Ensure that the javaOptions are set correctly, as exec is asynchronous.

Previously, the `java` command would execute on the next tick and update the
`javaOptions` array, which could occur prior to the invocation of the Closure
Compiler on the current tick. This has now been refactored into a separate
`getJavaOptions` function, which passes the `javaOptions` array to a callback.

`getJavaOptions` is defined lazily; after the first invocation, the options
are cached and passed to all subsequent callbacks. The callbacks are invoked
on the next tick for compatibility with `exec`.


Former-commit-id: 89ca63c9edb3df3d4fcbbaa64e06075495febfd0

build/minify.js

@@ -60,15 +60,30 @@
   }());
 
   /**
-   * Java command-line options used for faster minification.
+   * Retrieves the Java command-line options used for faster minification by
+   * the Closure Compiler, invoking the `callback` when finished. Subsequent
+   * invocations will lazily return the original options. The callback is
+   * invoked with one argument: `(javaOptions)`.
+   *
    * See https://code.google.com/p/closure-compiler/wiki/FAQ#What_are_the_recommended_Java_VM_command-line_options?.
+   *
+   * @param {Function} callback The function called once the options have
+   * been retrieved.
    */
+  function getJavaOptions(callback) {
     var javaOptions = [];
     cp.exec('java -version -client -d32', function(error) {
       if (!error && process.platform != 'win32') {
         javaOptions.push('-client', '-d32');
       }
+      getJavaOptions = function getJavaOptions(callback) {
+        process.nextTick(function () {
+          callback(javaOptions);
         });
+      };
+      callback(javaOptions);
+    });
+  }
 
   /** The Closure Compiler optimization modes */
   var optimizationModes = {
@@ -386,6 +401,8 @@
     if (isMapped) {
       options.push('--create_source_map=' + mapPath, '--source_map_format=V3');
     }
+
+    getJavaOptions(function onJavaOptions(javaOptions) {
       var compiler = cp.spawn('java', javaOptions.concat('-jar', closurePath, options));
       if (!this.isSilent) {
         console.log('Compressing ' + path.basename(outputPath, '.js') + ' using the Closure Compiler (' + mode + ')...');
@@ -437,6 +454,7 @@
 
       // proxy the standard input to the Closure Compiler
       compiler.stdin.end(source);
+    }.bind(this));
   }
 
   /**