[5.4] Implement standalone if empty in a NB-Change-Way (#18738)

* 5.4 Implement if empty in as NB-Change

* Fix little StyleCI Issue

* Fix little StyleCI Issue #2

* Fix little StyleCI Issue #3

* Update CompilesLoops.php

Author: Lukas Kämmerling

src/Illuminate/View/Compilers/Concerns/CompilesLoops.php

@@ -35,12 +35,17 @@ protected function compileForelse($expression)
     }
 
     /**
-     * Compile the for-else-empty statements into valid PHP.
+     * Compile the for-else-empty and empty statements into valid PHP.
      *
+     * @param  string  $expression
      * @return string
      */
-    protected function compileEmpty()
+    protected function compileEmpty($expression)
     {
+        if ($expression) {
+            return "<?php if(empty{$expression}): ?>";
+        }
+
         $empty = '$__empty_'.$this->forElseCounter--;
 
         return "<?php endforeach; \$__env->popLoop(); \$loop = \$__env->getLastLoop(); if ({$empty}): ?>";
@@ -56,6 +61,16 @@ protected function compileEndforelse()
         return '<?php endif; ?>';
     }
 
+    /**
+     * Compile the end-empty statements into valid PHP.
+     *
+     * @return string
+     */
+    protected function compileEndEmpty()
+    {
+        return '<?php endif; ?>';
+    }
+
     /**
      * Compile the for statements into valid PHP.
      *

tests/View/Blade/BladeIfIEmptyStatementsTest.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace Illuminate\Tests\Blade;
+
+use Mockery as m;
+use PHPUnit\Framework\TestCase;
+use Illuminate\View\Compilers\BladeCompiler;
+
+class BladeIfEmptyStatementsTest extends TestCase
+{
+    public function tearDown()
+    {
+        m::close();
+    }
+
+    public function testIfStatementsAreCompiled()
+    {
+        $compiler = new BladeCompiler($this->getFiles(), __DIR__);
+        $string = '@empty ($test)
+breeze
+@endempty';
+        $expected = '<?php if(empty($test)): ?>
+breeze
+<?php endif; ?>';
+        $this->assertEquals($expected, $compiler->compileString($string));
+    }
+
+    protected function getFiles()
+    {
+        return m::mock('Illuminate\Filesystem\Filesystem');
+    }
+}