refactor: declare org.testng.internal.annotations null-marked

testng-core-api/src/main/java/org/testng/internal/annotations/IAnnotationFinder.java

@@ -3,6 +3,7 @@
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import java.util.List;
+import org.jspecify.annotations.Nullable;
 import org.testng.ITestNGMethod;
 import org.testng.annotations.IAnnotation;
 import org.testng.internal.ConstructorOrMethod;
@@ -19,7 +20,7 @@ public interface IAnnotationFinder {
    * @param <A> The expected {@link IAnnotation} type
    * @return The annotation on the class or null if none found.
    */
-  <A extends IAnnotation> A findAnnotation(Class<?> cls, Class<A> annotationClass);
+  <A extends IAnnotation> @Nullable A findAnnotation(Class<?> cls, Class<A> annotationClass);
 
   /**
    * @param m - The corresponding {@link Method}
@@ -28,14 +29,15 @@ public interface IAnnotationFinder {
    * @return The annotation on the method. If not found, return the annotation on the declaring
    *     class. If not found, return null.
    */
-  <A extends IAnnotation> A findAnnotation(Method m, Class<A> annotationClass);
+  <A extends IAnnotation> @Nullable A findAnnotation(Method m, Class<A> annotationClass);
 
-  <A extends IAnnotation> A findAnnotation(ITestNGMethod m, Class<A> annotationClass);
+  <A extends IAnnotation> @Nullable A findAnnotation(ITestNGMethod m, Class<A> annotationClass);
 
-  <A extends IAnnotation> A findAnnotation(ConstructorOrMethod com, Class<A> annotationClass);
+  <A extends IAnnotation> @Nullable A findAnnotation(
+      ConstructorOrMethod com, Class<A> annotationClass);
 
-  <A extends IAnnotation> A findAnnotation(
-      Class<?> clazz, Method m, java.lang.Class<A> annotationClass);
+  <A extends IAnnotation> @Nullable A findAnnotation(
+      @Nullable Class<?> clazz, Method m, java.lang.Class<A> annotationClass);
 
   /**
    * @param cons - The corresponding {@link Constructor}
@@ -44,7 +46,7 @@ <A extends IAnnotation> A findAnnotation(
    * @return The annotation on the method. If not found, return the annotation on the declaring
    *     class. If not found, return null.
    */
-  <A extends IAnnotation> A findAnnotation(Constructor<?> cons, Class<A> annotationClass);
+  <A extends IAnnotation> @Nullable A findAnnotation(Constructor<?> cons, Class<A> annotationClass);
 
   /**
    * @param cls - The corresponding class.

testng-core-api/src/main/java/org/testng/internal/annotations/IDataProvidable.java

@@ -1,14 +1,18 @@
 package org.testng.internal.annotations;
 
+import org.jspecify.annotations.Nullable;
+
 /** A trait shared by all the annotations that have dataProvider/dataProviderClass attributes. */
 public interface IDataProvidable {
   String getDataProvider();
 
   void setDataProvider(String v);
 
+  /** @return The class holding the data provider, or {@code null} when none was named. */
+  @Nullable
   Class<?> getDataProviderClass();
 
-  void setDataProviderClass(Class<?> v);
+  void setDataProviderClass(@Nullable Class<?> v);
 
   String getDataProviderDynamicClass();
 

testng-core-api/src/main/java/org/testng/internal/annotations/package-info.java

@@ -0,0 +1,5 @@
+/** Reads TestNG's annotations off classes, methods and constructors, and models what they say. */
+@NullMarked
+package org.testng.internal.annotations;
+
+import org.jspecify.annotations.NullMarked;

testng-core/src/main/java/org/testng/internal/annotations/AnnotationHelper.java

@@ -10,6 +10,7 @@
 import java.util.Map;
 import java.util.Objects;
 import java.util.function.Predicate;
+import org.jspecify.annotations.Nullable;
 import org.testng.ITestNGMethod;
 import org.testng.ITestObjectFactory;
 import org.testng.annotations.IAnnotation;
@@ -63,27 +64,32 @@ private AnnotationHelper() {
     // Utility class.defeat instantiation.
   }
 
-  public static ITestAnnotation findTest(IAnnotationFinder finder, Class<?> cls) {
+  public static @Nullable ITestAnnotation findTest(IAnnotationFinder finder, Class<?> cls) {
     return finder.findAnnotation(cls, ITestAnnotation.class);
   }
 
-  public static ITestAnnotation findTest(IAnnotationFinder finder, Method m) {
+  public static @Nullable ITestAnnotation findTest(IAnnotationFinder finder, Method m) {
     return finder.findAnnotation(m, ITestAnnotation.class);
   }
 
-  public static ITestAnnotation findTest(IAnnotationFinder finder, ITestNGMethod m) {
+  public static @Nullable ITestAnnotation findTest(IAnnotationFinder finder, ITestNGMethod m) {
     return finder.findAnnotation(m, ITestAnnotation.class);
   }
 
