8256809: Annotation processing causes NPE during flow analysis

Reviewed-by: jlahoda

src/jdk.compiler/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java

@@ -1341,8 +1341,9 @@ private void newRound() {
             if (foundError) {
                 for (ClassSymbol cs : symtab.getAllClasses()) {
                     if (cs.classfile != null || cs.kind == ERR) {
+                        Kinds.Kind symKind = cs.kind;
                         cs.reset();
-                        if (cs.kind == ERR) {
+                        if (symKind == ERR) {
                             cs.type = new ClassType(cs.type.getEnclosingType(), null, cs);
                         }
                         if (cs.isCompleted()) {

test/langtools/tools/javac/processing/rounds/ErrClassSymbolTypeFixed.java

@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, Red Hat, Inc.
+ * 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 8256809
+ * @summary Verify that erroneous symbols have their type fixed between rounds
+ * @library /tools/lib /tools/javac/lib
+ * @modules
+ *      jdk.compiler/com.sun.tools.javac.api
+ *      jdk.compiler/com.sun.tools.javac.main
+ * @build toolbox.ToolBox toolbox.JavacTask toolbox.JarTask toolbox.TestRunner
+ *      JavacTestingAbstractProcessor
+ * @run main ErrClassSymbolTypeFixed
+ */
+
+import java.io.IOException;
+import java.io.Writer;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Set;
+
+import javax.annotation.processing.RoundEnvironment;
+import javax.annotation.processing.SupportedAnnotationTypes;
+import javax.lang.model.element.TypeElement;
+import javax.lang.model.util.ElementFilter;
+import javax.tools.Diagnostic;
+import javax.tools.JavaFileObject;
+
+import toolbox.JavacTask;
+import toolbox.JarTask;
+import toolbox.Task;
+import toolbox.TestRunner;
+import toolbox.ToolBox;
+
+public class ErrClassSymbolTypeFixed extends TestRunner {
+
+    private static final String A_JAVA = "package t1; public @interface A {}";
+    private static final String B_JAVA = "package t2; public class B {}";
+    private static final String C_JAVA = "package t3; import t2.B; public class C extends B {}";
+    private static final String D_JAVA = "import t1.A; import t3.C; import t2.B; @A public class D {}";
+
+    private ToolBox tb;
+
+    public ErrClassSymbolTypeFixed() {
+        super(System.err);
+        tb = new ToolBox();
+    }
+
+    public static void main(String... args) throws Exception {
+        new ErrClassSymbolTypeFixed().runTests();
+    }
+
+    @Test
+    public void testErrorFixed() throws Exception {
+        Path base = Paths.get(".");
+        Path src1 = base.resolve("src1");
+        Path src2 = base.resolve("src2");
+        Path classes = base.resolve("classes");
+
+        Files.createDirectories(classes);
+
+        /*
+         *  Create and compile the following:
+         *  A: annotation type
+         *  B: basic class
+         *  C: subclass of B
+         */
+        tb.writeJavaFiles(src1, A_JAVA, B_JAVA, C_JAVA);
+
+        new JavacTask(tb)
+        .outdir(classes)
+        .files(tb.findJavaFiles(src1))
+        .run()
+        .writeAll()
+        .getOutput(Task.OutputKind.DIRECT);
+
+        // Create a Jar containing only C to include later in the classpath
+        Path jarPath = base.resolve("test.jar");
+        new JarTask(tb, jarPath)
+        .baseDir(classes)
+        .files("t3")
+        .run()
+        .writeAll()
+        .getOutput(Task.OutputKind.DIRECT);
+
+        // Delete B from the classpath
+        Files.delete(classes.resolve("t2").resolve("B.class"));
+
+        /*
+         *  Write and compile D, which has the following properties:
+         *  - is annotated with A, causing our processor to regenerate B
+         *  - imports C before B
+         */
+        tb.writeJavaFiles(src2, D_JAVA);
+
+        // If the erroneous ClassSymbol is not reset between rounds,
+        // a NullPointerException will occur later during flow analysis.
+        new JavacTask(tb)
+        .classpath(classes, jarPath)
+        .options("-processor", ErrClassSymbolProcessor.class.getName(),
+                "--processor-path", System.getProperty("test.class.path"))
+        .outdir(classes)
+        .files(tb.findJavaFiles(src2))
+        .run()
+        .writeAll()
+        .getOutput(Task.OutputKind.DIRECT);
+    }
+
+    @SupportedAnnotationTypes("t1.A")
+    public static class ErrClassSymbolProcessor extends JavacTestingAbstractProcessor {
+
+        @Override
+        public final boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+            for (TypeElement te : ElementFilter.typesIn(roundEnv.getRootElements())) {
+                createFile(te);
+            }
+            return true;
+        }
+
+        private void createFile(TypeElement te) {
+            // Generate B.java when the processor reads the @A annotation on D
+            if ("D".equals(te.getSimpleName().toString())) {
+                try {
+                    JavaFileObject fo = processingEnv.getFiler().createSourceFile("B");
+                    try (Writer out = fo.openWriter()) {
+                        out.write(B_JAVA);
+                    }
+                } catch (IOException e) {
+                    messager.printMessage(Diagnostic.Kind.ERROR, "problem writing file: " + e);
+                }
+            }
+        }
+    }
+
+}