SONARJAVA-5059 Fix S6901 ClassCastException when methods are called o…

…n `this` (#4865)
SonarSource · Sep 16, 2024 · f40dbdc · f40dbdc
1 parent 8db836f
commit f40dbdc
Show file tree

Hide file tree

Showing 2 changed files with 37 additions and 9 deletions.
diff --git a/...ecks-test-sources/default/src/main/java/checks/VirtualThreadUnsupportedMethodsSample.java b/...ecks-test-sources/default/src/main/java/checks/VirtualThreadUnsupportedMethodsSample.java
@@ -93,4 +93,21 @@ void falseNegatives(Thread virtualAtRuntime){
     outerVirtualThread.setDaemon(true); // False negative
   }
 
+  class IdentifierTreeImplTest {
+
+    SampleThread thread = new SampleThread();
+
+    public void test() {
+      thread.start();
+    }
+
+    private class SampleThread extends Thread {
+      @Override
+      public void run() {
+        setDaemon(true); // generates => mit.methodSelect() instanceof IdentifierTreeImpl
+      }
+    }
+
+  }
+
 }
diff --git a/java-checks/src/main/java/org/sonar/java/checks/VirtualThreadUnsupportedMethodsCheck.java b/java-checks/src/main/java/org/sonar/java/checks/VirtualThreadUnsupportedMethodsCheck.java
@@ -21,6 +21,8 @@
 
 import java.util.List;
 import java.util.Optional;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.sonar.check.Rule;
 import org.sonar.java.checks.methods.AbstractMethodDetection;
 import org.sonar.java.model.ExpressionUtils;
@@ -37,6 +39,8 @@
 @Rule(key = "S6901")
 public class VirtualThreadUnsupportedMethodsCheck extends AbstractMethodDetection implements JavaVersionAwareVisitor {
 
+  private static final Logger LOG = LoggerFactory.getLogger(VirtualThreadUnsupportedMethodsCheck.class);
+
   private static final String ISSUE_MESSAGE = "Method '%s' is not supported on virtual threads.";
   private static final String SECONDARY_LOCATION_ISSUE_MESSAGE = "Virtual thread initialized here.";
 
@@ -69,15 +73,22 @@ protected MethodMatchers getMethodInvocationMatchers() {
 
   @Override
   protected void onMethodInvocationFound(MethodInvocationTree mit) {
-    var memberSelect = (MemberSelectExpressionTree) mit.methodSelect();
-    var expression = memberSelect.expression();
-    var virtualThreadExpression = getVirtualThreadInitializer(expression);
-    if (virtualThreadExpression.isPresent()) {
-      reportIssue(
-        memberSelect.identifier(),
-        String.format(ISSUE_MESSAGE, memberSelect.identifier().name()),
-        List.of(new JavaFileScannerContext.Location(SECONDARY_LOCATION_ISSUE_MESSAGE, ExpressionUtils.methodName(virtualThreadExpression.get()))),
-        null);
+    // instance can be IdentifierTreeImpl, for example, so guard against class cast exception
+    if (mit.methodSelect() instanceof MemberSelectExpressionTree memberSelect) {
+      var expression = memberSelect.expression();
+      var virtualThreadExpression = getVirtualThreadInitializer(expression);
+      if (virtualThreadExpression.isPresent()) {
+        reportIssue(
+          memberSelect.identifier(),
+          String.format(ISSUE_MESSAGE, memberSelect.identifier().name()),
+          List.of(new JavaFileScannerContext.Location(SECONDARY_LOCATION_ISSUE_MESSAGE,
+            ExpressionUtils.methodName(virtualThreadExpression.get()))),
+          null);
+      }
+    } else {
+      LOG.trace("VirtualThreadUnsupportedMethodsCheck.onMethodInvocationFound(): " +
+          "mit.methodSelect() returns unsupported class instance: {}",
+        mit.methodSelect().getClass());
     }
   }