GH-1192 - Migrate code base to jSpecify for nullness verification.

Author: odrotbohm

.github/workflows/build.yaml

@@ -31,4 +31,4 @@ jobs:
         ARTIFACTORY_USERNAME: ${{ secrets.ARTIFACTORY_USERNAME }}
         ARTIFACTORY_PASSWORD: ${{ secrets.ARTIFACTORY_PASSWORD }}
         DEVELOCITY_ACCESS_KEY: ${{ secrets.GRADLE_ENTERPRISE_SECRET_ACCESS_KEY }}
-      run: ./mvnw -B clean deploy -Pci,artifactory
+      run: ./mvnw -B clean deploy -Pci,artifactory,nullaway

.mvn/jvm.config

@@ -0,0 +1,10 @@
+--add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
+--add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
+--add-opens jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
+--add-opens jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED

pom.xml

@@ -37,10 +37,12 @@
 
 		<archunit.version>1.4.0</archunit.version>
 		<artifactory-maven-plugin.version>3.6.2</artifactory-maven-plugin.version>
+		<errorprone.version>2.36.0</errorprone.version>
 		<flapdoodle-mongodb.version>4.16.1</flapdoodle-mongodb.version>
 		<jgit.version>7.0.0.202409031743-r</jgit.version>
 		<jgrapht.version>1.5.2</jgrapht.version>
 		<jmolecules-bom.version>2023.3.1</jmolecules-bom.version>
+		<nullaway.version>0.12.7</nullaway.version>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 		<spring-boot.version>4.0.0-SNAPSHOT</spring-boot.version>
@@ -431,6 +433,54 @@ limitations under the License.
 			</build>
 		</profile>
 
+		<profile>
+			<id>nullaway</id>
+			<build>
+				<plugins>
+					<plugin>
+						<groupId>org.apache.maven.plugins</groupId>
+						<artifactId>maven-compiler-plugin</artifactId>
+						<configuration>
+							<showWarnings>true</showWarnings>
+							
+						</configuration>
+						<executions>
+							<execution>
+								<id>default-compile</id>
+								<phase>none</phase>
+							</execution>
+							<execution>
+								<id>java-compile</id>
+								<phase>compile</phase>
+								<goals>
+									<goal>compile</goal>
+								</goals>
+								<configuration>
+									<annotationProcessorPaths>
+										<path>
+											<groupId>com.google.errorprone</groupId>
+											<artifactId>error_prone_core</artifactId>
+											<version>${errorprone.version}</version>
+										</path>
+										<path>
+											<groupId>com.uber.nullaway</groupId>
+											<artifactId>nullaway</artifactId>
+											<version>${nullaway.version}</version>
+										</path>
+									</annotationProcessorPaths>
+									<compilerArgs>
+										<arg>-XDcompilePolicy=simple</arg>
+										<arg>--should-stop=ifError=FLOW</arg>
+										<arg>-Xplugin:ErrorProne -XepDisableAllChecks -Xep:NullAway:ERROR -XepOpt:NullAway:OnlyNullMarked=true -XepOpt:NullAway:CustomContractAnnotations=org.springframework.lang.Contract</arg>
+									</compilerArgs>
+								</configuration>
+							</execution>
+						</executions>
+					</plugin>
+				</plugins>
+			</build>
+		</profile>
+
 	</profiles>
 
 	<dependencies>

spring-modulith-actuator/pom.xml

@@ -16,6 +16,11 @@
 
 	<dependencies>
 
+    <dependency>
+      <groupId>org.jspecify</groupId>
+      <artifactId>jspecify</artifactId>
+    </dependency>
+
 		<dependency>
 			<groupId>org.springframework.modulith</groupId>
 			<artifactId>spring-modulith-runtime</artifactId>

spring-modulith-actuator/src/main/java/org/springframework/modulith/actuator/autoconfigure/package-info.java

@@ -1,5 +1,5 @@
 /**
  * Autoconfiguration for Spring Modulith actuators.
  */
-@org.springframework.lang.NonNullApi
+@org.jspecify.annotations.NullMarked
 package org.springframework.modulith.actuator.autoconfigure;

spring-modulith-actuator/src/main/java/org/springframework/modulith/actuator/package-info.java

@@ -1,5 +1,5 @@
 /**
  * Spring Boot actuator support for Spring Modulith.
  */
-@org.springframework.lang.NonNullApi
+@org.jspecify.annotations.NullMarked
 package org.springframework.modulith.actuator;

spring-modulith-api/pom.xml

@@ -17,6 +17,11 @@
 
 	<dependencies>
 
+		<dependency>
+			<groupId>org.jspecify</groupId>
+			<artifactId>jspecify</artifactId>
+		</dependency>
+
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-autoconfigure</artifactId>

spring-modulith-api/src/main/java/org/springframework/modulith/package-info.java

@@ -1,5 +1,5 @@
 /**
  * Core abstractions of Spring Modulith. To be referred to in user applications.
  */
-@org.springframework.lang.NonNullApi
+@org.jspecify.annotations.NullMarked
 package org.springframework.modulith;

spring-modulith-apt/pom.xml

@@ -21,6 +21,10 @@
 			<artifactId>aptk-tools</artifactId>
 			<version>0.29.0</version>
 		</dependency>
+    <dependency>
+      <groupId>org.jspecify</groupId>
+      <artifactId>jspecify</artifactId>
+    </dependency>
 
 		<dependency>
 			<groupId>org.springframework.boot</groupId>

spring-modulith-apt/src/main/java/org/springframework/modulith/apt/SpringModulithProcessor.java

@@ -19,6 +19,7 @@
 import io.toolisticon.aptk.tools.wrapper.ElementWrapper;
 import io.toolisticon.aptk.tools.wrapper.ExecutableElementWrapper;
 import io.toolisticon.aptk.tools.wrapper.TypeElementWrapper;
+import org.jspecify.annotations.Nullable;
 
 import java.io.File;
 import java.io.FileWriter;
@@ -50,7 +51,6 @@
 import javax.tools.StandardLocation;
 
 import org.springframework.boot.json.JsonWriter;
-import org.springframework.lang.Nullable;
 import org.springframework.modulith.docs.metadata.MethodMetadata;
 import org.springframework.modulith.docs.metadata.TypeMetadata;
 import org.springframework.modulith.docs.util.BuildSystemUtils;