pkl-config-java: Migrate nullness to jSpecify

pkl-config-java/gradle.lockfile

@@ -22,13 +22,30 @@ com.github.ajalt.mordant:mordant-markdown-jvm:3.0.1=pklCodegenJava
 com.github.ajalt.mordant:mordant-markdown:3.0.1=pklCodegenJava
 com.github.ajalt.mordant:mordant:3.0.1=pklCodegenJava
 com.github.ben-manes.caffeine:caffeine:2.9.3=swiftExportClasspathResolvable
+com.github.ben-manes.caffeine:caffeine:3.0.5=annotationProcessor,testAnnotationProcessor
+com.github.kevinstern:software-and-algorithms:1.0=annotationProcessor,testAnnotationProcessor
+com.google.auto.service:auto-service-annotations:1.0.1=annotationProcessor,testAnnotationProcessor
+com.google.auto.value:auto-value-annotations:1.9=annotationProcessor,testAnnotationProcessor
+com.google.auto:auto-common:1.2.2=annotationProcessor,testAnnotationProcessor
+com.google.errorprone:error_prone_annotation:2.48.0=annotationProcessor,testAnnotationProcessor
 com.google.errorprone:error_prone_annotations:2.28.0=swiftExportClasspathResolvable
+com.google.errorprone:error_prone_annotations:2.48.0=annotationProcessor,testAnnotationProcessor
+com.google.errorprone:error_prone_check_api:2.48.0=annotationProcessor,testAnnotationProcessor
+com.google.errorprone:error_prone_core:2.48.0=annotationProcessor,testAnnotationProcessor
+com.google.googlejavaformat:google-java-format:1.34.1=annotationProcessor,testAnnotationProcessor
+com.google.guava:failureaccess:1.0.3=annotationProcessor,testAnnotationProcessor
+com.google.guava:guava:33.5.0-jre=annotationProcessor,testAnnotationProcessor
+com.google.guava:listenablefuture:9999.0-empty-to-avoid-conflict-with-guava=annotationProcessor,testAnnotationProcessor
+com.google.j2objc:j2objc-annotations:3.1=annotationProcessor,testAnnotationProcessor
+com.google.protobuf:protobuf-java:4.33.2=annotationProcessor,testAnnotationProcessor
 com.palantir.javapoet:javapoet:0.14.0=pklCodegenJava
-io.github.java-diff-utils:java-diff-utils:4.12=kotlinInternalAbiValidation
+com.uber.nullaway:nullaway:0.13.1=annotationProcessor,testAnnotationProcessor
+io.github.eisop:dataflow-errorprone:3.41.0-eisop1=annotationProcessor,testAnnotationProcessor
+io.github.java-diff-utils:java-diff-utils:4.12=annotationProcessor,kotlinInternalAbiValidation,testAnnotationProcessor
 io.leangen.geantyref:geantyref:1.3.16=compileClasspath,runtimeClasspath,testCompileClasspath,testRuntimeClasspath
 io.opentelemetry:opentelemetry-api:1.41.0=swiftExportClasspathResolvable
 io.opentelemetry:opentelemetry-context:1.41.0=swiftExportClasspathResolvable
-javax.inject:javax.inject:1=testCompileClasspath,testRuntimeClasspath
+javax.inject:javax.inject:1=annotationProcessor,testAnnotationProcessor,testCompileClasspath,testRuntimeClasspath
 net.bytebuddy:byte-buddy:1.18.3=testCompileClasspath,testRuntimeClasspath
 net.java.dev.jna:jna:5.14.0=pklCodegenJava
 org.apiguardian:apiguardian-api:1.1.2=testCompileClasspath
@@ -38,6 +55,8 @@ org.bouncycastle:bcpkix-jdk18on:1.80=kotlinBouncyCastleConfiguration
 org.bouncycastle:bcprov-jdk18on:1.80=kotlinBouncyCastleConfiguration
