Support nullable type annotations with a flag.

Chang-Eric · Dagger Team · commit 4bedb4b6417e · 2026-06-17T11:42:15.000-07:00
Fixes #5165. RELNOTES=Support nullable type annotations when using the flag `-Adagger.nullableTypeAnnotations=enabled`. Fixes #5165. PiperOrigin-RevId: 933839515
diff --git a/dagger-compiler/BUILD b/dagger-compiler/BUILD
@@ -52,6 +52,7 @@ gen_maven_artifact(
         "//dagger-compiler/main/java/dagger/internal/codegen/validation",
         "//dagger-compiler/main/java/dagger/internal/codegen/writing",
         "//dagger-compiler/main/java/dagger/internal/codegen/xprocessing",
+        "//dagger-compiler/main/java/dagger/internal/codegen/xprocessing:nullability",
         "//dagger-compiler/main/java/dagger/internal/codegen/xprocessing:xpoet",
     ],
     artifact_target_maven_deps = [
diff --git a/dagger-compiler/main/java/dagger/internal/codegen/binding/BUILD b/dagger-compiler/main/java/dagger/internal/codegen/binding/BUILD
@@ -30,6 +30,7 @@ java_library(
         "//dagger-compiler/main/java/dagger/internal/codegen/kotlin",
         "//dagger-compiler/main/java/dagger/internal/codegen/model",
         "//dagger-compiler/main/java/dagger/internal/codegen/xprocessing",
+        "//dagger-compiler/main/java/dagger/internal/codegen/xprocessing:nullability",
         "//dagger-compiler/main/java/dagger/internal/codegen/xprocessing:xpoet",
         "//dagger-runtime/main/java/dagger:core",
         "//dagger-spi",
diff --git a/dagger-compiler/main/java/dagger/internal/codegen/compileroption/CompilerOptions.java b/dagger-compiler/main/java/dagger/internal/codegen/compileroption/CompilerOptions.java
@@ -16,7 +16,9 @@
 
 package dagger.internal.codegen.compileroption;
 
+import androidx.room3.compiler.processing.XProcessingEnv;
 import androidx.room3.compiler.processing.XTypeElement;
+import com.google.common.base.Ascii;
 import javax.tools.Diagnostic;
 