-  public static IFactoryAnnotation findFactory(IAnnotationFinder finder, Method m) {
+  public static @Nullable IFactoryAnnotation findFactory(IAnnotationFinder finder, Method m) {
     return finder.findAnnotation(m, IFactoryAnnotation.class);
   }
 
-  public static IFactoryAnnotation findFactory(IAnnotationFinder finder, Constructor<?> c) {
+  public static @Nullable IFactoryAnnotation findFactory(
+      IAnnotationFinder finder, Constructor<?> c) {
     return finder.findAnnotation(c, IFactoryAnnotation.class);
   }
 
-  public static IConfigurationAnnotation findConfiguration(
+  /**
+   * @return The configuration annotation carried by the method, or {@code null} when it carries
+   *     none.
+   */
+  public static @Nullable IConfigurationAnnotation findConfiguration(
       IAnnotationFinder finder, ConstructorOrMethod m) {
     IConfigurationAnnotation result = null;
     boolean ignoreFailure = false;
@@ -137,21 +143,22 @@ public static IConfigurationAnnotation findConfiguration(
     return result;
   }
 
-  public static IConfigurationAnnotation findConfiguration(IAnnotationFinder finder, Method m) {
+  public static @Nullable IConfigurationAnnotation findConfiguration(
+      IAnnotationFinder finder, Method m) {
     return findConfiguration(finder, new ConstructorOrMethod(m));
   }
 
   private static IConfigurationAnnotation createConfiguration(
-      IConfigurationAnnotation bs,
-      IConfigurationAnnotation as,
-      IConfigurationAnnotation bt,
-      IConfigurationAnnotation at,
-      IConfigurationAnnotation bg,
-      IConfigurationAnnotation ag,
-      IConfigurationAnnotation bc,
-      IConfigurationAnnotation ac,
-      IConfigurationAnnotation bm,
-      IConfigurationAnnotation am) {
+      @Nullable IConfigurationAnnotation bs,
+      @Nullable IConfigurationAnnotation as,
+      @Nullable IConfigurationAnnotation bt,
+      @Nullable IConfigurationAnnotation at,
+      @Nullable IConfigurationAnnotation bg,
+      @Nullable IConfigurationAnnotation ag,
+      @Nullable IConfigurationAnnotation bc,
+      @Nullable IConfigurationAnnotation ac,
+      @Nullable IConfigurationAnnotation bm,
+      @Nullable IConfigurationAnnotation am) {
     ConfigurationAnnotation result = new ConfigurationAnnotation();
 
     if (bs != null) {
@@ -306,7 +313,7 @@ && isAnnotationPresent(annotationFinder, cls, ITestAnnotation.class)) {
     return vResult.values().toArray(new ITestNGMethod[0]);
   }
 
-  public static <A extends Annotation> A findAnnotationSuperClasses(
+  public static <A extends Annotation> @Nullable A findAnnotationSuperClasses(
       Class<A> annotationClass, Class<?> parameterClass) {
     Class<?> c = parameterClass;
     while (c != null) {

testng-core/src/main/java/org/testng/internal/annotations/BaseAnnotation.java

@@ -2,30 +2,31 @@
 
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
+import org.jspecify.annotations.Nullable;
 
 public class BaseAnnotation {
 
-  private Class<?> m_testClass;
-  private Method m_method;
-  private Constructor m_constructor;
+  private @Nullable Class<?> m_testClass;
+  private @Nullable Method m_method;
+  private @Nullable Constructor m_constructor;
 
-  public Constructor getConstructor() {
+  public @Nullable Constructor getConstructor() {
     return m_constructor;
   }
 
   public void setConstructor(Constructor constructor) {
     m_constructor = constructor;
   }
 
-  public Method getMethod() {
+  public @Nullable Method getMethod() {
     return m_method;
   }
 
   public void setMethod(Method method) {
     m_method = method;
   }
 
-  public Class<?> getTestClass() {
+  public @Nullable Class<?> getTestClass() {
     return m_testClass;
   }
 

testng-core/src/main/java/org/testng/internal/annotations/BaseBeforeAfter.java

@@ -1,22 +1,24 @@
 package org.testng.internal.annotations;
 
+import org.jspecify.annotations.Nullable;
+
 public class BaseBeforeAfter extends TestOrConfiguration implements IBaseBeforeAfter {
 
   private boolean m_alwaysRun = false;
   private boolean m_inheritGroups = true;
   private String[] m_beforeGroups = {};
   private String[] m_afterGroups = {};
-  private String m_description;
+  private @Nullable String m_description;
 
   /** @return the description */
   @Override
-  public String getDescription() {
+  public @Nullable String getDescription() {
     return m_description;
   }
 
   /** @param description the description to set */
   @Override
-  public void setDescription(String description) {
+  public void setDescription(@Nullable String description) {
     m_description = description;
   }
 

testng-core/src/main/java/org/testng/internal/annotations/DataProviderAnnotation.java

@@ -1,17 +1,19 @@
 package org.testng.internal.annotations;
 
