8355065: ConcurrentModificationException in RichDiagnosticFormatter

src/jdk.compiler/share/classes/com/sun/tools/javac/util/RichDiagnosticFormatter.java

@@ -83,8 +83,37 @@ public class RichDiagnosticFormatter extends
     /* type/symbol printer used by this formatter */
     private RichPrinter printer;
 
+    private static class WhereClauses {
+        private final Map<WhereClauseKind, Map<Type, JCDiagnostic>> whereClauses;
+
+        WhereClauses() {
+            Map<WhereClauseKind, Map<Type, JCDiagnostic>> whereClauses = new EnumMap<>(WhereClauseKind.class);
+            for (WhereClauseKind kind : WhereClauseKind.values()) {
+                whereClauses.put(kind, new LinkedHashMap<>());
+            }
+            this.whereClauses = whereClauses;
+        }
+
+        public Map<Type, JCDiagnostic> get(WhereClauseKind kind) {
+            return whereClauses.get(kind);
+        }
+    }
+
     /* map for keeping track of a where clause associated to a given type */
-    Map<WhereClauseKind, Map<Type, JCDiagnostic>> whereClauses;
+    WhereClauses whereClauses;
+
+    private void enter() {
+        if (nameSimplifier != null || whereClauses != null) {
+            throw new IllegalStateException();
+        }
+        nameSimplifier = new ClassNameSimplifier();
+        whereClauses = new WhereClauses();
+    }
+
+    private void exit() {
+        nameSimplifier = null;
+        whereClauses = null;
+    }
 
     /** Get the DiagnosticFormatter instance for this context. */
     public static RichDiagnosticFormatter instance(Context context) {
@@ -102,39 +131,42 @@ protected RichDiagnosticFormatter(Context context) {
         this.diags = JCDiagnostic.Factory.instance(context);
         this.types = Types.instance(context);
         this.messages = JavacMessages.instance(context);
-        whereClauses = new EnumMap<>(WhereClauseKind.class);
         configuration = new RichConfiguration(Options.instance(context), formatter);
-        for (WhereClauseKind kind : WhereClauseKind.values())
-            whereClauses.put(kind, new LinkedHashMap<Type, JCDiagnostic>());
     }
 
     @Override
     public String format(JCDiagnostic diag, Locale l) {
-        StringBuilder sb = new StringBuilder();
-        nameSimplifier = new ClassNameSimplifier();
-        for (WhereClauseKind kind : WhereClauseKind.values())
-            whereClauses.get(kind).clear();
-        preprocessDiagnostic(diag);
-        sb.append(formatter.format(diag, l));
-        if (getConfiguration().isEnabled(RichFormatterFeature.WHERE_CLAUSES)) {
-            List<JCDiagnostic> clauses = getWhereClauses();
-            String indent = formatter.isRaw() ? "" :
-                formatter.indentString(DetailsInc);
-            for (JCDiagnostic d : clauses) {
-                String whereClause = formatter.format(d, l);
-                if (whereClause.length() > 0) {
-                    sb.append('\n' + indent + whereClause);
+        enter();
+        try {
+            StringBuilder sb = new StringBuilder();
+            preprocessDiagnostic(diag);
+            sb.append(formatter.format(diag, l));
+            if (getConfiguration().isEnabled(RichFormatterFeature.WHERE_CLAUSES)) {
+                List<JCDiagnostic> clauses = getWhereClauses();
+                String indent = formatter.isRaw() ? "" :
+                        formatter.indentString(DetailsInc);
+                for (JCDiagnostic d : clauses) {
+                    String whereClause = formatter.format(d, l);
+                    if (whereClause.length() > 0) {
+                        sb.append('\n' + indent + whereClause);
+                    }
                 }
             }
+            return sb.toString();
+        } finally {
+            exit();
         }
-        return sb.toString();
     }
 
     @Override
     public String formatMessage(JCDiagnostic diag, Locale l) {
-        nameSimplifier = new ClassNameSimplifier();
-        preprocessDiagnostic(diag);
-        return super.formatMessage(diag, l);
+        enter();
+        try {
+            preprocessDiagnostic(diag);
+            return super.formatMessage(diag, l);
+        } finally {
+            exit();
+        }
     }
 
