Fix MustBeClosedChecker crash on flexible constructors.

graememorgan · Error Prone Team · commit 7926dbce13ea · 2026-02-25T08:43:20.000-08:00
Fixes external #5529 PiperOrigin-RevId: 875182882
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/MustBeClosedChecker.java b/core/src/main/java/com/google/errorprone/bugpatterns/MustBeClosedChecker.java
@@ -38,12 +38,12 @@
 import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.tree.ClassTree;
 import com.sun.source.tree.ExpressionStatementTree;
+import com.sun.source.tree.IdentifierTree;
 import com.sun.source.tree.MethodInvocationTree;
 import com.sun.source.tree.MethodTree;
 import com.sun.source.tree.StatementTree;
 import com.sun.source.tree.Tree;
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
-import java.util.List;
 
 /**
  * Checks if a constructor or method annotated with {@link
@@ -159,15 +159,19 @@ public Description matchClass(ClassTree tree, VisitorState state) {
   }
 
   private static boolean invokedConstructorMustBeClosed(VisitorState state, MethodTree methodTree) {
-    // The first statement in a constructor should be an invocation of the super/this constructor.
-    List<? extends StatementTree> statements = methodTree.getBody().getStatements();
-    if (statements.isEmpty()) {
-      // Not sure how the body would be empty, but just filter it out in case.
-      return false;
+    for (StatementTree statement : methodTree.getBody().getStatements()) {
+      if (!(statement instanceof ExpressionStatementTree est)) {
+        continue;
+      }
+      if (!(est.getExpression() instanceof MethodInvocationTree mit)) {
+        continue;
+      }
+      if (mit.getMethodSelect() instanceof IdentifierTree id
+          && (id.getName().contentEquals("super") || id.getName().contentEquals("this"))) {
+        MethodSymbol invokedConstructorSymbol = ASTHelpers.getSymbol(mit);
+        return hasAnnotation(invokedConstructorSymbol, MUST_BE_CLOSED_ANNOTATION, state);
+      }
     }
-    ExpressionStatementTree est = (ExpressionStatementTree) statements.getFirst();
-    MethodInvocationTree mit = (MethodInvocationTree) est.getExpression();
-    MethodSymbol invokedConstructorSymbol = ASTHelpers.getSymbol(mit);
-    return hasAnnotation(invokedConstructorSymbol, MUST_BE_CLOSED_ANNOTATION, state);
+    return false;
   }
 }
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/MustBeClosedCheckerTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/MustBeClosedCheckerTest.java
@@ -16,6 +16,8 @@
 
 package com.google.errorprone.bugpatterns;
 
+import static com.google.common.truth.TruthJUnit.assume;
+
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.Ignore;
@@ -940,6 +942,52 @@ void forLoopUpdate() {
         .doTest();
   }
 
+  @Test
+  public void flexibleConstructor() {
+    assume().that(Runtime.version().feature()).isAtLeast(22);
+
+    compilationHelper
+        .addSourceLines(
+            "Test.java",
+            """
+            import com.google.errorprone.annotations.MustBeClosed;
+
+            class Test {
+              static class Parent implements AutoCloseable {
+                @MustBeClosed
+                Parent() {}
+
+                @Override
+                public void close() {}
+              }
+
+              static class Child extends Parent {
+                // BUG: Diagnostic contains: Invoked constructor is marked @MustBeClosed
+                Child(int i) {
+                  i++;
+                  super();
+                }
+              }
+
+              static class Other implements AutoCloseable {
+                @MustBeClosed
+                Other(int i) {}
+
+                // BUG: Diagnostic contains: Invoked constructor is marked @MustBeClosed
+                Other() {
+                  int i = 1;
+                  this(i);
+                }
+
+                @Override
+                public void close() {}
+              }
+            }
+            """)
+        .setArgs("--enable-preview", "--release", Integer.toString(Runtime.version().feature()))
+        .doTest();
+  }
+
   @Test
   public void localVariableTypeInference() {
     refactoringHelper