 org.bouncycastle:bcutil-jdk18on:1.80=kotlinBouncyCastleConfiguration
 org.checkerframework:checker-qual:3.43.0=swiftExportClasspathResolvable
+org.checkerframework:checker-qual:3.53.0=annotationProcessor,testAnnotationProcessor
+org.checkerframework:dataflow-nullaway:3.53.0=annotationProcessor,testAnnotationProcessor
 org.graalvm.polyglot:polyglot:25.0.1=pklCodegenJava,runtimeClasspath,testRuntimeClasspath
 org.graalvm.sdk:collections:25.0.1=pklCodegenJava,runtimeClasspath,testRuntimeClasspath
 org.graalvm.sdk:graal-sdk:25.0.1=pklCodegenJava,runtimeClasspath,testRuntimeClasspath
@@ -79,7 +98,7 @@ org.jetbrains.kotlinx:kotlinx-serialization-core:1.7.3=swiftExportClasspathResol
 org.jetbrains:annotations:13.0=kotlinBuildToolsApiClasspath,kotlinCompilerClasspath,kotlinCompilerPluginClasspathMain,kotlinCompilerPluginClasspathTest,kotlinInternalAbiValidation,kotlinKlibCommonizerClasspath,pklCodegenJava,swiftExportClasspathResolvable,testCompileClasspath,testRuntimeClasspath
 org.jetbrains:markdown-jvm:0.7.3=pklCodegenJava
 org.jetbrains:markdown:0.7.3=pklCodegenJava
-org.jspecify:jspecify:1.0.0=pklCodegenJava,runtimeClasspath,testCompileClasspath,testRuntimeClasspath
+org.jspecify:jspecify:1.0.0=annotationProcessor,compileClasspath,pklCodegenJava,runtimeClasspath,testAnnotationProcessor,testCompileClasspath,testRuntimeClasspath
 org.junit.jupiter:junit-jupiter-api:6.0.3=testCompileClasspath,testRuntimeClasspath
 org.junit.jupiter:junit-jupiter-engine:6.0.3=testRuntimeClasspath
 org.junit.jupiter:junit-jupiter-params:6.0.3=testCompileClasspath,testRuntimeClasspath
@@ -90,5 +109,6 @@ org.junit:junit-bom:6.0.3=testCompileClasspath,testRuntimeClasspath
 org.msgpack:msgpack-core:0.9.11=compileClasspath,pklCodegenJava,runtimeClasspath,testCompileClasspath,testRuntimeClasspath
 org.opentest4j:opentest4j:1.3.0=testCompileClasspath,testRuntimeClasspath
 org.organicdesign:Paguro:3.10.3=pklCodegenJava,runtimeClasspath,testRuntimeClasspath
+org.pcollections:pcollections:4.0.1=annotationProcessor,testAnnotationProcessor
 org.snakeyaml:snakeyaml-engine:2.10=pklCodegenJava,runtimeClasspath,testRuntimeClasspath
-empty=annotationProcessor,apiDependenciesMetadata,compileOnlyDependenciesMetadata,fatJar,firstPartySourcesJars,implementationDependenciesMetadata,intransitiveDependenciesMetadata,kotlinCompilerPluginClasspath,kotlinNativeCompilerPluginClasspath,kotlinScriptDefExtensions,shadow,signatures,sourcesJar,testAnnotationProcessor,testApiDependenciesMetadata,testCompileOnlyDependenciesMetadata,testImplementationDependenciesMetadata,testIntransitiveDependenciesMetadata,testKotlinScriptDefExtensions
+empty=apiDependenciesMetadata,compileOnlyDependenciesMetadata,fatJar,firstPartySourcesJars,implementationDependenciesMetadata,intransitiveDependenciesMetadata,kotlinCompilerPluginClasspath,kotlinNativeCompilerPluginClasspath,kotlinScriptDefExtensions,shadow,signatures,sourcesJar,testApiDependenciesMetadata,testCompileOnlyDependenciesMetadata,testImplementationDependenciesMetadata,testIntransitiveDependenciesMetadata,testKotlinScriptDefExtensions

