feat: Fail on launcher-, reporter-, or preprocessor-load errors.

Fail out of karma if a launcher, reporter, or preprocessor fails to
load, after attempting to load each of them, and reporting errors for
each load error.

Closes karma-runner#855

lib/launcher.js

@@ -61,12 +61,13 @@ var Launcher = function (emitter, injector) {
         var browser = injector.createChild([locals], ['launcher:' + name]).get('launcher:' + name)
       } catch (e) {
         if (e.message.indexOf('No provider for "launcher:' + name + '"') !== -1) {
-          log.warn('Can not load "%s", it is not registered!\n  ' +
-            'Perhaps you are missing some plugin?', name)
+          log.error('Cannot load browser "%s": it is not registered! ' +
+                    'Perhaps you are missing some plugin?', name)
         } else {
-          log.warn('Can not load "%s"!\n  ' + e.stack, name)
+          log.error('Cannot load browser "%s"!\n  ' + e.stack, name)
         }
 
+        emitter.emit('load_error', 'launcher', name)
         return
       }
 

lib/preprocessor.js

@@ -36,13 +36,13 @@ var createNextProcessor = function (preprocessors, file, done) {
   }
 }
 
-var createPreprocessor = function (config, basePath, injector) {
-  var alreadyDisplayedWarnings = {}
+var createPreprocessor = function (config, basePath, injector, emitter) {
+  var alreadyDisplayedErrors = {}
   var instances = {}
   var patterns = Object.keys(config)
 
   var instantiatePreprocessor = function (name) {
-    if (alreadyDisplayedWarnings[name]) {
+    if (alreadyDisplayedErrors[name]) {
       return
     }
 
@@ -52,13 +52,13 @@ var createPreprocessor = function (config, basePath, injector) {
       p = injector.get('preprocessor:' + name)
     } catch (e) {
       if (e.message.indexOf('No provider for "preprocessor:' + name + '"') !== -1) {
-        log.warn('Can not load "%s", it is not registered!\n  ' +
-                 'Perhaps you are missing some plugin?', name)
+        log.error('Can not load "%s", it is not registered!\n  ' +
+          'Perhaps you are missing some plugin?', name)
       } else {
-        log.warn('Can not load "%s"!\n  ' + e.stack, name)
+        log.error('Can not load "%s"!\n  ' + e.stack, name)
       }
-
-      alreadyDisplayedWarnings[name] = true
+      alreadyDisplayedErrors[name] = true
+      emitter.emit('load_error', 'preprocessor', name)
     }
 
     return p
@@ -85,37 +85,40 @@ var createPreprocessor = function (config, basePath, injector) {
         var nextPreprocessor = createNextProcessor(preprocessors, file, done)
 
         for (var i = 0; i < patterns.length; i++) {
-          if (mm(file.originalPath, patterns[i], {dot: true})) {
-            if (thisFileIsBinary) {
-              log.warn('Ignoring preprocessing (%s) %s because it is a binary file.',
-                config[patterns[i]].join(', '), file.originalPath)
-            } else {
-              config[patterns[i]].forEach(function (name) {
-                var p = instances[name]
-                if (p == null) {
-                  p = instantiatePreprocessor(name)
-                }
-
-                if (p == null) {
-                  if (!alreadyDisplayedWarnings[name]) {
-                    alreadyDisplayedWarnings[name] = true
-                    log.warn('Failed to instantiate preprocessor %s', name)
-                  }
-                  return
-                }
-
-                instances[name] = p
-                preprocessors.push(p)
-              })
-            }
+          if (!mm(file.originalPath, patterns[i], {dot: true})) continue
+
+          if (thisFileIsBinary) {
+            log.warn('Ignoring preprocessing (%s) %s because it is a binary file.',
+              config[patterns[i]].join(', '), file.originalPath)
+            continue
           }
+
+          config[patterns[i]].forEach(function (name) {
+            var p = instances[name]
+
+            if (p == null) {
+              p = instantiatePreprocessor(name)
+            }
+
+            if (p == null) {
+              if (!alreadyDisplayedErrors[name]) {
+                alreadyDisplayedErrors[name] = true
+                log.error('Failed to instantiate preprocessor %s', name)
+                emitter.emit('load_error', 'preprocessor', name)
+              }
+              return
+            }
+
+            instances[name] = p
+            preprocessors.push(p)
+          })
         }
 
         nextPreprocessor(null, thisFileIsBinary ? buffer : buffer.toString())
       })
     })
   }
 }
-createPreprocessor.$inject = ['config.preprocessors', 'config.basePath', 'injector']
+createPreprocessor.$inject = ['config.preprocessors', 'config.basePath', 'injector', 'emitter']
 
 exports.createPreprocessor = createPreprocessor

lib/reporter.js

@@ -107,11 +107,12 @@ var createReporters = function (names, config, emitter, injector) {
       reporters.push(injector.createChild([locals], ['reporter:' + name]).get('reporter:' + name))
     } catch (e) {
       if (e.message.indexOf('No provider for "reporter:' + name + '"') !== -1) {
-        log.warn('Can not load "%s", it is not registered!\n  ' +
+        log.error('Can not load reporter "%s", it is not registered!\n  ' +
           'Perhaps you are missing some plugin?', name)
       } else {
-        log.warn('Can not load "%s"!\n  ' + e.stack, name)
+        log.error('Can not load "%s"!\n  ' + e.stack, name)
       }
+      emitter.emit('load_error', 'reporter', name)
       return
     }
     var color_name = name + '_color'

lib/server.js

@@ -51,6 +51,8 @@ var Server = function (cliOptions, done) {
 
   this.log = logger.create()
 
+  this.loadErrors = []
+
   var config = cfg.parseConfig(cliOptions.configFile, cliOptions)
 
   var modules = [{
@@ -135,6 +137,10 @@ Server.prototype._start = function (config, launcher, preprocess, fileList, webS
 
   self._fileList = fileList
 
+  self.on('load_error', function (type, name) {
+    self.loadErrors.push([type, name])
+  })
+
   config.frameworks.forEach(function (framework) {
     self._injector.get('framework:' + framework)
   })
@@ -175,6 +181,11 @@ Server.prototype._start = function (config, launcher, preprocess, fileList, webS
           singleRunDoneBrowsers[browserLauncher.id] = false
         })
       }
+
+      if (self.loadErrors.length > 0) {
+        self.log.info('At least one plugin failed to load. Stopping Karma.')
+        process.kill(process.pid, 'SIGINT')
+      }
     })
   }