feature symfony#18626 [Yaml] Added support for parsing PHP constants (HeahDude)

This PR was merged into the 3.2-dev branch.

Discussion
----------

[Yaml] Added support for parsing PHP constants

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | ~
| License       | MIT
| Doc PR        | TODO

Commits
-------

17ec26e [DI] added support for PHP constants in yaml configuration files
02d1dea [Yaml] added support for parsing PHP constants

Author: fabpot

src/Symfony/Component/DependencyInjection/CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 -----
 
  * allowed to prioritize compiler passes by introducing a third argument to `PassConfig::addPass()`, to `Compiler::addPass` and to `ContainerBuilder::addCompilerPass()`
+ * added support for PHP constants in YAML configuration files
 
 3.0.0
 -----

src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php

@@ -21,6 +21,7 @@
 use Symfony\Component\Config\Resource\FileResource;
 use Symfony\Component\Yaml\Exception\ParseException;
 use Symfony\Component\Yaml\Parser as YamlParser;
+use Symfony\Component\Yaml\Yaml;
 use Symfony\Component\ExpressionLanguage\Expression;
 
 /**
@@ -366,7 +367,7 @@ protected function loadFile($file)
         }
 
         try {
-            $configuration = $this->yamlParser->parse(file_get_contents($file));
+            $configuration = $this->yamlParser->parse(file_get_contents($file), Yaml::PARSE_CONSTANT);
         } catch (ParseException $e) {
             throw new InvalidArgumentException(sprintf('The file "%s" does not contain valid YAML.', $file), 0, $e);
         }

src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/services2.yml

@@ -5,6 +5,7 @@ parameters:
         - false
         - 0
         - 1000.3
+        - !php/const:PHP_INT_MAX
     bar: foo
     escape: '@@escapeme'
     foo_bar: '@foo_bar'

src/Symfony/Component/DependencyInjection/Tests/Loader/YamlFileLoaderTest.php

@@ -97,7 +97,7 @@ public function testLoadParameters()
         $container = new ContainerBuilder();
         $loader = new YamlFileLoader($container, new FileLocator(self::$fixturesPath.'/yaml'));
         $loader->load('services2.yml');
-        $this->assertEquals(array('foo' => 'bar', 'mixedcase' => array('MixedCaseKey' => 'value'), 'values' => array(true, false, 0, 1000.3), 'bar' => 'foo', 'escape' => '@escapeme', 'foo_bar' => new Reference('foo_bar')), $container->getParameterBag()->all(), '->load() converts YAML keys to lowercase');
+        $this->assertEquals(array('foo' => 'bar', 'mixedcase' => array('MixedCaseKey' => 'value'), 'values' => array(true, false, 0, 1000.3, PHP_INT_MAX), 'bar' => 'foo', 'escape' => '@escapeme', 'foo_bar' => new Reference('foo_bar')), $container->getParameterBag()->all(), '->load() converts YAML keys to lowercase');
     }
 
     public function testLoadImports()
@@ -113,7 +113,7 @@ public function testLoadImports()
         $loader->load('services4.yml');
 
         $actual = $container->getParameterBag()->all();
-        $expected = array('foo' => 'bar', 'values' => array(true, false), 'bar' => '%foo%', 'escape' => '@escapeme', 'foo_bar' => new Reference('foo_bar'), 'mixedcase' => array('MixedCaseKey' => 'value'), 'imported_from_ini' => true, 'imported_from_xml' => true);
+        $expected = array('foo' => 'bar', 'values' => array(true, false, PHP_INT_MAX), 'bar' => '%foo%', 'escape' => '@escapeme', 'foo_bar' => new Reference('foo_bar'), 'mixedcase' => array('MixedCaseKey' => 'value'), 'imported_from_ini' => true, 'imported_from_xml' => true);
         $this->assertEquals(array_keys($expected), array_keys($actual), '->load() imports and merges imported files');
 
         // Bad import throws no exception due to ignore_errors value.

src/Symfony/Component/DependencyInjection/composer.json

@@ -19,7 +19,7 @@
         "php": ">=5.5.9"
     },
     "require-dev": {
-        "symfony/yaml": "~2.8|~3.0",
+        "symfony/yaml": "~3.2",
         "symfony/config": "~2.8|~3.0",
         "symfony/expression-language": "~2.8|~3.0"
     },
@@ -29,6 +29,9 @@
         "symfony/expression-language": "For using expressions in service container configuration",
         "symfony/proxy-manager-bridge": "Generate service proxies to lazy load them"
     },
+    "conflict": {
+        "symfony/yaml": "<3.2"
+    },
     "autoload": {
         "psr-4": { "Symfony\\Component\\DependencyInjection\\": "" },
         "exclude-from-classmap": [

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.