8179373: javac -verbose logs the class path multiple times

Reviewed-by: martin

src/jdk.compiler/share/classes/com/sun/tools/javac/code/ClassFinder.java

@@ -633,6 +633,7 @@ public class ClassFinder {
         boolean haveSourcePath = includeSourcePath && fileManager.hasLocation(SOURCE_PATH);
 
         if (verbose && verbosePath) {
+            verbosePath = false; // print once per compile
             if (fileManager instanceof StandardJavaFileManager) {
                 StandardJavaFileManager fm = (StandardJavaFileManager)fileManager;
                 if (haveSourcePath && wantSourceFiles) {

test/langtools/tools/javac/jvm/VerboseClassPathTest.java

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2018, Google Inc. 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 8179373
+ * @summary javac -verbose logs the class path multiple times
+ * @modules jdk.compiler
+ * @run main VerboseClassPathTest
+ */
+
+import java.io.BufferedReader;
+import java.io.PrintWriter;
+import java.io.StringReader;
+import java.io.StringWriter;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.spi.ToolProvider;
+
+public class VerboseClassPathTest {
+    public static void main(String... args) throws Exception {
+        new VerboseClassPathTest().run();
+    }
+
+    void run() throws Exception {
+        String className = getClass().getName();
+        Path testSrc = Paths.get(System.getProperty("test.src"));
+        Path file = testSrc.resolve(className + ".java");
+        ToolProvider javac = ToolProvider.findFirst("javac").orElseThrow();
+        StringWriter sw = new StringWriter();
+        PrintWriter pw = new PrintWriter(sw, true);
+        int rc =
+                javac.run(
+                        pw,
+                        pw,
+                        "-d",
+                        ",",
+                        "-source",
+                        "8",
+                        "-target",
+                        "8",
+                        "-verbose",
+                        file.toString());
+        String log = sw.toString();
+        System.out.println(log);
+        if (rc != 0) {
+            throw new Exception("compilation failed: rc=" + rc);
+        }
+        String expect = "[search path for class files:";
+        long count =
+                new BufferedReader(new StringReader(log))
+                        .lines()
+                        .filter(line -> line.startsWith(expect))
+                        .count();
+        if (count != 1) {
+            throw new Exception("expected '" + expect + "' to appear once, actual: " + count);
+        }
+    }
+}