Fixed twig {{ false|string }} to return '0' instead of ''

CHANGELOG.md

@@ -10,6 +10,7 @@
     * Fixed PHP 7.4 compatibility issue with `Stream`
     * Fixed new `Flex Users` being stored with wrong filename, login issues [#2785](https://github.com/getgrav/grav/issues/2785)
     * Fixed `ignore_empty: true` not removing empty values in blueprint filtering
+    * Fixed twig `{{ false|string }}` to return '0' instead of ''
 
 # v1.7.0-rc.3
 ## 01/02/2020

system/src/Grav/Common/Twig/TwigExtension.php

@@ -167,7 +167,7 @@ class TwigExtension extends AbstractExtension implements GlobalsInterface
             new TwigFunction('repeat', [$this, 'repeatFunc']),
             new TwigFunction('regex_replace', [$this, 'regexReplace']),
             new TwigFunction('regex_filter', [$this, 'regexFilter']),
-            new TwigFunction('string', [$this, 'stringFunc']),
+            new TwigFunction('string', [$this, 'stringFilter']),
             new TwigFunction('url', [$this, 'urlFunc']),
             new TwigFunction('json_decode', [$this, 'jsonDecodeFilter']),
             new TwigFunction('get_cookie', [$this, 'getCookie']),
@@ -689,14 +689,25 @@ class TwigExtension extends AbstractExtension implements GlobalsInterface
     }
 
     /**
-     * Casts input to string.
+     * Returns a string from a value. If the value is array, return it json encoded
      *
-     * @param mixed $input
+     * @param mixed $value
      * @return string
      */
-    public function stringFilter($input)
+    public function stringFilter($value)
     {
-        return (string) $input;
+        // Format the array as a string
+        if (is_array($value)) {
+            return json_encode($value);
+        }
+
+        // Boolean becomes '1' or '0'
+        if (is_bool($value)) {
+            $value = (int)$value;
+        }
+
+        // Cast the other values to string.
+        return (string)$value;
     }
 
     /**
@@ -992,22 +1003,6 @@ class TwigExtension extends AbstractExtension implements GlobalsInterface
         return array_intersect($array1, $array2);
     }
 
-    /**
-     * Returns a string from a value. If the value is array, return it json encoded
-     *
-     * @param array|string $value
-     *
-     * @return string
-     */
-    public function stringFunc($value)
-    {
-        if (is_array($value)) { //format the array as a string
-            return json_encode($value);
-        }
-
-        return $value;
-    }
-
     /**
      * Translate a string
      *