Prepare for JDK 21

Added test for null case (covering uber#831) and changed JDK 17 to JDK 21 for unit testing

code-coverage-report/build.gradle

@@ -20,12 +20,12 @@ plugins {
     id 'jacoco'
 }
 
-// Use JDK 17 for this module, via a toolchain.  We need JDK 17 since this module
-// depends on jdk17-unit-tests.
+// Use JDK 21 for this module, via a toolchain.  We need JDK 21 since this module
+// depends on jdk-recent-unit-tests.
 // We must null out sourceCompatibility and targetCompatibility to use toolchains.
 java.sourceCompatibility = null
 java.targetCompatibility = null
-java.toolchain.languageVersion.set JavaLanguageVersion.of(17)
+java.toolchain.languageVersion.set JavaLanguageVersion.of(21)
 
 // A resolvable configuration to collect source code
 def sourcesPath = configurations.create("sourcesPath") {

jdk17-unit-tests/build.gradle → jdk-recent-unit-tests/build.gradle

@@ -18,11 +18,11 @@ plugins {
     id 'nullaway.java-test-conventions'
 }
 
-// Use JDK 17 for this module, via a toolchain
+// Use JDK 21 for this module, via a toolchain
 // We must null out sourceCompatibility and targetCompatibility to use toolchains.
 java.sourceCompatibility = null
 java.targetCompatibility = null
-java.toolchain.languageVersion.set JavaLanguageVersion.of(17)
+java.toolchain.languageVersion.set JavaLanguageVersion.of(21)
 
 configurations {
     // We use this configuration to expose a module path that can be

jdk17-unit-tests/src/test/java/com/uber/nullaway/jdk17/NullAwaySwitchTests.java → jdk-recent-unit-tests/src/test/java/com/uber/nullaway/jdk17/NullAwaySwitchTests.java

@@ -25,6 +25,7 @@
 import com.uber.nullaway.NullAway;
 import java.util.Arrays;
 import org.junit.Before;
+import org.junit.Ignore;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
@@ -174,4 +175,30 @@ public void testSwitchExprLambda() {
             "}")
         .doTest();
   }
+
+  @Ignore
+  @Test
+  public void testSwitchExprNullCase() {
+    defaultCompilationHelper
+        .addSourceLines(
+            "SwitchExpr.java",
+            "package com.uber;",
+            "import javax.annotation.Nullable;",
+            "class SwitchExpr {",
+            "  public enum NullableEnum {",
+            "    a,",
+            "    b,",
+            "  }",
+            "  // NOTE: we should report a bug here for nullableEn but cannot do so until",
+            "  // Error Prone supports matching switch expressions",
+            "  static Object handleNullableEnum(@Nullable NullableEnum nullableEnum) {",
+            "    return switch (nullableEnum) {",
+            "      case a -> new Object();",
+            "      case b -> new Object();",
+            "      case null -> throw new IllegalArgumentException(\"NullableEnum parameter is required\");",
+            "    };",
+            "  }",
+            "}")
+        .doTest();
+  }
 }

settings.gradle

@@ -23,7 +23,7 @@ include ':jar-infer:test-java-lib-jarinfer'
 include ':jar-infer:nullaway-integration-test'
 include ':jmh'
 include ':guava-recent-unit-tests'
-include ':jdk17-unit-tests'
+include ':jdk-recent-unit-tests'
 include ':code-coverage-report'
 include ':sample-app'
 include ':jar-infer:test-android-lib-jarinfer'