8234211: allow discoverable javac plugins to be invoked by default

Reviewed-by: jlahoda

src/jdk.compiler/share/classes/com/sun/source/util/Plugin.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2019, 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
@@ -62,4 +62,20 @@ public interface Plugin {
      * @param args Arguments, if any, for the plug-in
      */
     void init(JavacTask task, String... args);
+
+    /**
+     * Returns whether or not this plugin should be automatically started,
+     * even if not explicitly specified in the command-line options.
+     *
+     * <p>This method will be called by javac for all plugins located by the
+     * service loader. If the method returns {@code true}, the plugin will be
+     * {@link #init(JavacTask,String[]) initialized} with an empty array of
+     * string arguments if it is not otherwise initialized due to an explicit
+     * command-line option.
+     *
+     * @return whether or not this plugin should be automatically started
+     */
+    default boolean autoStart() {
+        return false;
+    }
 }

src/jdk.compiler/share/classes/com/sun/tools/javac/api/BasicJavacTask.java

@@ -208,16 +208,18 @@ public class BasicJavacTask extends JavacTask {
             }
         }
 
-        if (pluginOpts.isEmpty())
-            return;
-
         Set<List<String>> pluginsToCall = new LinkedHashSet<>(pluginOpts);
         JavacProcessingEnvironment pEnv = JavacProcessingEnvironment.instance(context);
         ServiceLoader<Plugin> sl = pEnv.getServiceLoader(Plugin.class);
+        Set<Plugin> autoStart = new LinkedHashSet<>();
         for (Plugin plugin : sl) {
+            if (plugin.autoStart()) {
+                autoStart.add(plugin);
+            }
             for (List<String> p : pluginsToCall) {
                 if (plugin.getName().equals(p.head)) {
                     pluginsToCall.remove(p);
+                    autoStart.remove(plugin);
                     try {
                         plugin.init(this, p.tail.toArray(new String[p.tail.size()]));
                     } catch (RuntimeException ex) {
@@ -230,6 +232,14 @@ public class BasicJavacTask extends JavacTask {
         for (List<String> p: pluginsToCall) {
             Log.instance(context).error(Errors.PluginNotFound(p.head));
         }
+        for (Plugin plugin : autoStart) {
+            try {
+                plugin.init(this, new String[0]);
+            } catch (RuntimeException ex) {
+                throw new PropagatedException(ex);
+            }
+
+        }
     }
 
     public void initDocLint(List<String> docLintOpts) {

src/jdk.compiler/share/classes/com/sun/tools/javac/main/Main.java

@@ -284,12 +284,11 @@ public class Main {
             Dependencies.GraphDependencies.preRegister(context);
         }
 
+        BasicJavacTask t = (BasicJavacTask) BasicJavacTask.instance(context);
+
         // init plugins
         Set<List<String>> pluginOpts = args.getPluginOpts();
-        if (!pluginOpts.isEmpty() || context.get(PlatformDescription.class) != null) {
+        t.initPlugins(pluginOpts);
-            BasicJavacTask t = (BasicJavacTask) BasicJavacTask.instance(context);
-            t.initPlugins(pluginOpts);
-        }
 
         // init multi-release jar handling
         if (fileManager.isSupportedOption(Option.MULTIRELEASE.primaryName) == 1) {
@@ -304,7 +303,6 @@ public class Main {
         // init doclint
         List<String> docLintOpts = args.getDocLintOpts();
         if (!docLintOpts.isEmpty()) {
-            BasicJavacTask t = (BasicJavacTask) BasicJavacTask.instance(context);
             t.initDocLint(docLintOpts);
         }
 

