Fix Symbol$CompletionFailure crash when building CFG (typetools#6397)

Co-authored-by: Michael Ernst <mernst@cs.washington.edu>

checker/build.gradle

@@ -90,6 +90,9 @@ dependencies {
   testImplementation 'org.apiguardian:apiguardian-api:1.1.2'
   // For tests that use JSpecify annotations
   testImplementation 'org.jspecify:jspecify:1.0.0'
+  // To test for an obscure crash in CFG construction for try-with-resources;
+  // see https://github.com/typetools/checker-framework/issues/6396
+  testImplementation 'org.apache.spark:spark-sql_2.12:3.3.2'
 
   // Required for checker/tests/index-initializedfields/RequireJavadoc.java
   if (JavaVersion.current() == JavaVersion.VERSION_1_8) {
@@ -1201,3 +1204,4 @@ publishing {
 signing {
   sign publishing.publications.checker
 }
+

checker/tests/resourceleak/SparkSessionCFGCrash.java

@@ -0,0 +1,10 @@
+// To test crash in CFG construction for try-with-resources
+// See https://github.com/typetools/checker-framework/issues/6396
+import org.apache.spark.sql.SparkSession;
+
+public class SparkSessionCFGCrash {
+
+  private void run() {
+    try (SparkSession session = SparkSession.builder().getOrCreate()) {}
+  }
+}

javacutil/src/main/java/org/checkerframework/javacutil/trees/TreeBuilder.java

@@ -22,6 +22,7 @@
 import com.sun.tools.javac.tree.TreeInfo;
 import com.sun.tools.javac.tree.TreeMaker;
 import com.sun.tools.javac.util.Context;
+import com.sun.tools.javac.util.Name;
 import com.sun.tools.javac.util.Names;
 import java.util.List;
 import javax.annotation.processing.ProcessingEnvironment;
@@ -46,14 +47,40 @@
  * TreeMaker.
  */
 public class TreeBuilder {
+
+  /** The javac {@link Elements} object. */
   protected final Elements elements;
+
+  /** The javac {@link javax.lang.model.util.Types} object. */
   protected final Types modelTypes;
+
+  /** The internal javac {@link com.sun.tools.javac.code.Types} object. */
   protected final com.sun.tools.javac.code.Types javacTypes;
+
+  /** For constructing trees */
   protected final TreeMaker maker;
+
+  /** The javac {@link Names} object. */
   protected final Names names;
+
+  /** The javac {@link Symtab} object. */
   protected final Symtab symtab;
+
+  /** The javac {@link ProcessingEnvironment} */
   protected final ProcessingEnvironment env;
 
+  /**
+   * {@link Name} object for "close", used when building a tree for a call to {@code close()}.
+   *
+   * @see #buildCloseMethodAccess(ExpressionTree)
+   */
+  private final Name closeName;
+
+  /**
+   * Creates a new TreeBuilder.
+   *
+   * @param env the javac {@link ProcessingEnvironment}
+   */
   public TreeBuilder(ProcessingEnvironment env) {
     this.env = env;
     Context context = ((JavacProcessingEnvironment) env).getContext();
@@ -63,6 +90,7 @@ public TreeBuilder(ProcessingEnvironment env) {
     maker = TreeMaker.instance(context);
     names = Names.instance(context);
     symtab = Symtab.instance(context);
+    closeName = names.fromString("close");
   }
 
   /**
@@ -145,10 +173,20 @@ public MemberSelectTree buildCloseMethodAccess(ExpressionTree autoCloseableExpr)
     // Find the close() method
     Symbol.MethodSymbol closeMethod = null;
 
-    for (ExecutableElement method : ElementFilter.methodsIn(elements.getAllMembers(exprElement))) {
-      if (method.getParameters().isEmpty() && method.getSimpleName().contentEquals("close")) {
-        closeMethod = (Symbol.MethodSymbol) method;
-        break;
+    // We could use elements.getAllMembers(exprElement) to find the close method, but in rare cases
+    // calling that method crashes with a Symbol$CompletionFailure exception.  See
+    // https://github.com/typetools/checker-framework/issues/6396.  The code below directly searches
+    // all supertypes for the method and avoids the crash.
+    for (Type s : javacTypes.closure(((Symbol) exprElement).type)) {
+      for (Symbol m : s.tsym.members().getSymbolsByName(closeName)) {
+        if (!(m instanceof Symbol.MethodSymbol)) {
+          continue;
+        }
+        Symbol.MethodSymbol msym = (Symbol.MethodSymbol) m;
+        if (!msym.isStatic() && msym.getParameters().isEmpty()) {
+          closeMethod = msym;
+          break;
+        }
       }
     }