Use JSpecify for nullability constraints

Resolves #192

Signed-off-by: onobc <chris.bono@gmail.com>

Author: onobc

pom.xml

@@ -95,7 +95,7 @@
 		<spring-asciidoctor-backends.version>0.0.6</spring-asciidoctor-backends.version>
 
 		<!-- plugin versions -->
-		<maven-compiler-plugin.version>3.14.0</maven-compiler-plugin.version>
+		<maven-compiler-plugin.version>3.14.1</maven-compiler-plugin.version>
 		<maven-surefire-plugin.version>3.1.2</maven-surefire-plugin.version>
 		<maven-failsafe-plugin.version>3.1.2</maven-failsafe-plugin.version>
 		<maven-flatten-plugin.version>1.6.0</maven-flatten-plugin.version>
@@ -111,6 +111,9 @@
 		<maven-site-plugin.version>4.0.0-M13</maven-site-plugin.version>
 		<maven-project-info-reports-plugin.version>3.4.5</maven-project-info-reports-plugin.version>
 		<maven-jar-plugin.version>3.3.0</maven-jar-plugin.version>
+		<!-- Nullability plugins -->
+		<error-prone.version>2.44.0</error-prone.version>
+		<nullaway.version>0.12.12</nullaway.version>
 		<!-- BEGIN format + checkstyle properties -->
 		<spring-javaformat-maven-plugin.version>0.0.43</spring-javaformat-maven-plugin.version>
 		<maven-checkstyle-plugin.version>3.6.0</maven-checkstyle-plugin.version>
@@ -193,9 +196,39 @@
 				<version>${maven-compiler-plugin.version}</version>
 				<configuration>
 					<release>${java.version}</release>
+					<showWarnings>true</showWarnings>
 					<compilerArgs>
 						<compilerArg>-parameters</compilerArg>
+						<compilerArg>-Xdoclint:none</compilerArg>
+						<compilerArg>-Werror</compilerArg>
+						<compilerArg>-XDcompilePolicy=simple</compilerArg>
+						<compilerArg>--should-stop=ifError=FLOW</compilerArg>
+						<compilerArg>
+							-Xplugin:ErrorProne
+							<!-- Disable all built-in error prone checks -->
+							-XepDisableAllChecks
+							<!-- JSpecify mode https://github.com/uber/NullAway/wiki/JSpecify-Support -->
+							-XepOpt:NullAway:JSpecifyMode=true
+							<!-- Check JSpecify annotations -->
+							-Xep:NullAway:ERROR
+							-XepOpt:NullAway:OnlyNullMarked
+							-XepOpt:NullAway:TreatGeneratedAsUnannotated=true
+							<!-- https://github.com/uber/NullAway/issues/162 -->
+							-XepExcludedPaths:.*/src/test/java/.*
+						</compilerArg>
 					</compilerArgs>
+					<annotationProcessorPaths>
+						<path>
+							<groupId>com.google.errorprone</groupId>
+							<artifactId>error_prone_core</artifactId>
+							<version>${error-prone.version}</version>
+						</path>
+						<path>
+							<groupId>com.uber.nullaway</groupId>
+							<artifactId>nullaway</artifactId>
+							<version>${nullaway.version}</version>
+						</path>
+					</annotationProcessorPaths>
 				</configuration>
 			</plugin>
 			<plugin>

spring-grpc-build-dependencies/pom.xml

@@ -49,6 +49,7 @@
 	</licenses>
 
 	<properties>
+		<jspecify.version>1.0.0</jspecify.version>
 		<spring-framework.version>7.0.1</spring-framework.version>
 		<spring-security.version>7.0.0</spring-security.version>
 		<micrometer.version>1.16.0</micrometer.version>
@@ -94,6 +95,11 @@
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>
+			<dependency>
+				<groupId>org.jspecify</groupId>
+				<artifactId>jspecify</artifactId>
+				<version>${jspecify.version}</version>
+			</dependency>
 		</dependencies>
 	</dependencyManagement>
 

spring-grpc-core/pom.xml

@@ -23,6 +23,10 @@
 			<artifactId>spring-security-web</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.jspecify</groupId>
+			<artifactId>jspecify</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>io.grpc</groupId>
 			<artifactId>grpc-core</artifactId>

spring-grpc-core/src/main/java/org/springframework/grpc/client/DefaultGrpcChannelFactory.java

@@ -22,9 +22,10 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.core.log.LogAccessor;
-import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 import io.grpc.ChannelCredentials;

spring-grpc-core/src/main/java/org/springframework/grpc/client/aot/ClientBeanRegistrationsAotProcessor.java

@@ -23,6 +23,8 @@
 import java.util.HashSet;
 import java.util.Set;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.aot.generate.GenerationContext;
 import org.springframework.aot.hint.MemberCategory;
 import org.springframework.aot.hint.ReflectionHints;
@@ -36,7 +38,6 @@
 import org.springframework.beans.factory.support.RegisteredBean;
 import org.springframework.core.MethodParameter;
 import org.springframework.grpc.client.GrpcClientFactory;
-import org.springframework.lang.Nullable;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 

spring-grpc-core/src/main/java/org/springframework/grpc/package-info.java

@@ -14,4 +14,10 @@
  * limitations under the License.
  */
 
+/**
+ * Core module for Spring gRPC.
+ */
+@NullMarked
 package org.springframework.grpc;
+
+import org.jspecify.annotations.NullMarked;

spring-grpc-core/src/main/java/org/springframework/grpc/server/DefaultGrpcServerFactory.java

@@ -27,10 +27,10 @@
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.jspecify.annotations.Nullable;
 
 import org.springframework.grpc.internal.GrpcUtils;
 import org.springframework.grpc.server.service.ServerInterceptorFilter;
-import org.springframework.lang.Nullable;
 
 import io.grpc.Grpc;
 import io.grpc.InsecureServerCredentials;

spring-grpc-core/src/main/java/org/springframework/grpc/server/security/SslContextPreAuthenticationExtractor.java

@@ -23,7 +23,8 @@
 
 import javax.net.ssl.SSLSession;
 
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.security.core.Authentication;
 import org.springframework.security.web.authentication.preauth.PreAuthenticatedAuthenticationToken;
 import org.springframework.security.web.authentication.preauth.x509.SubjectDnX509PrincipalExtractor;

spring-grpc-core/src/main/java/org/springframework/grpc/server/service/DefaultGrpcServiceConfigurer.java

@@ -20,12 +20,13 @@
 import java.util.Arrays;
 import java.util.List;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.context.ApplicationContext;
 import org.springframework.grpc.internal.ApplicationContextBeanLookupUtils;
 import org.springframework.grpc.server.GlobalServerInterceptor;
 import org.springframework.grpc.server.GrpcServerFactory;
-import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 import io.grpc.BindableService;

spring-grpc-core/src/main/java/org/springframework/grpc/server/service/DefaultGrpcServiceDiscoverer.java

@@ -18,9 +18,10 @@
 
 import java.util.List;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.context.ApplicationContext;
 import org.springframework.grpc.internal.ApplicationContextBeanLookupUtils;
-import org.springframework.lang.Nullable;
 
 import io.grpc.BindableService;
 import io.grpc.ServerServiceDefinition;