     /**
@@ -556,7 +588,7 @@ public Void visitClassType(ClassType t, Void ignored) {
 
         @Override
         public Void visitTypeVar(TypeVar t, Void ignored) {
-            t = (TypeVar)t.stripMetadataIfNeeded();
+            t = (TypeVar)t.stripMetadata();
             if (indexOf(t, WhereClauseKind.TYPEVAR) == -1) {
                 //access the bound type and skip error types
                 Type bound = t.getUpperBound();

test/langtools/tools/javac/annotations/typeAnnotations/RichFormatterWithTypeAnnotationsTest.java

@@ -0,0 +1,133 @@
+/*
+ * Copyright (c) 2025, Google LLC. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8355065
+ * @summary ConcurrentModificationException in RichDiagnosticFormatter
+ * @library /tools/lib
+ * @modules jdk.compiler/com.sun.tools.javac.main jdk.compiler/com.sun.tools.javac.api
+ * @build toolbox.ToolBox toolbox.JavacTask
+ * @run main RichFormatterWithTypeAnnotationsTest
+ */
+import toolbox.JavacTask;
+import toolbox.Task;
+import toolbox.TestRunner;
+import toolbox.ToolBox;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Arrays;
+import java.util.List;
+
+public class RichFormatterWithTypeAnnotationsTest extends TestRunner {
+    ToolBox tb;
+
+    public RichFormatterWithTypeAnnotationsTest() {
+        super(System.err);
+        tb = new ToolBox();
+    }
+
+    public static void main(String[] args) throws Exception {
+        new RichFormatterWithTypeAnnotationsTest()
+                .runTests(m -> new Object[] {Paths.get(m.getName())});
+    }
+
+    @Test
+    public void test(Path base) throws Exception {
+        Path libClasses = base.resolve("libclasses");
+        Files.createDirectories(libClasses);
+        new JavacTask(tb)
+                .outdir(libClasses)
+                .sources(
+                        """
+                        package lib;
+                        enum Bar {
+                          BAZ
+                        }
+                        """,
+                        """
+                        package lib;
+                        import java.lang.annotation.ElementType;
+                        import java.lang.annotation.Retention;
+                        import java.lang.annotation.RetentionPolicy;
+                        import java.lang.annotation.Target;
+
+                        @Retention(RetentionPolicy.RUNTIME)
+                        @interface Foo {
+                          Bar value();
+                        }
+                        """,
+                        """
+                        package lib;
+                        import java.lang.annotation.ElementType;
+                        import java.lang.annotation.Retention;
+                        import java.lang.annotation.RetentionPolicy;
+                        import java.lang.annotation.Target;
+
+                        @Retention(RetentionPolicy.RUNTIME)
+                        @Target({ElementType.TYPE_USE, ElementType.TYPE_PARAMETER})
+                        @Foo(Bar.BAZ)
+                        @interface A {}
+                        """,
+                        """
+                        package lib;
+                        public interface M<K, V> {
+                          @A
+                          V f(K k, V v);
+                        }
+                        """)
+                .options()
+                .run()
+                .writeAll();
+        Files.delete(libClasses.resolve("lib").resolve("Bar.class"));
+        String code =
+                """
+                import lib.M;
+                class T {
+                  protected M m;
+
+                  public void f() {
+                    m.f(null, 0);
+                  }
+                }
+                """;
+        List<String> output =
+                new JavacTask(tb)
+                        .classpath(libClasses)
+                        .sources(code)
+                        .options("-Xlint:all", "-Werror", "-XDrawDiagnostics")
+                        .run(Task.Expect.FAIL)
+                        .writeAll()
+                        .getOutputLines(Task.OutputKind.DIRECT);
+        List<String> expected =
+                Arrays.asList(
+                        "T.java:3:13: compiler.warn.raw.class.use: lib.M, lib.M<K,V>",
+                        "T.java:6:8: compiler.warn.unchecked.call.mbr.of.raw.type: f(K,V), lib.M",
+                        "- compiler.err.warnings.and.werror",
+                        "1 error",
+                        "2 warnings");
+        tb.checkEqual(expected, output);
+    }
+}