 /** A collection of options that dictate how the compiler will run. */
@@ -168,4 +170,34 @@ public int keysPerComponentShard(XTypeElement component) {
    * boundaries at compile time (for Maps) and runtime (for Sets).
    */
   public abstract boolean mapMultibindingDuplicateDetectionFix();
+
+  /**
+   * Returns {@code true} if Dagger should also look for nullable type annotations.
+   *
+   * Note that when disabled, Dagger doesn't disallow usage of nullable type annotations. Instead,
+   * the behavior is simply that Dagger does not look for them, so types marked with nullable type
+   * annotations may appear to be non-nullable.
+   */
+  public abstract boolean nullableTypeAnnotations();
+
+  /**
+   * Returns {@code true} if Dagger should also look for nullable type annotations.
+   *
+   * @deprecated use {@link CompilerOptions#nullableTypeAnnotations()}. This method should only be
+   *     used for legacy code which requires accessing this flag from static methods that don't
+   *     easily have access to an instance of {@link CompilerOptions}.
+   */
+  @Deprecated
+  public static boolean nullableTypeAnnotations(XProcessingEnv processingEnv) {
+    String optionName =
+        ProcessingEnvironmentCompilerOptions.Feature.NULLABLE_TYPE_ANNOTATIONS.toString();
+    String defaultValue =
+        ProcessingEnvironmentCompilerOptions.Feature.NULLABLE_TYPE_ANNOTATIONS
+            .defaultValue().name();
+    String optionValue =
+        processingEnv.getOptions().containsKey(optionName)
+            ? processingEnv.getOptions().get(optionName)
+            : defaultValue;
+    return Ascii.equalsIgnoreCase(optionValue, FeatureStatus.ENABLED.name());
+  }
 }
diff --git a/dagger-compiler/main/java/dagger/internal/codegen/compileroption/ProcessingEnvironmentCompilerOptions.java b/dagger-compiler/main/java/dagger/internal/codegen/compileroption/ProcessingEnvironmentCompilerOptions.java
@@ -32,6 +32,7 @@
 import static dagger.internal.codegen.compileroption.ProcessingEnvironmentCompilerOptions.Feature.IGNORE_PROVISION_KEY_WILDCARDS;
 import static dagger.internal.codegen.compileroption.ProcessingEnvironmentCompilerOptions.Feature.INCLUDE_STACKTRACE_WITH_DEFERRED_ERROR_MESSAGES;
 import static dagger.internal.codegen.compileroption.ProcessingEnvironmentCompilerOptions.Feature.MAP_MULTIBINDING_DUPLICATE_DETECTION_FIX;
+import static dagger.internal.codegen.compileroption.ProcessingEnvironmentCompilerOptions.Feature.NULLABLE_TYPE_ANNOTATIONS;
 import static dagger.internal.codegen.compileroption.ProcessingEnvironmentCompilerOptions.Feature.PLUGINS_VISIT_FULL_BINDING_GRAPHS;
 import static dagger.internal.codegen.compileroption.ProcessingEnvironmentCompilerOptions.Feature.STRICT_MULTIBINDING_VALIDATION;
 import static dagger.internal.codegen.compileroption.ProcessingEnvironmentCompilerOptions.Feature.STRICT_SUPERFICIAL_VALIDATION;
@@ -216,6 +217,11 @@ public boolean mapMultibindingDuplicateDetectionFix() {
     return isEnabled(MAP_MULTIBINDING_DUPLICATE_DETECTION_FIX);
   }
 
+  @Override
+  public boolean nullableTypeAnnotations() {
+    return isEnabled(NULLABLE_TYPE_ANNOTATIONS);
+  }
+
   @Override
   public int keysPerComponentShard(XTypeElement component) {
     if (options.containsKey(KEYS_PER_COMPONENT_SHARD)) {
@@ -357,7 +363,9 @@ enum Feature implements EnumOption<FeatureStatus> {
 
     VALIDATE_TRANSITIVE_COMPONENT_DEPENDENCIES(ENABLED),
 
-    MAP_MULTIBINDING_DUPLICATE_DETECTION_FIX(DISABLED);
+    MAP_MULTIBINDING_DUPLICATE_DETECTION_FIX(DISABLED),
+
+    NULLABLE_TYPE_ANNOTATIONS;
 
     final FeatureStatus defaultValue;
 
diff --git a/dagger-compiler/main/java/dagger/internal/codegen/javac/JavacPluginCompilerOptions.java b/dagger-compiler/main/java/dagger/internal/codegen/javac/JavacPluginCompilerOptions.java
@@ -145,4 +145,9 @@ public boolean ignoreProvisionKeyWildcards() {
   public boolean mapMultibindingDuplicateDetectionFix() {
     return false;
   }
+
+  @Override
+  public boolean nullableTypeAnnotations() {
+    return false;
+  }
 }
diff --git a/dagger-compiler/main/java/dagger/internal/codegen/validation/BUILD b/dagger-compiler/main/java/dagger/internal/codegen/validation/BUILD
@@ -31,6 +31,7 @@ java_library(
         "//dagger-compiler/main/java/dagger/internal/codegen/kotlin",
         "//dagger-compiler/main/java/dagger/internal/codegen/model",
         "//dagger-compiler/main/java/dagger/internal/codegen/xprocessing",
+        "//dagger-compiler/main/java/dagger/internal/codegen/xprocessing:nullability",
         "//dagger-runtime/main/java/dagger:core",
         "//dagger-spi",
         "//third_party/java/auto:value",
diff --git a/dagger-compiler/main/java/dagger/internal/codegen/writing/BUILD b/dagger-compiler/main/java/dagger/internal/codegen/writing/BUILD
@@ -30,6 +30,7 @@ java_library(
         "//dagger-compiler/main/java/dagger/internal/codegen/compileroption",
         "//dagger-compiler/main/java/dagger/internal/codegen/model",
         "//dagger-compiler/main/java/dagger/internal/codegen/xprocessing",
+        "//dagger-compiler/main/java/dagger/internal/codegen/xprocessing:nullability",
         "//dagger-compiler/main/java/dagger/internal/codegen/xprocessing:xpoet",
         "//dagger-runtime/main/java/dagger:core",
         "//dagger-spi",
diff --git a/dagger-compiler/main/java/dagger/internal/codegen/xprocessing/BUILD b/dagger-compiler/main/java/dagger/internal/codegen/xprocessing/BUILD
@@ -20,6 +20,10 @@ load("//tools:bazel_compat.bzl", "compat_kt_jvm_library")
 
