[Yaml] added support for parsing PHP constants

src/Symfony/Component/Yaml/CHANGELOG.md

@@ -1,6 +1,15 @@
 CHANGELOG
 =========
 
+3.2.0
+-----
+
+ * Added support for parsing PHP constants:
+
+   ```php
+   Yaml::parse('!php/const:PHP_INT_MAX', Yaml::PARSE_CONSTANT);
+   ```
+
 3.1.0
 -----
 

src/Symfony/Component/Yaml/Inline.php

@@ -28,6 +28,7 @@ class Inline
     private static $exceptionOnInvalidType = false;
     private static $objectSupport = false;
     private static $objectForMap = false;
+    private static $constantSupport = false;
 
     /**
      * Converts a YAML string to a PHP array.
@@ -77,6 +78,7 @@ public static function parse($value, $flags = 0, $references = array())
         self::$exceptionOnInvalidType = (bool) (Yaml::PARSE_EXCEPTION_ON_INVALID_TYPE & $flags);
         self::$objectSupport = (bool) (Yaml::PARSE_OBJECT & $flags);
         self::$objectForMap = (bool) (Yaml::PARSE_OBJECT_FOR_MAP & $flags);
+        self::$constantSupport = (bool) (Yaml::PARSE_CONSTANT & $flags);
 
         $value = trim($value);
 
@@ -580,6 +582,19 @@ private static function evaluateScalar($scalar, $flags, $references = array())
                             throw new ParseException('Object support when parsing a YAML file has been disabled.');
                         }
 
+                        return;
+                    case 0 === strpos($scalar, '!php/const:'):
+                        if (self::$constantSupport) {
+                            if (defined($const = substr($scalar, 11))) {
+                                return constant($const);
+                            }
+
+                            throw new ParseException(sprintf('The constant "%s" is not defined.', $const));
+                        }
+                        if (self::$exceptionOnInvalidType) {
+                            throw new ParseException(sprintf('The string "%s" could not be parsed as a constant. Have you forgotten to pass the "Yaml::PARSE_CONSTANT" flag to the parser?', $scalar));
+                        }
+
                         return;
                     case 0 === strpos($scalar, '!!float '):
                         return (float) substr($scalar, 8);

src/Symfony/Component/Yaml/Tests/InlineTest.php

@@ -35,6 +35,44 @@ public function testParseWithMapObjects($yaml, $value)
         $this->assertSame(serialize($value), serialize($actual));
     }
 
+    /**
+     * @dataProvider getTestsForParsePhpConstants
+     */
+    public function testParsePhpConstants($yaml, $value)
+    {
+        $actual = Inline::parse($yaml, Yaml::PARSE_CONSTANT);
+
+        $this->assertSame($value, $actual);
+    }
+
+    public function getTestsForParsePhpConstants()
+    {
+        return array(
+            array('!php/const:Symfony\Component\Yaml\Yaml::PARSE_CONSTANT', Yaml::PARSE_CONSTANT),
+            array('!php/const:PHP_INT_MAX', PHP_INT_MAX),
+            array('[!php/const:PHP_INT_MAX]', array(PHP_INT_MAX)),
+            array('{ foo: !php/const:PHP_INT_MAX }', array('foo' => PHP_INT_MAX)),
+        );
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Yaml\Exception\ParseException
+     * @expectedExceptionMessage The constant "WRONG_CONSTANT" is not defined
+     */
+    public function testParsePhpConstantThrowsExceptionWhenUndefined()
+    {
+        Inline::parse('!php/const:WRONG_CONSTANT', Yaml::PARSE_CONSTANT);
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Yaml\Exception\ParseException
+     * @expectedExceptionMessageRegExp #The string "!php/const:PHP_INT_MAX" could not be parsed as a constant.*#
+     */
+    public function testParsePhpConstantThrowsExceptionOnInvalidType()
+    {
+        Inline::parse('!php/const:PHP_INT_MAX', Yaml::PARSE_EXCEPTION_ON_INVALID_TYPE);
+    }
+
     /**
      * @group legacy
      * @dataProvider getTestsForParseWithMapObjects

src/Symfony/Component/Yaml/Yaml.php

@@ -28,6 +28,7 @@ class Yaml
     const PARSE_DATETIME = 32;
     const DUMP_OBJECT_AS_MAP = 64;
     const DUMP_MULTI_LINE_LITERAL_BLOCK = 128;
+    const PARSE_CONSTANT = 256;
 
     /**
      * Parses YAML into a PHP value.