Merge branch '2.7' into 2.8

* 2.7:
  [travis] Test on PHP 7.1
  [FrameworkBundle] Convert null prefix to an empty string in translation:update command

Author: nicolas-grekas

.travis.yml

@@ -28,7 +28,7 @@ matrix:
         - php: 5.6
         - php: 7.0
           env: deps=high
-        - php: 7.0
+        - php: 7.1
           env: deps=low
     fast_finish: true
 
@@ -52,7 +52,7 @@ before_install:
     - if [[ ! $skip && $PHP = 5.* ]]; then echo extension = mongo.so >> $INI_FILE; fi
     - if [[ ! $skip && $PHP = 5.* ]]; then echo extension = memcache.so >> $INI_FILE; fi
     - if [[ ! $skip && $PHP = 5.* ]]; then (echo yes | pecl install -f apcu-4.0.11 && echo apc.enable_cli = 1 >> $INI_FILE); fi
-    - if [[ ! $skip && $PHP = 7.0 ]]; then (echo yes | pecl install -f apcu-5.1.5 && echo apc.enable_cli = 1 >> $INI_FILE); fi
+    - if [[ ! $skip && $PHP = 7.* ]]; then (echo yes | pecl install -f apcu-5.1.6 && echo apc.enable_cli = 1 >> $INI_FILE); fi
     - if [[ ! $deps && $PHP = 5.* ]]; then (cd src/Symfony/Component/Debug/Resources/ext && phpize && ./configure && make && echo extension = $(pwd)/modules/symfony_debug.so >> $INI_FILE); fi
     - if [[ ! $skip && $PHP = 5.* ]]; then pecl install -f memcached-2.1.0; fi
     - if [[ ! $skip && ! $PHP = hhvm* ]]; then echo extension = ldap.so >> $INI_FILE; fi

src/Symfony/Bundle/FrameworkBundle/Command/TranslationUpdateCommand.php

@@ -119,8 +119,9 @@ protected function execute(InputInterface $input, OutputInterface $output)
         // load any messages from templates
         $extractedCatalogue = new MessageCatalogue($input->getArgument('locale'));
         $io->comment('Parsing templates...');
+        $prefix = $input->getOption('prefix');
         $extractor = $this->getContainer()->get('translation.extractor');
-        $extractor->setPrefix($input->getOption('prefix'));
+        $extractor->setPrefix(null === $prefix ? '' : $prefix);
         foreach ($transPaths as $path) {
             $path .= 'views';
             if (is_dir($path)) {