Fix conversion of ICU 'L' symbol.

L should not contain a leading zero.
Added a test for this too.

close #7761

framework/CHANGELOG.md

@@ -14,6 +14,7 @@ Yii Framework 2 Change Log
 - Bug #7603: Fixed escape characters in `FormatConverter` to work with unicode characters (maddoger, cebe)
 - Bug #7656: Fixed `yii\rbac\DbManager::getRolesByUser()` and `yii\rbac\PhpManager::getRolesByUser()` to return roles only (samdark)
 - Bug #7757: Fix fetching tables schema for oci and mysql when PDO::ATTR_CASE is set (nineinchnick)
+- Bug #7761: Fixed formatting one digit month in date formatter using ICU format `L` (nkovacs)
 - Bug #7775: Added more strict check on controller IDs when they are being used to create controller instances on Windows (Bhoft, qiangxue)
 - Bug #7831: Add order when fetching database table names and constraints (nineinchnick)
 - Bug #7846: Fixed `yii\base\Model` does not recognize scenario declared by rules using 'except' (klimov-paul)

framework/helpers/BaseFormatConverter.php

@@ -153,7 +153,7 @@ class BaseFormatConverter
             'MMM' => 'M',   // A short textual representation of a month, three letters
             'MMMM' => 'F',  // A full textual representation of a month, such as January or March
             'MMMMM' => '',  //
-            'L' => 'm',     // Stand alone month in year
+            'L' => 'n',     // Stand alone month in year
             'LL' => 'm',    // Stand alone month in year
             'LLL' => 'M',   // Stand alone month in year
             'LLLL' => 'F',  // Stand alone month in year
@@ -363,7 +363,7 @@ class BaseFormatConverter
             'MMM' => 'M',   // A short textual representation of a month, three letters
             'MMMM' => 'MM', // A full textual representation of a month, such as January or March
             'MMMMM' => '',  //
-            'L' => 'mm',     // Stand alone month in year
+            'L' => 'm',     // Stand alone month in year
             'LL' => 'mm',   // Stand alone month in year
             'LLL' => 'M',   // Stand alone month in year
             'LLLL' => 'MM', // Stand alone month in year

tests/framework/helpers/FormatConverterTest.php

@@ -55,6 +55,7 @@ class FormatConverterTest extends TestCase
         $formatter = new Formatter(['locale' => 'en-US']);
         $this->assertEquals('24.8.2014', $formatter->asDate('2014-8-24', 'php:d.n.Y'));
         $this->assertEquals('24.8.2014', $formatter->asDate('2014-8-24', 'd.M.yyyy'));
+        $this->assertEquals('24.8.2014', $formatter->asDate('2014-8-24', 'd.L.yyyy'));
     }
 
     public function testOneDigitIcu()
@@ -62,6 +63,7 @@ class FormatConverterTest extends TestCase
         $formatter = new Formatter(['locale' => 'en-US']);
         $this->assertEquals('24.8.2014', $formatter->asDate('2014-8-24', 'php:d.n.Y'));
         $this->assertEquals('24.8.2014', $formatter->asDate('2014-8-24', 'd.M.yyyy'));
+        $this->assertEquals('24.8.2014', $formatter->asDate('2014-8-24', 'd.L.yyyy'));
     }
 
     public function testIntlUtf8Ru()