pkl-config-java/pkl-config-java.gradle.kts

@@ -18,6 +18,7 @@ plugins {
   id("pklJavaLibrary")
   id("pklFatJar")
   id("pklPublishLibrary")
+  id("pklJSpecify")
   signing
 }
 

pkl-config-java/src/main/java/org/pkl/config/java/Config.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,7 @@
 import java.io.InputStream;
 import java.lang.reflect.Type;
 import java.util.Map;
+import org.jspecify.annotations.Nullable;
 import org.pkl.config.java.mapper.ConversionException;
 import org.pkl.config.java.mapper.ValueMapper;
 import org.pkl.core.Composite;
@@ -55,7 +56,7 @@ public interface Config {
    *
    * @throws ConversionException if the value cannot be converted to the given type
    */
-  <T> T as(Class<T> type);
+  <T extends @Nullable Object> T as(Class<T> type);
 
   /**
    * Converts this node's value to the given {@link Type}.
@@ -64,14 +65,14 @@ public interface Config {
    *
    * @throws ConversionException if the value cannot be converted to the given type
    */
-  <T> T as(Type type);
+  <T extends @Nullable Object> T as(Type type);
 
   /**
    * Converts this node's value to the given {@link JavaType}.
    *
    * @throws ConversionException if the value cannot be converted to the given type
    */
-  <T> T as(JavaType<T> type);
+  <T extends @Nullable Object> T as(JavaType<T> type);
 
   /**
    * Decode a config from the supplied byte array.

pkl-config-java/src/main/java/org/pkl/config/java/ConfigEvaluatorBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,14 +21,14 @@
 import java.util.List;
 import java.util.Map;
 import java.util.regex.Pattern;
+import org.jspecify.annotations.Nullable;
 import org.pkl.config.java.mapper.ValueMapperBuilder;
 import org.pkl.core.EvaluatorBuilder;
 import org.pkl.core.SecurityManager;
 import org.pkl.core.StackFrameTransformer;
 import org.pkl.core.http.HttpClient;
 import org.pkl.core.project.DeclaredDependencies;
 import org.pkl.core.project.Project;
-import org.pkl.core.util.Nullable;
 
 /** A builder for {@link ConfigEvaluator}s. */
 @SuppressWarnings({"UnusedReturnValue", "unused"})

pkl-config-java/src/main/java/org/pkl/config/java/JavaType.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,9 +18,9 @@
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.util.*;
+import org.jspecify.annotations.Nullable;
 import org.pkl.config.java.mapper.Types;
 import org.pkl.core.Pair;
-import org.pkl.core.util.Nullable;
 
 /**
  * Runtime representation of a possibly parameterized Java type. Factory methods are provided to

pkl-config-java/src/main/java/org/pkl/config/java/mapper/ClassRegistry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,10 +20,10 @@
 import java.util.HashSet;
 import java.util.Properties;
 import java.util.Set;
+import org.jspecify.annotations.Nullable;
 import org.pkl.config.java.InvalidMappingException;
 import org.pkl.core.PClassInfo;
 import org.pkl.core.util.IoUtils;
-import org.pkl.core.util.Nullable;
 
 /**
  * Describes mappings of Pkl class names to their corresponding Java classes.

pkl-config-java/src/main/java/org/pkl/config/java/mapper/ConversionException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,13 +15,15 @@
  */
 package org.pkl.config.java.mapper;
 
+import org.jspecify.annotations.Nullable;
+
 /** Thrown when a {@link ValueMapper} conversion fails. */
 public class ConversionException extends RuntimeException {
   public ConversionException(String message) {
     super(message);
   }
 
-  public ConversionException(String message, Throwable cause) {
+  public ConversionException(String message, @Nullable Throwable cause) {
     super(message, cause);
   }
 }

pkl-config-java/src/main/java/org/pkl/config/java/mapper/Converter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,14 +15,16 @@
  */
 package org.pkl.config.java.mapper;
 
+import org.jspecify.annotations.Nullable;
+
 /**
  * Converter for a particular source and target type.
  *
  * @param <S> the converter's source type
  * @param <T> the converter's target type
  */
 @FunctionalInterface
-public interface Converter<S, T> {
+public interface Converter<S, T extends @Nullable Object> {
   /**
    * Converts the given value. The given {@link ValueMapper} can be used to convert nested values of
    * composite values (objects, collections, etc.).

pkl-config-java/src/main/java/org/pkl/config/java/mapper/PCollectionToArray.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,8 +19,8 @@
 import java.lang.reflect.Type;
 import java.util.Collection;
 import java.util.Optional;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.PClassInfo;
-import org.pkl.core.util.Nullable;
 
 final class PCollectionToArray implements ConverterFactory {
   @Override

pkl-config-java/src/main/java/org/pkl/config/java/mapper/PCollectionToCollection.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,8 +23,8 @@
 import java.util.Collection;
 import java.util.Optional;
 import java.util.function.Function;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.PClassInfo;
-import org.pkl.core.util.Nullable;
 
 class PCollectionToCollection implements ConverterFactory {
   private static final Lookup lookup = MethodHandles.lookup();

pkl-config-java/src/main/java/org/pkl/config/java/mapper/PMapToMap.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,8 +24,8 @@
 import java.util.Optional;
 import java.util.Properties;
 import java.util.function.Function;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.PClassInfo;
-import org.pkl.core.util.Nullable;
 