 package(default_visibility = ["//dagger-compiler:internal"])
 
+NULLABILITY_SRCS = [
+    "Nullability.java",
+]
+
 XPOET_SRCS = [
     "Accessibility.java",
     "NullableTypeNames.java",
@@ -33,10 +37,25 @@ XPOET_SRCS = [
     "XTypeSpecs.java",
 ]
 
+java_library(
+    name = "nullability",
+    srcs = NULLABILITY_SRCS,
+    deps = [
+        ":xprocessing",
+        "//dagger-compiler/main/java/dagger/internal/codegen/compileroption",
+        "//dagger-spi",
+        "//third_party/java/auto:value",
+        "//third_party/java/guava/base",
+        "//third_party/java/guava/collect",
+        "//third_party/java/javapoet",
+    ],
+)
+
 java_library(
     name = "xpoet",
     srcs = XPOET_SRCS,
     deps = [
+        ":nullability",
         ":xprocessing",
         "//dagger-compiler/main/java/dagger/internal/codegen/compileroption",
         "//dagger-spi",
@@ -57,7 +76,7 @@ compat_kt_jvm_library(
             "*.java",
             "*.kt",
         ],
-        exclude = XPOET_SRCS,
+        exclude = XPOET_SRCS + NULLABILITY_SRCS,
     ),
     exports = [
         ":xprocessing-lib",
diff --git a/dagger-compiler/main/java/dagger/internal/codegen/xprocessing/Nullability.java b/dagger-compiler/main/java/dagger/internal/codegen/xprocessing/Nullability.java
@@ -18,6 +18,7 @@
 
 import static androidx.room3.compiler.processing.XElementKt.isMethod;
 import static androidx.room3.compiler.processing.XElementKt.isVariableElement;
+import static androidx.room3.compiler.processing.compat.XConverters.getProcessingEnv;
 import static dagger.internal.codegen.extension.DaggerStreams.toImmutableList;
 import static dagger.internal.codegen.extension.DaggerStreams.toImmutableSet;
 import static dagger.internal.codegen.xprocessing.XElements.asMethod;
@@ -36,6 +37,7 @@
 import com.squareup.javapoet.AnnotationSpec;
 import com.squareup.javapoet.ParameterizedTypeName;
 import com.squareup.javapoet.TypeName;
+import dagger.internal.codegen.compileroption.CompilerOptions;
 import java.util.Optional;
 
