Add support for accessing class constants with the dot operator

CHANGELOG

@@ -1,5 +1,6 @@
 # 3.15.0 (2024-XX-XX)
 
+ * Add support for accessing class constants with the dot operator
  * Add `Profile::getStartTime()` and `Profile::getEndTime()`
  * Fix "ignore missing" when used on an "embed" tag
  * Fix the possibility to override an aliased block (via use)

doc/templates.rst

@@ -76,8 +76,8 @@ Twig templates have access to variables provided by the PHP application and
 variables created in templates via the :doc:`set <tags/set>` tag. These
 variables can be manipulated and displayed in the template.
 
-Use a dot (``.``) to access attributes of a variable (methods or properties of a
-PHP object, or items of a PHP array):
+Use a dot (``.``) to access attributes of a variable (methods, properties
+or constants of a PHP object, or items of a PHP array):
 
 .. code-block:: twig
 
@@ -767,8 +767,8 @@ The following operators don't fit into any of the other categories:
 
 * ``.``, ``[]``: Gets an attribute of a variable.
 
-  The (``.``) operator abstracts getting an attribute of a variable (methods
-  or properties of a PHP object, or items of a PHP array):
+  The (``.``) operator abstracts getting an attribute of a variable (methods,
+ properties or constants of a PHP object, or items of a PHP array):
 
   .. code-block:: twig
 
@@ -803,6 +803,7 @@ The following operators don't fit into any of the other categories:
       * check if ``user`` is a PHP array or a ArrayObject/ArrayAccess object and
         ``name`` a valid element;
       * if not, and if ``user`` is a PHP object, check that ``name`` is a valid property;
+      * if not, and if ``user`` is a PHP object, check that ``name`` is a class constant;
       * if not, and if ``user`` is a PHP object, check the following methods and
         call the first valid one: ``name()``, ``getName()``, ``isName()``, or
         ``hasName()``;

src/Extension/CoreExtension.php

@@ -1675,6 +1675,18 @@ final class CoreExtension extends AbstractExtension
 
                 return $object->$item;
             }
+
+            if (\defined($object::class.'::'.$item)) {
+                if ($isDefinedTest) {
+                    return true;
+                }
+
+                if ($sandboxed) {
+                    $env->getExtension(SandboxExtension::class)->checkPropertyAllowed($object, $item, $lineno, $source);
+                }
+
+                return \constant($object::class.'::'.$item);
+            }
         }
 
         static $cache = [];

tests/Fixtures/expressions/const.test

@@ -0,0 +1,10 @@
+--TEST--
+Twig supports accessing constants
+--TEMPLATE--
+{{ foo.BAR_NAME }}
+--DATA--
+return ['foo' => new Twig\Tests\TwigTestFoo()]
+--CONFIG--
+return ['strict_variables' => false]
+--EXPECT--
+bar