test/langtools/tools/javac/plugin/AutostartPlugins.java

@@ -0,0 +1,175 @@
+/*
+ * Copyright (c) 2018, 2019, 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 8234211
+ *  @summary allow discoverable javac plugins to be invoked by default
+ *  @library /tools/lib
+ *  @modules jdk.compiler/com.sun.tools.javac.api
+ *           jdk.compiler/com.sun.tools.javac.main
+ *           jdk.jlink
+ *  @build toolbox.ToolBox toolbox.JavacTask toolbox.JarTask
+ *  @run main AutostartPlugins
+ */
+
+import java.io.IOException;
+import java.util.List;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.spi.ToolProvider;
+
+import toolbox.ExecTask;
+import toolbox.JarTask;
+import toolbox.JavacTask;
+import toolbox.Task;
+import toolbox.TestRunner;
+import toolbox.ToolBox;
+
+public class AutostartPlugins extends TestRunner {
+    public static void main(String... args) throws Exception {
+        new AutostartPlugins().run();
+    }
+
+    AutostartPlugins() {
+        super(System.out);
+    }
+
+    ToolBox tb = new ToolBox();
+
+    Path pluginJar;
+    Path mclasses;
+
+    void run() throws Exception {
+        Path src = Path.of("src");
+        tb.writeJavaFiles(src,
+            "package p;\n"
+            + "import com.sun.source.util.*;\n"
+            + "public class C implements Plugin {\n"
+            + "    public String getName() { return \"TestPlugin\"; }\n"
+            + "    public boolean autoStart() { return true; }\n"
+            + "    public void init(JavacTask task, String... args) {\n"
+            + "        System.out.println(\"C.init \" + java.util.Arrays.toString(args));\n"
+            + "    }\n"
+            + "}\n");
+
+        Path msrc = Path.of("msrc");
+        tb.writeJavaFiles(msrc,
+            "module m {\n"
+            + "    requires jdk.compiler;\n"
+            + "    provides com.sun.source.util.Plugin with p.C;\n"
+            + "}\n");
+
+        Path classes = Files.createDirectories(Path.of("classes"));
+        new JavacTask(tb)
+            .outdir(classes)
+            .files(tb.findJavaFiles(src))
+            .run()
+            .writeAll();
+
+        tb.writeFile(classes.resolve("META-INF").resolve("services").resolve("com.sun.source.util.Plugin"),
+                "p.C\n");
+
+        pluginJar = Path.of("plugin.jar");
+        new JarTask(tb, pluginJar)
+                .baseDir(classes)
+                .files(".")
+                .run();
+
+        mclasses = Files.createDirectories(Path.of("mclasses"));
+        new JavacTask(tb)
+            .outdir(mclasses)
+            .sourcepath(msrc, src)
+            .files(tb.findJavaFiles(msrc))
+            .run()
+            .writeAll();
+
+        Path hw = Path.of("hw");
+        tb.writeJavaFiles(hw,
+                "public class HelloWorld {\n"
+                + "    public static void main(String... args) {\n"
+                + "        System.out.println(\"Hello World!\");\n"
+                + "    }\n"
+                + "}\n");
+
+        runTests(m -> new Object[] { Path.of(m.getName()) });
+    }
+
+    @Test
+    public void testClassPath(Path base) throws Exception {
+        List<String> stdout = new JavacTask(tb)
+                .classpath(pluginJar)
+                .outdir(Files.createDirectories(base.resolve("out")))
+                .files(tb.findJavaFiles(Path.of("hw")))
+                .run()
+                .writeAll()
+                .getOutputLines(Task.OutputKind.STDOUT);
+        tb.checkEqual(stdout, List.of("C.init []"));
+    }
+
+    @Test
+    public void testModulePath(Path base) throws IOException {
+        List<String> stdout = new JavacTask(tb)
+                .options("--processor-module-path", mclasses.toString())
+                .outdir(Files.createDirectories(base.resolve("out")))
+                .files(tb.findJavaFiles(Path.of("hw")))
+                .run()
+                .writeAll()
+                .getOutputLines(Task.OutputKind.STDOUT);
+        tb.checkEqual(stdout, List.of("C.init []"));
+    }
+
+    @Test
+    public void testImage(Path base) throws Exception {
+        Path tmpJDK = base.resolve("tmpJDK");
+        ToolProvider jlink = ToolProvider.findFirst("jlink")
+                .orElseThrow(() -> new Exception("cannot find jlink"));
+        jlink.run(System.out, System.err,
+                "--module-path", mclasses.toString(),
+                "--add-modules", "jdk.compiler,jdk.zipfs,m",
+                "--output", tmpJDK.toString());
+
+        String suffix = tb.isWindows() ? ".exe" : "";
+        List<String> stdout = new ExecTask(tb, tmpJDK.resolve("bin").resolve("javac" + suffix))
+                .args("-d", Files.createDirectories(base.resolve("out")).toString(),
+                        Path.of("hw").resolve("HelloWorld.java").toString())
+                .run()
+                .writeAll()
+                .getOutputLines(Task.OutputKind.STDOUT);
+        tb.checkEqual(stdout, List.of("C.init []"));
+    }
+
+    @Test
+    public void testOverride(Path base) throws IOException {
+        List<String> stdout = new JavacTask(tb)
+                .classpath(pluginJar)
+                .outdir(Files.createDirectories(base.resolve("out")))
+                .options("-Xplugin:TestPlugin -args")
+                .files(tb.findJavaFiles(Path.of("hw")))
+                .run()
+                .writeAll()
+                .getOutputLines(Task.OutputKind.STDOUT);
+        tb.checkEqual(stdout, List.of("C.init [-args]"));
+    }
+}
+