feat(*): Migrate to JSpecify

.checkstyle/checkstyle.xml

@@ -101,7 +101,7 @@
 
     <!-- https://checkstyle.org/config_imports.html#IllegalImport -->
     <module name="IllegalImport">
-      <property name="illegalPkgs" value="sun, jdk, com.sun"/>
+      <property name="illegalPkgs" value="sun, jdk, com.sun, org.jetbrains.annotations"/>
     </module>
 
     <!-- https://checkstyle.org/config_coding.html#IllegalTokenText -->

build.gradle

@@ -17,7 +17,8 @@ indraSonatype {
 }
 
 dependencies {
-  compileOnlyApi libs.jetbrainsAnnotations
+  compileOnlyApi libs.jetbrainsAnnotations // keep to avoid breaking builds, will be removed for 2.0
+  compileOnlyApi libs.jspecify
   implementation gradleApi()
 
   testImplementation platform(libs.junit.bom)

gradle/libs.versions.toml

@@ -1,5 +1,5 @@
 [metadata]
-version = "1.0"
+format = { version = "1.1" }
 
 [versions]
 checkstyle = "10.18.2"
@@ -9,7 +9,8 @@ stylecheck = "0.2.1"
 errorprone = "2.30.0"
 
 [libraries]
-jetbrainsAnnotations = "org.jetbrains:annotations:25.0.0"
+jetbrainsAnnotations = { module = "org.jetbrains:annotations", version = "25.0.0" }
+jspecify = { module = "org.jspecify:jspecify", version = "1.0.0" }
 
 # test
 junit-bom = { module = "org.junit:junit-bom", version.ref = "junit" }

mammoth-test/build.gradle

@@ -3,7 +3,7 @@ description = "JUnit extensions for testing Gradle plugins"
 dependencies {
   api gradleApi()
   api gradleTestKit()
-  compileOnlyApi libs.jetbrainsAnnotations
+  compileOnlyApi libs.jspecify
   api platform(libs.junit.bom)
   api libs.junit.api
   implementation libs.junit.platformCommons

mammoth-test/src/main/java/net/kyori/mammoth/test/GradleFunctionalTestExtension.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of mammoth, licensed under the MIT License.
  *
- * Copyright (c) 2021-2024 KyoriPowered
+ * Copyright (c) 2021-2025 KyoriPowered
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -36,8 +36,9 @@
 import java.util.List;
 import java.util.Optional;
 import java.util.stream.Stream;
-import javax.annotation.Nullable;
 import org.gradle.util.GradleVersion;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.extension.Extension;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.TestTemplateInvocationContext;
@@ -47,6 +48,7 @@
 /**
  * An extension that can be applied to test methods to provide test template invocation context.
  */
+@NullMarked
 class GradleFunctionalTestExtension implements TestTemplateInvocationContextProvider {
   private static final int CURRENT_JVM;
 

mammoth-test/src/main/java/net/kyori/mammoth/test/TemplateInvocationExtensions.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of mammoth, licensed under the MIT License.
  *
- * Copyright (c) 2021-2022 KyoriPowered
+ * Copyright (c) 2021-2025 KyoriPowered
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -29,13 +29,15 @@
 import java.nio.file.Path;
 import java.nio.file.SimpleFileVisitor;
 import java.nio.file.attribute.BasicFileAttributes;
+import org.jspecify.annotations.NullMarked;
 import org.junit.jupiter.api.extension.AfterEachCallback;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.ParameterContext;
 import org.junit.jupiter.api.extension.ParameterResolutionException;
 import org.junit.jupiter.api.extension.ParameterResolver;
 
 // Template-specific context information
+@NullMarked
 class TemplateInvocationExtensions implements AfterEachCallback, ParameterResolver {
   private final TestContext context;
 

mammoth-test/src/main/java/net/kyori/mammoth/test/TestContext.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of mammoth, licensed under the MIT License.
  *
- * Copyright (c) 2021-2022 KyoriPowered
+ * Copyright (c) 2021-2025 KyoriPowered
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -37,7 +37,7 @@
 import java.util.regex.Pattern;
 import org.gradle.testkit.runner.BuildResult;
 import org.gradle.testkit.runner.GradleRunner;
-import org.jetbrains.annotations.NotNull;
+import org.jspecify.annotations.NullMarked;
 import org.junit.jupiter.api.Assertions;
 
 import static java.util.Objects.requireNonNull;
@@ -49,6 +49,7 @@
  *
  * @since 1.1.0
  */
+@NullMarked
 public final class TestContext {
   private static final Pattern LINE_ENDING = Pattern.compile("\r\n");
 
