ensure last dir is not skipped if name is '0', fixes #131

A check with emptyh('0') returns true, which then skips creation of the
last directory. Thus, the check must be explicitly for a string and it's
length.

CHANGELOG.md

@@ -1,3 +1,9 @@
+1.6.3 (2016-04-09)
+------------------
+
+   * fixed #131 recursive mkdir() fails if the last dirname is '0'
+
+
 1.6.2 (2016-01-13)
 ------------------
 

src/main/php/org/bovigo/vfs/vfsStream.php

@@ -358,7 +358,7 @@ public static function newDirectory($name, $permissions = null)
         $ownName   = substr($name, 0, $firstSlash);
         $subDirs   = substr($name, $firstSlash + 1);
         $directory = new vfsStreamDirectory($ownName, $permissions);
-        if (!empty($subDirs)) {
+        if (is_string($subDirs) && strlen($subDirs) > 0) {
             self::newDirectory($subDirs, $permissions)->at($directory);
         }
 

src/test/php/org/bovigo/vfs/vfsStreamWrapperDirTestCase.php

@@ -249,6 +249,19 @@ public function mkDirShouldNotOverwriteExistingFilesAndTriggerE_USER_WARNING()
         $this->assertFalse(mkdir(vfsStream::url('root/test.txt')));
     }
 
+    /**
+     * @test
+     * @group  issue_131
+     * @since  1.6.3
+     */
+    public function allowsRecursiveMkDirWithDirectoryName0()
+    {
+        vfsStream::setup('root');
+        $subdir  = vfsStream::url('root/a/0');
+        mkdir($subdir, 0777, true);
+        $this->assertFileExists($subdir);
+    }
+
     /**
      * @test
      * @group  permissions