+import java.util.Collections;
 import java.util.List;
 import org.testng.IRetryDataProvider;
 import org.testng.annotations.IDataProviderAnnotation;
 
 /** An implementation of IDataProvider. */
 public class DataProviderAnnotation extends BaseAnnotation implements IDataProviderAnnotation {
 
-  private String m_name;
+  private String m_name = "";
   private boolean m_parallel;
-  private List<Integer> m_indices;
+  private List<Integer> m_indices = Collections.emptyList();
   private boolean m_bubbleUpFailures = false;
-  private Class<? extends IRetryDataProvider> retryUsing;
+  private Class<? extends IRetryDataProvider> retryUsing =
+      IRetryDataProvider.DisableDataProviderRetries.class;
 
   private boolean cachedDataForTestRetries = true;
 

testng-core/src/main/java/org/testng/internal/annotations/DefaultAnnotationTransformer.java

@@ -2,6 +2,7 @@
 
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
+import org.jspecify.annotations.Nullable;
 import org.testng.IAnnotationTransformer;
 import org.testng.annotations.ITestAnnotation;
 
@@ -15,7 +16,11 @@ public void transform(
 
   @Override
   public void transform(
-      ITestAnnotation annotation, Class testClass, Constructor cons, Method tm, Class<?> clazz) {
+      ITestAnnotation annotation,
+      @Nullable Class testClass,
+      @Nullable Constructor cons,
+      @Nullable Method tm,
+      @Nullable Class<?> clazz) {
     super.transform(annotation, testClass, cons, tm, clazz);
   }
 }

testng-core/src/main/java/org/testng/internal/annotations/FactoryAnnotation.java

@@ -1,17 +1,18 @@
 package org.testng.internal.annotations;
 
 import java.util.List;
+import org.jspecify.annotations.Nullable;
 import org.testng.annotations.IFactoryAnnotation;
 import org.testng.annotations.Lazy;
 
 /** An implementation of IFactory */
 public class FactoryAnnotation extends BaseAnnotation implements IFactoryAnnotation {
 
-  private String m_dataProvider = null;
-  private Class<?> m_dataProviderClass;
-  private String m_dataProviderDynamicClass;
+  private String m_dataProvider = "";
+  private @Nullable Class<?> m_dataProviderClass;
+  private String m_dataProviderDynamicClass = "";
   private boolean m_enabled = true;
-  private List<Integer> m_indices;
+  private @Nullable List<Integer> m_indices;
   private Lazy m_lazy = Lazy.UNSET;
 
   @Override
@@ -24,12 +25,12 @@ public void setDataProvider(String dataProvider) {
     m_dataProvider = dataProvider;
   }
 
-  public void setDataProviderClass(Class<?> dataProviderClass) {
+  public void setDataProviderClass(@Nullable Class<?> dataProviderClass) {
     m_dataProviderClass = dataProviderClass;
   }
 
   @Override
-  public Class<?> getDataProviderClass() {
+  public @Nullable Class<?> getDataProviderClass() {
     return m_dataProviderClass;
   }
 
@@ -54,7 +55,7 @@ public void setEnabled(boolean enabled) {
   }
 
   @Override
-  public List<Integer> getIndices() {
+  public @Nullable List<Integer> getIndices() {
     return m_indices;
   }
 
@@ -69,7 +70,7 @@ public Lazy getLazy() {
   }
 
   @Override
-  public void setLazy(Lazy lazy) {
+  public void setLazy(@Nullable Lazy lazy) {
     m_lazy = lazy == null ? Lazy.UNSET : lazy;
   }
 }

testng-core/src/main/java/org/testng/internal/annotations/IAnnotationTransformer.java

@@ -2,17 +2,18 @@
 
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
+import org.jspecify.annotations.Nullable;
 import org.testng.annotations.ITestAnnotation;
 
 /** For backward compatibility. */
 public interface IAnnotationTransformer extends org.testng.IAnnotationTransformer {
 
   default void transform(
       ITestAnnotation annotation,
-      Class testClass,
-      Constructor testConstructor,
-      Method testMethod,
-      Class<?> occurringClazz) {
+      @Nullable Class testClass,
+      @Nullable Constructor testConstructor,
+      @Nullable Method testMethod,
+      @Nullable Class<?> occurringClazz) {
     // not implemented
   }
 }

testng-core/src/main/java/org/testng/internal/annotations/IBaseBeforeAfter.java

@@ -1,5 +1,6 @@
 package org.testng.internal.annotations;
 
+import org.jspecify.annotations.Nullable;
 import org.testng.annotations.ITestOrConfiguration;
 
 /** Base interface for IBeforeSuite, IAfterSuite, etc... */
@@ -46,6 +47,7 @@ public interface IBaseBeforeAfter extends ITestOrConfiguration {
    * The description for this method. The string used will appear in the HTML report and also on
    * standard output if verbose > 2.
    */
+  @Nullable
   String getDescription();
 
   default boolean ignoreFailure() {