Merge branch '3.4' into 4.0

* 3.4: (22 commits)
  fix merge
  [Translation] Fix InvalidArgumentException when using untranslated plural forms from .po files
  Fixed exit code with non-integer throwable code
  [HttpFoundation] Support 0 bit netmask in IPv6 ()
  [DI] Impossible to set an environment variable and then an array as container parameter
  [Process] remove false-positive BC breaking exception on Windows
  Tweaking class not found autowiring error
  [LDAP] added missing dots at the end of some exception messages.
  [TwigBridge] Add missing dev requirement for workflow
  fixed #25440
  empty lines don't count for indent detection
  Set `width: auto` on WebProfiler toolbar's reset.
  [Lock] Fix incorrect phpdoc
  [Process] Dont rely on putenv(), it fails on ZTS PHP
  [HttpKernel] detect deprecations thrown by container initialization during tests
  [HttpKernel] Fix logging of post-terminate errors/exceptions
  [DI] Add context to service-not-found exceptions thrown by service locators
  [Debug] Fix catching fatal errors in case of nested error handlers
  [VarDumper] Fixed file links leave blank pages when ide is configured
  Fix hidden currency element with Bootstrap 3 theme
  ...

Author: nicolas-grekas

MessageSelector.php

@@ -49,10 +49,16 @@ class MessageSelector
      */
     public function choose($message, $number, $locale)
     {
-        preg_match_all('/(?:\|\||[^\|])++/', $message, $parts);
+        $parts = array();
+        if (preg_match('/^\|++$/', $message)) {
+            $parts = explode('|', $message);
+        } elseif (preg_match_all('/(?:\|\||[^\|])++/', $message, $matches)) {
+            $parts = $matches[0];
+        }
+
         $explicitRules = array();
         $standardRules = array();
-        foreach ($parts[0] as $part) {
+        foreach ($parts as $part) {
             $part = trim(str_replace('||', '|', $part));
 
             if (preg_match('/^(?P<interval>'.Interval::getIntervalRegexp().')\s*(?P<message>.*?)$/xs', $part, $matches)) {
@@ -76,7 +82,7 @@ public function choose($message, $number, $locale)
         if (!isset($standardRules[$position])) {
             // when there's exactly one rule given, and that rule is a standard
             // rule, use this rule
-            if (1 === count($parts[0]) && isset($standardRules[0])) {
+            if (1 === count($parts) && isset($standardRules[0])) {
                 return $standardRules[0];
             }
 

Tests/MessageSelectorTest.php

@@ -128,6 +128,10 @@ public function getChooseTests()
             array("This is a text with a\nnew-line in it. Selector = 1.", "{0}This is a text with a\nnew-line in it. Selector = 0.|{1}This is a text with a\nnew-line in it. Selector = 1.|[1,Inf]This is a text with a\nnew-line in it. Selector > 1.", 1),
             // esacape pipe
             array('This is a text with | in it. Selector = 0.', '{0}This is a text with || in it. Selector = 0.|{1}This is a text with || in it. Selector = 1.', 0),
+            // Empty plural set (2 plural forms) from a .PO file
+            array('', '|', 1),
+            // Empty plural set (3 plural forms) from a .PO file
+            array('', '||', 1),
         );
     }
 }