 /**
@@ -57,8 +59,12 @@ public abstract class Nullability {
   public static Nullability of(XElement element) {
     ImmutableSet<XClassName> nonTypeUseNullableAnnotations = getNullableAnnotations(element);
     Optional<XType> type = getType(element);
-    ImmutableSet<XClassName> typeUseNullableAnnotations =
-    ImmutableSet.of();
+    ImmutableSet<XClassName> typeUseNullableAnnotations;
+    if (CompilerOptions.nullableTypeAnnotations(getProcessingEnv(element))) {
+      typeUseNullableAnnotations = type.map(Nullability::getNullableAnnotations).orElse(ImmutableSet.of());
+    } else {
+      typeUseNullableAnnotations = ImmutableSet.of();
+    }
     boolean isKotlinTypeNullable =
         // Note: Technically, it isn't possible for Java sources to have nullable types like in
         // Kotlin sources, but for some reason KSP treats certain types as nullable if they have a
diff --git a/javatests/dagger/functional/jdk8/BUILD b/javatests/dagger/functional/jdk8/BUILD
@@ -64,3 +64,27 @@ GenJavaTests(
         "//third_party/java/truth",
     ],
 )
+
+GenJavaLibrary(
+    name = "type_use_nullability_classes",
+    srcs = ["TypeUseNullabilityClasses.java"],
+    javacopts = DOCLINT_HTML_AND_SYNTAX,
+    deps = [
+        "//third_party/java/dagger",
+    ],
+)
+
+# TODO(b/203233586): Replace with GenJavaTest
+GenJavaTests(
+    name = "TypeUseNullabilityTest",
+    srcs = ["TypeUseNullabilityTest.java"],
+    gen_library_deps = [":type_use_nullability_classes"],
+    javacopts = DOCLINT_HTML_AND_SYNTAX + ["-Adagger.nullableTypeAnnotations=ENABLED"],
+    deps = [
+        "//third_party/java/dagger",
+        "//third_party/java/guava/base",
+        "//third_party/java/guava/collect",
+        "//third_party/java/junit",
+        "//third_party/java/truth",
+    ],
+)
diff --git a/javatests/dagger/functional/jdk8/TypeUseNullabilityClasses.java b/javatests/dagger/functional/jdk8/TypeUseNullabilityClasses.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2026 The Dagger Authors.
+ *
+ * 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.
+ */
+
+package dagger.functional.jdk8;
+
+import static java.lang.annotation.ElementType.TYPE_USE;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+import javax.inject.Inject;
+
+/**
+ * This class is compiled separately from the test in order to test nullability across compilation
+ * boundaries.
+ */
+final class TypeUseNullabilityClasses {
+
+  static final String EXPECTED_STRING = "foo";
+  static final Integer EXPECTED_INTEGER = 123;
+
+  static final class NullFoo {
+    final Integer nullableInteger;
+
+    @Inject
+    NullFoo(@TypeUse.Nullable Integer nullableInteger) {
+      this.nullableInteger = nullableInteger;
+    }
+
+    @Inject @TypeUse.Nullable Integer nullableIntegerField;
+
+    Integer nullableMethodInjectedField;
+
+    @Inject
+    void inject(@TypeUse.Nullable Integer nullableMethodInjectedField) {
+      this.nullableMethodInjectedField = nullableMethodInjectedField;
+    }
+  }
+
+  static final class GenericFoo<T> {
+    T t;
+
+    GenericFoo(T t) {
+      this.t = t;
+    }
+  }
+
+  static final class GenericBar<T> {
+    @Inject @TypeUse.Nullable T t;
+  }
+
+  static class TypeUse {
+    @Target(TYPE_USE)
+    @Retention(RUNTIME)
+    @interface Nullable {}
+
+    private TypeUse() {}
+  }
+
+  private TypeUseNullabilityClasses() {}
+}
diff --git a/javatests/dagger/functional/jdk8/TypeUseNullabilityTest.java b/javatests/dagger/functional/jdk8/TypeUseNullabilityTest.java

Original file line number	Diff line number	Diff line change
`@@ -145,4 +145,9 @@ public boolean ignoreProvisionKeyWildcards() {`
`145`	`145`	`public boolean mapMultibindingDuplicateDetectionFix() {`
`146`	`146`	`return false;`
`147`	`147`	`}`
	`148`	`+`
	`149`	`+ @Override`
	`150`	`+ public boolean nullableTypeAnnotations() {`
	`151`	`+ return false;`
	`152`	`+ }`
`148`	`153`	`}`