PROPERTIES.getReturnType());
         return MethodDef.builder(GET_INDEXED_PROPERTIES.getName())
             .returns(returnType)
@@ -920,7 +922,7 @@ private MethodDef getGetIndexedProperties() {
                                     GET_BP_INDEXED_SUBSET_METHOD,
                                     introspectionTypeDef.getStaticField(annotationIndexFields.get(annotationName))
                                 )
-                        )), ExpressionDef.nullValue())
+                        )), GenUtils.listOf(List.of()))
                     .returning());
     }
 

inject-java-test/src/test/groovy/io/micronaut/inject/visitor/beans/BeanIntrospectionSpec.groovy

@@ -14,6 +14,7 @@ import io.micronaut.context.visitor.ConfigurationReaderVisitor
 import io.micronaut.core.annotation.Introspected
 import io.micronaut.core.annotation.NextMajorVersion
 import io.micronaut.core.annotation.NonNull
+import io.micronaut.core.annotation.Nullable
 import io.micronaut.core.beans.BeanIntrospection
 import io.micronaut.core.beans.BeanIntrospectionReference
 import io.micronaut.core.beans.BeanIntrospector
@@ -2596,6 +2597,52 @@ public class ValidatedConfig {
         introspection.getIndexedProperties(Constraint.class).size() == 2
     }
 
+    void "not found indexed properties"() {
+        BeanIntrospection introspection = buildBeanIntrospection('test.ValidatedConfig','''\
+package test;
+
+import io.micronaut.context.annotation.ConfigurationProperties;
+
+import jakarta.validation.constraints.NotNull;
+import jakarta.validation.constraints.NotBlank;
+import java.net.URL;
+
+@ConfigurationProperties("foo.bar")
+public class ValidatedConfig {
+
+    @NotNull
+    URL url;
+
+    @NotBlank
+    protected String name;
+
+    public URL getUrl() {
+        return url;
+    }
+
+    public void setUrl(URL url) {
+        this.url = url;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}
+
+
+''')
+        expect:
+        introspection != null
+        !introspection.getIndexedProperties(Constraint.class).isEmpty()
+        introspection.getIndexedProperties(Constraint.class).size() == 2
+        introspection.getIndexedProperty(Nullable.class).isEmpty()
+        introspection.getIndexedProperties(Nullable.class).isEmpty()
+    }
+
     void "test generate bean introspection for @ConfigurationProperties with validation rules on fields and custom getter"() {
         BeanIntrospection introspection = buildBeanIntrospection('test.ValidatedConfig', '''\
 package test;