 class PMapToMap implements ConverterFactory {
   private static final Lookup lookup = MethodHandles.lookup();

pkl-config-java/src/main/java/org/pkl/config/java/mapper/PObjectToDataObject.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,10 +22,10 @@
 import java.lang.invoke.MethodHandles.Lookup;
 import java.lang.reflect.*;
 import java.util.*;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.Composite;
 import org.pkl.core.PClassInfo;
 import org.pkl.core.PObject;
-import org.pkl.core.util.Nullable;
 
 public class PObjectToDataObject implements ConverterFactory {
   private static final Lookup lookup = MethodHandles.lookup();
@@ -156,7 +156,7 @@ private static class ConverterImpl<T> implements Converter<Composite, T> {
     private final MethodHandle constructorHandle;
     private final Collection<Tuple2<String, Type>> parameters;
     private final PClassInfo<Object>[] cachedPropertyTypes;
-    private final Converter<Object, T>[] cachedConverters;
+    private final @Nullable Converter<Object, T>[] cachedConverters;
 
     ConverterImpl(
         Type targetType,
@@ -172,7 +172,7 @@ private static class ConverterImpl<T> implements Converter<Composite, T> {
       Arrays.fill(cachedPropertyTypes, PClassInfo.Unavailable);
 
       @SuppressWarnings("unchecked")
-      Converter<Object, T>[] cachedConverters = new Converter[parameters.size()];
+      @Nullable Converter<Object, T>[] cachedConverters = new Converter[parameters.size()];
       this.cachedConverters = cachedConverters;
     }
 
@@ -203,8 +203,9 @@ public T convert(Composite value, ValueMapper valueMapper) {
             cachedPropertyTypes[i] = cachedPropertyType;
             cachedConverters[i] = valueMapper.getConverter(cachedPropertyType, param.second);
           }
-          assert cachedConverters[i] != null;
-          args[i] = cachedConverters[i].convert(property, valueMapper);
+          var cachedConverter = cachedConverters[i];
+          assert cachedConverter != null;
+          args[i] = cachedConverter.convert(property, valueMapper);
           i += 1;
         } catch (ConversionException e) {
           throw new ConversionException(

pkl-config-java/src/main/java/org/pkl/config/java/mapper/PPairToPair.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,9 +18,9 @@
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.util.Optional;
+import org.jspecify.annotations.Nullable;
 import org.pkl.core.PClassInfo;
 import org.pkl.core.Pair;
-import org.pkl.core.util.Nullable;
 
 final class PPairToPair implements ConverterFactory {
   @Override

pkl-config-java/src/main/java/org/pkl/config/java/mapper/PStringToEnum.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -46,12 +46,16 @@ private ConverterImpl(Class<?> enumType) {
       if (enumType == DataSizeUnit.class) {
         for (var value : values) {
           var unit = (DataSizeUnit) value;
-          enumValuesByName.put(CodeGeneratorUtils.toEnumConstantName(unit.getSymbol()), value);
+          var name = CodeGeneratorUtils.toEnumConstantName(unit.getSymbol());
+          assert name != null;
+          enumValuesByName.put(name, value);
         }
       } else if (enumType == DurationUnit.class) {
         for (var value : values) {
           var unit = (DurationUnit) value;
-          enumValuesByName.put(CodeGeneratorUtils.toEnumConstantName(unit.getSymbol()), value);
+          var name = CodeGeneratorUtils.toEnumConstantName(unit.getSymbol());
+          assert name != null;
+          enumValuesByName.put(name, value);
         }
       } else {
         for (Enum<?> value : values) {

pkl-config-java/src/main/java/org/pkl/config/java/mapper/Reflection.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,7 +20,7 @@
 import io.leangen.geantyref.CaptureType;
 import io.leangen.geantyref.GenericTypeReflector;
 import java.lang.reflect.*;
-import org.pkl.core.util.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * Reflection utilities for implementing {@link ConverterFactory}s. Mostly covers introspection of

pkl-config-java/src/main/java/org/pkl/config/java/mapper/Tuple2.java

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 package org.pkl.config.java.mapper;
 
 import java.util.Objects;
-import org.pkl.core.util.Nullable;
+import org.jspecify.annotations.Nullable;
 
 // avoid name clash with org.pkl.core.Pair
 final class Tuple2<S, T> {