8029145: javadoc fails with java.lang.IllegalStateException: endPosTable already set

Reviewed-by: jjg

src/share/classes/com/sun/tools/javadoc/JavadocTool.java

 /*
- * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2014, Oracle and/or its affiliates. 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
@@ -30,6 +30,7 @@ import java.io.IOException;
 import java.util.Collection;
 import java.util.EnumSet;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 import javax.tools.JavaFileManager.Location;
@@ -238,11 +239,14 @@ public class JavadocTool extends com.sun.tools.javac.main.JavaCompiler {
             files = lb.toList();
         }
 
+        Set<JavaFileObject> ufiles = new HashSet<>();
         for (JavaFileObject fo : files) {
+            if (ufiles.add(fo)) { // ignore duplicates
                 // messager.notice("main.Loading_source_file", fn);
                 trees.append(parse(fo));
                 hasFiles = true;
             }
+        }
 
         if (!hasFiles) {
             messager.warning(Messager.NOPOS, "main.no_source_files_for_package",

test/tools/javadoc/parser/7091528/T7091528.java

 /*
- * Copyright (c) 2009, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2014, Oracle and/or its affiliates. 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
@@ -23,8 +23,8 @@
 
 /**
  * @test
- * @bug     7091528
- * @summary javadoc attempts to parse .class files
+ * @bug     7091528 8029145
+ * @summary ensures javadoc parses unique source files and ignores all class files
  * @compile p/C1.java p/q/C2.java
  * @run main T7091528
  */
@@ -37,17 +37,22 @@ public class T7091528 {
     public static void main(String... args) {
         new T7091528().run();
     }
-
     void run() {
         File testSrc = new File(System.getProperty("test.src"));
         File testClasses = new File(System.getProperty("test.classes"));
-        String[] args = {
-            "-d", ".",
+        // 7091528, tests if class files are being ignored
+        runTest("-d", ".",
             "-sourcepath", testClasses + File.pathSeparator + testSrc,
             "-subpackages",
-            "p"
-        };
+            "p");
+        // 8029145, tests if unique source files are parsed
+        runTest("-d", ".",
+            "-sourcepath", testSrc.getAbsolutePath(),
+            "-subpackages",
+            "p:p.q");
 
+    }
+    void runTest(String... args) {
         StringWriter sw = new StringWriter();
         PrintWriter pw = new PrintWriter(sw);
         String doclet = com.sun.tools.doclets.standard.Standard.class.getName();