@@ -78,11 +79,11 @@ public final class TestContext {
    * @return the output directory
    * @since 1.1.0
    */
-  public @NotNull Path outputDirectory() {
+  public Path outputDirectory() {
     return this.outputDirectory;
   }
 
-  @NotNull String gradleVersion() {
+  String gradleVersion() {
     return this.gradleVersion;
   }
 
@@ -93,7 +94,7 @@ public final class TestContext {
    * @throws IOException if an error occurs writing the input file to disk
    * @since 1.1.0
    */
-  public void copyInput(final @NotNull String name) throws IOException {
+  public void copyInput(final String name) throws IOException {
     this.copyInput(name, name);
   }
 
@@ -105,7 +106,7 @@ public void copyInput(final @NotNull String name) throws IOException {
    * @throws IOException if an error occurs writing the input file to disk
    * @since 1.1.0
    */
-  public void copyInput(final @NotNull String fromName, final @NotNull String toName) throws IOException {
+  public void copyInput(final String fromName, final String toName) throws IOException {
     requireNonNull(fromName, "fromName");
     requireNonNull(toName, "toName");
     try (final InputStream is = this.resourceBase.getResourceAsStream(this.testName + "/in/" + fromName)) {
@@ -130,7 +131,7 @@ public void copyInput(final @NotNull String fromName, final @NotNull String toNa
    * @throws IOException if an error occurs writing the text
    * @since 1.2.0
    */
-  public void writeText(final @NotNull String destination, final @NotNull String text) throws IOException {
+  public void writeText(final String destination, final String text) throws IOException {
     requireNonNull(destination, "destination");
     requireNonNull(text, "text");
 
@@ -149,7 +150,7 @@ public void writeText(final @NotNull String destination, final @NotNull String t
    * @throws IOException if thrown while attempting to read the output file
    * @since 1.1.0
    */
-  public @NotNull String readOutput(final @NotNull String fileName) throws IOException {
+  public String readOutput(final String fileName) throws IOException {
     final StringBuilder builder = new StringBuilder();
     try (final BufferedReader reader = Files.newBufferedReader(this.outputDirectory.resolve(fileName), StandardCharsets.UTF_8)) {
       final char[] buffer = new char[8192];
@@ -169,7 +170,7 @@ public void writeText(final @NotNull String destination, final @NotNull String t
    * @throws IOException if an error occurs reading the text
    * @since 1.2.0
    */
-  public void assertOutputEqualsLiteral(final @NotNull String destination, final @NotNull String text) throws IOException {
+  public void assertOutputEqualsLiteral(final String destination, final String text) throws IOException {
     requireNonNull(destination, "destination");
     requireNonNull(text, "text");
 
@@ -188,7 +189,7 @@ public void assertOutputEqualsLiteral(final @NotNull String destination, final @
    * @throws IOException if failed to read one of the files
    * @since 1.1.0
    */
-  public void assertOutputEquals(final @NotNull String resourceName, final @NotNull String fileName) throws IOException {
+  public void assertOutputEquals(final String resourceName, final String fileName) throws IOException {
     final String actualOutput = this.readOutput(fileName);
 
     final StringBuilder builder = new StringBuilder();
@@ -215,7 +216,7 @@ public void assertOutputEquals(final @NotNull String resourceName, final @NotNul
    * @return the new runner
    * @since 1.1.0
    */
-  public @NotNull GradleRunner runner(final @NotNull String@NotNull... extraArgs) {
+  public GradleRunner runner(final String... extraArgs) {
     final List<String> args = new ArrayList<>(this.commonArguments.size() + extraArgs.length);
     args.addAll(this.commonArguments);
     Collections.addAll(args, extraArgs);
@@ -234,7 +235,7 @@ public void assertOutputEquals(final @NotNull String resourceName, final @NotNul
    * @return the result of an executed build
    * @since 1.1.0
    */
-  public @NotNull BuildResult build(final @NotNull String@NotNull... extraArgs) {
+  public BuildResult build(final String... extraArgs) {
     return this.runner(extraArgs).build();
   }
 

src/main/java/net/kyori/mammoth/Configurable.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of mammoth, licensed under the MIT License.
  *
- * Copyright (c) 2021-2022 KyoriPowered
+ * Copyright (c) 2021-2025 KyoriPowered
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -24,8 +24,8 @@
 package net.kyori.mammoth;
 
 import org.gradle.api.Action;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import static java.util.Objects.requireNonNull;
 
