Support @NullMarked on modules

jdk-recent-unit-tests/build.gradle

@@ -41,6 +41,8 @@ dependencies {
     }
     testImplementation deps.test.jsr305Annotations
     testModulePath deps.test.cfQual
+    testModulePath deps.build.jspecify
+    testModulePath project(":test-java-module")
 }
 
 tasks.withType(Test).configureEach { test ->
@@ -64,4 +66,6 @@ tasks.getByName('test').configure {
     onlyIf {
         deps.versions.errorProneApi == deps.versions.errorProneLatest
     }
+    // we need this since we don't have an implementation / api dependence on test-java-module
+    dependsOn ':test-java-module:jar'
 }

jdk-recent-unit-tests/src/test/java/com/uber/nullaway/jdk17/ModuleInfoTests.java

@@ -44,4 +44,88 @@ public void testModuleInfo() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void nullmarkedModule() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "module-info.java",
+            "import org.jspecify.annotations.NullMarked;",
+            "@NullMarked",
+            "module com.example.myapp {",
+            "    exports com.example.myapp;",
+            "    requires java.base;",
+            "    requires org.jspecify;",
+            "}")
+        .addSourceLines(
+            "com/example/myapp/Test.java",
+            "package com.example.myapp;",
+            "public class Test {",
+            "  public static void main(String[] args) {",
+            "    String s = null;",
+            "    // BUG: Diagnostic contains: dereferenced expression s is @Nullable",
+            "    s.hashCode();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void nullUnmarkedPackageInNullMarkedModule() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "module-info.java",
+            "import org.jspecify.annotations.NullMarked;",
+            "@NullMarked",
+            "module com.example.myapp {",
+            "    exports com.example.myapp;",
+            "    requires java.base;",
+            "    requires org.jspecify;",
+            "}")
+        .addSourceLines(
+            "com/example/myapp/package-info.java",
+            "@NullUnmarked package com.example.myapp;",
+            "import org.jspecify.annotations.NullUnmarked;")
+        .addSourceLines(
+            "com/example/myapp/Test.java",
+            "package com.example.myapp;",
+            "public class Test {",
+            "  public static void main(String[] args) {",
+            "    String s = null;",
+            "    // no error since @NullUnmarked is in effect",
+            "    s.hashCode();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void fromBytecode() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "module-info.java",
+            "import org.jspecify.annotations.NullMarked;",
+            "@NullMarked",
+            "module com.example.myapp {",
+            "    requires java.base;",
+            "    requires org.jspecify;",
+            "    requires com.uber.test.java.module;",
+            "}")
+        .addSourceLines(
+            "Test.java",
+            "import org.jspecify.annotations.NullMarked;",
+            "import com.example.nullmarked.NullMarkedFromModule;",
+            "import com.example.nullunmarked.NullUnmarkedFromPackage;",
+            "@NullMarked",
+            "class Test {",
+            "  void testPositive() {",
+            "    // BUG: Diagnostic contains: passing @Nullable parameter",
+            "    NullMarkedFromModule.takesNonNull(null);",
+            "  }",
+            "  void testNegative() {",
+            "    NullUnmarkedFromPackage.takesAny(null);",
+            "  }",
+            "}")
+        .doTest();
+  }
 }

nullaway/src/main/java/com/uber/nullaway/CodeAnnotationInfo.java

@@ -71,7 +71,7 @@ public static CodeAnnotationInfo instance(Context context) {
   /**
    * Checks if a symbol comes from an annotated package, as determined by either configuration flags
    * (e.g. {@code -XepOpt:NullAway::AnnotatedPackages}) or package level annotations (e.g. {@code
-   * org.jspecify.annotations.NullMarked}).
+   * org.jspecify.annotations.NullMarked}) or module level annotations.
    *
    * @param outermostClassSymbol symbol for class (must be an outermost class)
    * @param config NullAway config
@@ -84,9 +84,7 @@ private static boolean fromAnnotatedPackage(
     String className = outermostClassSymbol.getQualifiedName().toString();
     Symbol.PackageSymbol enclosingPackage = ASTHelpers.enclosingPackage(outermostClassSymbol);
     if (!config.fromExplicitlyAnnotatedPackage(className)
-        && !(enclosingPackage != null
-            && hasDirectAnnotationWithSimpleName(
-                enclosingPackage, NullabilityUtil.NULLMARKED_SIMPLE_NAME))) {
+        && !(enclosingPackage != null && explicitlyNullMarkedPackageOrModule(enclosingPackage))) {
       // By default, unknown code is unannotated unless @NullMarked or configured as annotated by
       // package name
       return false;
@@ -105,6 +103,18 @@ && hasDirectAnnotationWithSimpleName(
     return true;
   }
 
+  private static boolean explicitlyNullMarkedPackageOrModule(
+      Symbol.PackageSymbol enclosingPackage) {
+    if (hasDirectAnnotationWithSimpleName(
+        enclosingPackage, NullabilityUtil.NULLMARKED_SIMPLE_NAME)) {
+      return true;
+    }
+    Symbol enclosingModule = enclosingPackage.getEnclosingElement();
+    return enclosingModule != null
+        && hasDirectAnnotationWithSimpleName(
+            enclosingModule, NullabilityUtil.NULLMARKED_SIMPLE_NAME);
+  }
+
   /**
    * Check if a symbol comes from generated code.
    *

settings.gradle

@@ -17,6 +17,7 @@ include ':sample-library-model'
 include ':sample'
 include ':test-java-lib'
 include ':test-java-lib-lombok'
+include ':test-java-module'
 include ':test-library-models'
 include ':jar-infer:android-jarinfer-models-sdk28'
 include ':jar-infer:android-jarinfer-models-sdk29'

test-java-module/build.gradle

@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2025. Uber Technologies
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+plugins {
+    id "java-library"
+}
+
+dependencies {
+    implementation deps.build.jspecify
+}

test-java-module/src/main/java/com/example/nullmarked/NullMarkedFromModule.java

@@ -0,0 +1,6 @@
+package com.example.nullmarked;
+
+public class NullMarkedFromModule {
+
+  public static void takesNonNull(Object o) {}
+}

test-java-module/src/main/java/com/example/nullunmarked/NullUnmarkedFromPackage.java

@@ -0,0 +1,6 @@
+package com.example.nullunmarked;
+
+public class NullUnmarkedFromPackage {
+
+  public static void takesAny(Object o) {}
+}

test-java-module/src/main/java/com/example/nullunmarked/package-info.java

@@ -0,0 +1,4 @@
+@NullUnmarked
+package com.example.nullunmarked;
+
+import org.jspecify.annotations.NullUnmarked;

test-java-module/src/main/java/module-info.java

@@ -0,0 +1,10 @@
+import org.jspecify.annotations.NullMarked;
+
+@NullMarked
+module com.uber.test.java.module {
+  requires java.base;
+  requires static org.jspecify;
+
+  exports com.example.nullmarked;
+  exports com.example.nullunmarked;
+}