Fix bug where output in config files was not honoured

...and make debugging where `settings`, `output`, and `plugins` come
from easier.

lib/configuration.js

@@ -48,25 +48,60 @@ var concat = Array.prototype.concat;
  * @param {Object} target - Configuration to merge into.
  * @param {Object} configuration - Configuration to merge
  *   from.
- * @param {boolean} [recursive] - Used internally no ensure
- *   the plug-in key is only escaped at root-level.
+ * @param {string} [source] - Used internally no map
+ *   changes to source files, and to ensure the plug-in
+ *   key is only escaped at root-level.
  * @return {Object} - `target`.
  */
-function merge(target, configuration, recursive) {
+function merge(target, configuration, source) {
     var key;
     var value;
     var index;
     var length;
     var result;
     var plugin;
+    var subvalue;
+
+    /**
+     * Log a message about setting a value.
+     *
+     * @param {string} message - Thing done.
+     * @param {string} key - Affected key.
+     * @param {*} [value] - Set value, if any.
+     */
+    function log(message, key, value) {
+        if (!source) {
+            return;
+        }
+
+        if (value) {
+            debug(message + ' `%s` to `%j` (from `%s`)', key, value, source);
+        } else {
+            debug(message + ' `%s` (from `%s`)', key, source);
+        }
+    }
+
+    /**
+     * Check if `value` is an object with keys.
+     *
+     * @param {*} value - Value to check.
+     * @return {boolean} - Whether `value` is an object with keys.
+     */
+    function filled(value) {
+        return value && typeof value === 'object' && Object.keys(value).length;
+    }
+
+    /*
+     * Walk `configuration`.
+     */
 
     for (key in configuration) {
         value = configuration[key];
         result = target[key];
 
-        if (key === PLUGIN_KEY && !recursive) {
+        if (key === PLUGIN_KEY && source) {
             if (!result) {
-                target[key] = result = {};
+                target[PLUGIN_KEY] = result = {};
             }
 
             if ('length' in value) {
@@ -77,30 +112,44 @@ function merge(target, configuration, recursive) {
                     plugin = value[index];
 
                     if (!(plugin in result)) {
+                        log('Configuring plug-in', plugin, {});
                         result[plugin] = {};
                     }
                 }
             } else {
                 for (plugin in value) {
-                    if (value[plugin] === false) {
+                    subvalue = value[plugin];
+
+                    if (subvalue === false) {
                         result[plugin] = false
+                        log('Turning off plug-in', key);
+                    } else if (!filled(result[plugin])) {
+                        result[plugin] = merge({}, subvalue || {});
+                        log('Configuring plug-in', plugin, result[plugin]);
+                    } else if (!filled(subvalue)) {
+                        log('Not reconfiguring plug-in', plugin);
                     } else {
-                        result[plugin] = merge(
-                            result[plugin] || {},
-                            value[plugin] || {},
-                            true
-                        );
+                        result[plugin] = merge(result[plugin], subvalue);
+                        log('Reconfiguring plug-in', plugin, result[plugin]);
                     }
                 }
             }
-        } else if (typeof value === 'object' && value !== null) {
+        } else if (value && typeof value === 'object') {
             if ('length' in value) {
                 target[key] = concat.apply(value);
-            } else {
-                target[key] = merge(result || {}, value, true);
+                log('Setting', key, target[key]);
+            } else if (filled(value)) {
+                if (result) {
+                    target[key] = merge(result, value);
+                    log('Merging', key, target[key]);
+                } else {
+                    target[key] = value;
+                    log('Setting', key, value);
+                }
             }
         } else if (value !== undefined) {
             target[key] = value;
+            log('Setting', key, target[key]);
         }
     }
 
@@ -137,10 +186,11 @@ function load(filePath) {
  * Get personal configuration object from `~`.
  * Loads `rcName` and `rcName.js`.
  *
+ * @param {Object} config - Config to load into.
  * @param {string?} rcName - Name of configuration file.
  * @return {Object} - Parsed JSON.
  */
-function getUserConfiguration(rcName) {
+function loadUserConfiguration(config, rcName) {
     var configuration = {};
 
     /**
@@ -152,7 +202,7 @@ function getUserConfiguration(rcName) {
         /* istanbul ignore next - not really testable
          * as this loads files outside this project. */
         if (exists(filePath)) {
-            merge(configuration, load(filePath));
+            merge(configuration, load(filePath), filePath);
         }
     }
 
@@ -228,13 +278,13 @@ function getLocalConfiguration(context, directory, callback) {
 
             debug('Using ' + file.filePath());
 
-            merge(configuration, local);
+            merge(configuration, local, file.filePath());
         }
 
         if (!found) {
             debug('Using personal configuration');
 
-            merge(configuration, getUserConfiguration(rcName));
+            loadUserConfiguration(configuration, rcName);
         }
 
         callback(err, configuration);
@@ -299,23 +349,20 @@ Configuration.prototype.getConfiguration = function (filePath, callback) {
      */
     function handleLocalConfiguration(err, localConfiguration) {
         var current = self.cache[directory];
+        var config = localConfiguration || {};
 
-        if (localConfiguration) {
-            merge(configuration, localConfiguration);
-        }
-
-        merge(configuration, self.rcFile);
+        merge(config, self.rcFile, self.settings.rcPath);
 
-        merge(configuration, {
+        merge(config, {
             'settings': self.settings.settings,
             'plugins': self.settings.plugins,
             'output': self.settings.output
-        });
+        }, 'settings');
 
-        self.cache[directory] = configuration;
+        self.cache[directory] = config;
 
         current.forEach(function (callback) {
-            callback(err, configuration);
+            callback(err, config);
         });
     }
 
@@ -334,7 +381,6 @@ Configuration.prototype.getConfiguration = function (filePath, callback) {
     }
 
     self.cache[directory] = [callback];
-    configuration = {};
     getLocalConfiguration(self, directory, handleLocalConfiguration);
 };
 

lib/index.js

@@ -97,7 +97,7 @@ function run(options, callback) {
 
     settings.streamOut = options.streamOut || process.stdout;
     settings.streamError = options.streamError || process.stderr;
-    settings.output = options.output || false;
+    settings.output = options.output || undefined;
     settings.out = options.out;
 
     if (settings.output && settings.out) {