8191078: Wrong "Package not found" warning

Reviewed-by: jjg, jlahoda

src/jdk.compiler/share/classes/com/sun/tools/javac/model/JavacElements.java

@@ -197,9 +197,18 @@ public class JavacElements implements Elements {
         for (ModuleSymbol msym : modules.allModules()) {
             S sym = nameToSymbol(msym, nameStr, clazz);
 
-            if (sym != null) {
-                if (!allowModules || clazz == ClassSymbol.class || !sym.members().isEmpty()) {
-                    //do not add packages without members:
+            if (sym == null)
+                continue;
+
+            if (clazz == ClassSymbol.class) {
+                // Always include classes
+                found.add(sym);
+            } else if (clazz == PackageSymbol.class) {
+                // In module mode, ignore the "spurious" empty packages that "enclose" module-specific packages.
+                // For example, if a module contains classes or package info in package p.q.r, it will also appear
+                // to have additional packages p.q and p, even though these packages have no content other
+                // than the subpackage.  We don't want those empty packages showing up in searches for p or p.q.
+                if (!sym.members().isEmpty() || ((PackageSymbol) sym).package_info != null) {
                     found.add(sym);
                 }
             }

test/langtools/jdk/javadoc/tool/testPackages/TestPackages.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2017, 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
+ * 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 8191078
+ * @summary ensure that javadoc considers packages correctly
+ * @modules jdk.javadoc/jdk.javadoc.internal.tool
+ *          jdk.compiler/com.sun.tools.javac.api
+ *          jdk.compiler/com.sun.tools.javac.main
+ *          jdk.javadoc/jdk.javadoc.internal.api
+ *          jdk.javadoc/jdk.javadoc.internal.tool
+ * @library /tools/lib
+ * @build toolbox.JavadocTask toolbox.TestRunner toolbox.ToolBox
+ * @run main TestPackages
+ */
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.List;
+
+import toolbox.*;
+import toolbox.Task.Expect;
+import toolbox.Task.OutputKind;
+import toolbox.Task.Result;
+
+public class TestPackages extends TestRunner {
+
+    final ToolBox tb = new ToolBox();
+
+    public TestPackages() {
+        super(System.err);
+    }
+
+    public static void main(String[] args) throws Exception {
+        TestPackages t = new TestPackages();
+        t.runTests(m -> new Object[] { Paths.get(m.getName()) });
+    }
+
+    @Test
+    public void testEmptyPackage(Path base) throws Exception {
+        Files.createDirectories(base);
+        tb.writeFile(base.resolve("p1/package-info.java"), "package p1;\n");
+        tb.writeFile(base.resolve("p2/A.java"), "package p2;\npublic class A {}\n");
+
+        Path outDir = base.resolve("out");
+        Files.createDirectory(outDir);
+        JavadocTask task = new JavadocTask(tb);
+        task = task.outdir(outDir).sourcepath(base).options("p1", "p2");
+        Result r = task.run(Expect.SUCCESS);
+        List<String> list = tb.grep(".*warning.*not found.*", r.getOutputLines(OutputKind.DIRECT));
+        if (!list.isEmpty()) {
+            throw new Exception("Found warning: " + list.get(0));
+        }
+    }
+}