[WIP] Better handling of Lombok configuration for @Nullable annotations

README.md

@@ -80,13 +80,13 @@ Unlike other annotation processors above, Lombok modifies the in-memory AST of t
 
 We do not particularly recommend using NullAway with Lombok. However, NullAway encodes some knowledge of common Lombok annotations and we do try for best-effort compatibility. In particular, common usages like `@lombok.Builder` and `@Data` classes should be supported.
 
-In order for NullAway to successfully detect Lombok generated code within the in-memory Java AST, the following configuration option must be passed to Lombok as part of an applicable `lombok.config` file:
+For the best compatibility with NullAway, add the following configuration options to an applicable `lombok.config` file:
 
 ```
-addLombokGeneratedAnnotation
+lombok.addLombokGeneratedAnnotation = true
+lombok.addNullAnnotations = <flavor>
 ```
-
-This causes Lombok to add `@lombok.Generated` to the methods/classes it generates. NullAway will ignore (i.e. not check) the implementation of this generated code, treating it as unannotated. 
+See the [Lombok configuration documentation](https://projectlombok.org/features/configuration) for more details.  The `addLombokGeneratedAnnotation` option causes Lombok to add `@lombok.Generated` to the methods/classes it generates.  NullAway will ignore (i.e. not check) the implementation of this generated code, treating it as unannotated.  The `addNullAnnotations` options causes Lombok to add nullability annotations to its generated code, which can remove certain NullAway false positives.  In particular, with this option enabled, Lombok adds a `@Nullable` annotation to the parameter of every generated `equals()` method, and then NullAway will not warn if a `@Nullable` argument is passed to such a method.  
 
 ## Code Example
 

gradle/dependencies.gradle

@@ -109,7 +109,7 @@ def test = [
     rxjava2                 : "io.reactivex.rxjava2:rxjava:2.1.2",
     commonsLang3            : "org.apache.commons:commons-lang3:3.8.1",
     commonsLang             : "commons-lang:commons-lang:2.6",
-    lombok                  : "org.projectlombok:lombok:1.18.24",
+    lombok                  : "org.projectlombok:lombok:1.18.30",
     springBeans             : "org.springframework:spring-beans:5.3.7",
     springContext           : "org.springframework:spring-context:5.3.7",
     grpcCore                : "io.grpc:grpc-core:1.15.1", // Should upgrade, but this matches our guava version

nullaway/src/main/java/com/uber/nullaway/handlers/LombokHandler.java

@@ -86,26 +86,4 @@ public Nullness onOverrideMethodReturnNullability(
     }
     return returnNullness;
   }
-
-  /**
-   * Mark the first argument of Lombok-generated {@code equals} methods as {@code @Nullable}, since
-   * Lombok does not generate the annotation.
-   */
-  @Override
-  public Nullness[] onOverrideMethodInvocationParametersNullability(
-      VisitorState state,
-      Symbol.MethodSymbol methodSymbol,
-      boolean isAnnotated,
-      Nullness[] argumentPositionNullness) {
-    if (ASTHelpers.hasAnnotation(methodSymbol, LOMBOK_GENERATED_ANNOTATION_NAME, state)) {
-      // We assume that Lombok-generated equals methods with a single argument override
-      // Object.equals and are not an overload.
-      if (methodSymbol.getSimpleName().contentEquals("equals")
-          && methodSymbol.params().size() == 1) {
-        // The parameter is not annotated with @Nullable, but it should be.
-        argumentPositionNullness[0] = Nullness.NULLABLE;
-      }
-    }
-    return argumentPositionNullness;
-  }
 }

test-java-lib-lombok/build.gradle

@@ -44,3 +44,8 @@ tasks.withType(JavaCompile) {
         "--add-opens=jdk.compiler/com.sun.tools.javac.jvm=ALL-UNNAMED"
     ]
 }
+
+// Needed so that compilation re-runs if the lombok.config is changed
+tasks.named('compileJava') {
+    inputs.file('lombok.config')
+}

test-java-lib-lombok/lombok.config

@@ -1,2 +1,3 @@
 config.stopBubbling = true
 lombok.addLombokGeneratedAnnotation = true
+lombok.addNullAnnotations = javax