@@ -34,6 +34,7 @@
  *
  * @since 1.0.0
  */
+@NullMarked
 public final class Configurable {
   private Configurable() {
   }
@@ -47,7 +48,7 @@ private Configurable() {
    * @return the provided {@code instance}
    * @since 1.0.0
    */
-  public static <T> @NotNull T configure(final @NotNull T instance, final @NotNull Action<T> configureAction) {
+  public static <T> T configure(final T instance, final Action<T> configureAction) {
     requireNonNull(configureAction, "configureAction").execute(instance);
     return instance;
   }
@@ -61,7 +62,7 @@ private Configurable() {
    * @return the provided {@code instance}
    * @since 1.0.0
    */
-  public static <T> @NotNull T configureIfNonNull(final @NotNull T instance, final @Nullable Action<T> configureAction) {
+  public static <T> T configureIfNonNull(final T instance, final @Nullable Action<T> configureAction) {
     if (configureAction != null) {
       configureAction.execute(instance);
     }

src/main/java/net/kyori/mammoth/Extensions.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of mammoth, licensed under the MIT License.
  *
- * Copyright (c) 2021-2022 KyoriPowered
+ * Copyright (c) 2021-2025 KyoriPowered
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -24,12 +24,14 @@
 package net.kyori.mammoth;
 
 import org.gradle.api.plugins.ExtensionContainer;
+import org.jspecify.annotations.NullMarked;
 
 /**
  * Helpers for working with extensions.
  *
  * @since 1.0.0
  */
+@NullMarked
 public final class Extensions {
   private Extensions() {
   }

src/main/java/net/kyori/mammoth/GradleCompat.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of mammoth, licensed under the MIT License.
  *
- * Copyright (c) 2021-2023 KyoriPowered
+ * Copyright (c) 2021-2025 KyoriPowered
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -28,8 +28,10 @@
 import org.gradle.api.Project;
 import org.gradle.api.provider.Provider;
 import org.gradle.util.GradleVersion;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
+@NullMarked
 final class GradleCompat {
   static final boolean SHOULD_USE_CONVENTION = hasMethod(Project.class, "getConvention") && !hasMinGradleVersion("8.2");
   static final boolean HAS_FOR_USE_AT_CONFIGURATION_TIME = hasMethod(Provider.class, "forUseAtConfigurationTime") && !hasMinGradleVersion("7.6");

src/main/java/net/kyori/mammoth/IsolatingClassLoader.java

@@ -1,7 +1,7 @@
 /*
  * This file is part of mammoth, licensed under the MIT License.
  *
- * Copyright (c) 2024 KyoriPowered
+ * Copyright (c) 2024-2025 KyoriPowered
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -30,8 +30,8 @@
 import java.util.Iterator;
 import java.util.Set;
 import org.gradle.api.file.FileCollection;
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 /**
  * A factory for classloaders that will load classes from themselves rather than its parent where possible.
@@ -42,6 +42,7 @@
  *
  * @since 1.4.0
  */
+@NullMarked
 public final class IsolatingClassLoader {
   private IsolatingClassLoader() {
   }
@@ -54,7 +55,7 @@ private IsolatingClassLoader() {
    * @return the newly created loader
    * @since 1.4.0
    */
-  public static @NotNull URLClassLoader isolatingClassLoader(final @Nullable ClassLoader parent, final @NotNull URL @NotNull... urls) {
+  public static URLClassLoader isolatingClassLoader(final @Nullable ClassLoader parent, final URL... urls) {
     return new IsolatingClassLoaderImpl(urls, parent);
   }
 
@@ -66,7 +67,7 @@ private IsolatingClassLoader() {
    * @return the newly created loader
    * @since 1.4.0
    */
-  public static @NotNull URLClassLoader isolatingClassLoader(final @Nullable ClassLoader parent, final @NotNull FileCollection files) {
+  public static URLClassLoader isolatingClassLoader(final @Nullable ClassLoader parent, final FileCollection files) {
     final Set<File> unwrapped = files.getFiles();
     final URL[] urls = new URL[unwrapped.size()];
     final Iterator<File> it = files.iterator();