diff vendor/symfony/yaml/Inline.php @ 14:1fec387a4317

Update Drupal core to 8.5.2 via Composer

--- a/vendor/symfony/yaml/Inline.php	Mon Apr 23 09:33:26 2018 +0100
+++ b/vendor/symfony/yaml/Inline.php	Mon Apr 23 09:46:53 2018 +0100
@@ -13,6 +13,7 @@
 
 use Symfony\Component\Yaml\Exception\ParseException;
 use Symfony\Component\Yaml\Exception\DumpException;
+use Symfony\Component\Yaml\Tag\TaggedValue;
 
 /**
  * Inline implements a YAML parser/dumper for the YAML inline syntax.
@@ -25,7 +26,8 @@
 {
     const REGEX_QUOTED_STRING = '(?:"([^"\\\\]*+(?:\\\\.[^"\\\\]*+)*+)"|\'([^\']*+(?:\'\'[^\']*+)*+)\')';
 
-    public static $parsedLineNumber;
+    public static $parsedLineNumber = -1;
+    public static $parsedFilename;
 
     private static $exceptionOnInvalidType = false;
     private static $objectSupport = false;
@@ -33,6 +35,24 @@
     private static $constantSupport = false;
 
     /**
+     * @param int         $flags
+     * @param int|null    $parsedLineNumber
+     * @param string|null $parsedFilename
+     */
+    public static function initialize($flags, $parsedLineNumber = null, $parsedFilename = null)
+    {
+        self::$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 & $flags);
+        self::$parsedFilename = $parsedFilename;
+
+        if (null !== $parsedLineNumber) {
+            self::$parsedLineNumber = $parsedLineNumber;
+        }
+    }
+
+    /**
      * Converts a YAML string to a PHP value.
      *
      * @param string $value      A YAML string
@@ -46,7 +66,7 @@
     public static function parse($value, $flags = 0, $references = array())
     {
         if (is_bool($flags)) {
-            @trigger_error('Passing a boolean flag to toggle exception handling is deprecated since version 3.1 and will be removed in 4.0. Use the Yaml::PARSE_EXCEPTION_ON_INVALID_TYPE flag instead.', E_USER_DEPRECATED);
+            @trigger_error('Passing a boolean flag to toggle exception handling is deprecated since Symfony 3.1 and will be removed in 4.0. Use the Yaml::PARSE_EXCEPTION_ON_INVALID_TYPE flag instead.', E_USER_DEPRECATED);
 
             if ($flags) {
                 $flags = Yaml::PARSE_EXCEPTION_ON_INVALID_TYPE;
@@ -56,14 +76,14 @@
         }
 
         if (func_num_args() >= 3 && !is_array($references)) {
-            @trigger_error('Passing a boolean flag to toggle object support is deprecated since version 3.1 and will be removed in 4.0. Use the Yaml::PARSE_OBJECT flag instead.', E_USER_DEPRECATED);
+            @trigger_error('Passing a boolean flag to toggle object support is deprecated since Symfony 3.1 and will be removed in 4.0. Use the Yaml::PARSE_OBJECT flag instead.', E_USER_DEPRECATED);
 
             if ($references) {
                 $flags |= Yaml::PARSE_OBJECT;
             }
 
             if (func_num_args() >= 4) {
-                @trigger_error('Passing a boolean flag to toggle object for map support is deprecated since version 3.1 and will be removed in 4.0. Use the Yaml::PARSE_OBJECT_FOR_MAP flag instead.', E_USER_DEPRECATED);
+                @trigger_error('Passing a boolean flag to toggle object for map support is deprecated since Symfony 3.1 and will be removed in 4.0. Use the Yaml::PARSE_OBJECT_FOR_MAP flag instead.', E_USER_DEPRECATED);
 
                 if (func_get_arg(3)) {
                     $flags |= Yaml::PARSE_OBJECT_FOR_MAP;
@@ -77,10 +97,7 @@
             }
         }
 
-        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 & $flags);
+        self::initialize($flags);
 
         $value = trim($value);
 
@@ -94,7 +111,8 @@
         }
 
         $i = 0;
-        switch ($value[0]) {
+        $tag = self::parseTag($value, $i, $flags);
+        switch ($value[$i]) {
             case '[':
                 $result = self::parseSequence($value, $flags, $i, $references);
                 ++$i;
@@ -104,12 +122,16 @@
                 ++$i;
                 break;
             default:
-                $result = self::parseScalar($value, $flags, null, array('"', "'"), $i, true, $references);
+                $result = self::parseScalar($value, $flags, null, $i, null === $tag, $references);
+        }
+
+        if (null !== $tag) {
+            return new TaggedValue($tag, $result);
         }
 
         // some comments are allowed at the end
         if (preg_replace('/\s+#.*$/A', '', substr($value, $i))) {
-            throw new ParseException(sprintf('Unexpected characters near "%s".', substr($value, $i)));
+            throw new ParseException(sprintf('Unexpected characters near "%s".', substr($value, $i)), self::$parsedLineNumber + 1, $value, self::$parsedFilename);
         }
 
         if (isset($mbEncoding)) {
@@ -132,7 +154,7 @@
     public static function dump($value, $flags = 0)
     {
         if (is_bool($flags)) {
-            @trigger_error('Passing a boolean flag to toggle exception handling is deprecated since version 3.1 and will be removed in 4.0. Use the Yaml::DUMP_EXCEPTION_ON_INVALID_TYPE flag instead.', E_USER_DEPRECATED);
+            @trigger_error('Passing a boolean flag to toggle exception handling is deprecated since Symfony 3.1 and will be removed in 4.0. Use the Yaml::DUMP_EXCEPTION_ON_INVALID_TYPE flag instead.', E_USER_DEPRECATED);
 
             if ($flags) {
                 $flags = Yaml::DUMP_EXCEPTION_ON_INVALID_TYPE;
@@ -142,7 +164,7 @@
         }
 
         if (func_num_args() >= 3) {
-            @trigger_error('Passing a boolean flag to toggle object support is deprecated since version 3.1 and will be removed in 4.0. Use the Yaml::DUMP_OBJECT flag instead.', E_USER_DEPRECATED);
+            @trigger_error('Passing a boolean flag to toggle object support is deprecated since Symfony 3.1 and will be removed in 4.0. Use the Yaml::DUMP_OBJECT flag instead.', E_USER_DEPRECATED);
 
             if (func_get_arg(2)) {
                 $flags |= Yaml::DUMP_OBJECT;
@@ -159,12 +181,16 @@
             case $value instanceof \DateTimeInterface:
                 return $value->format('c');
             case is_object($value):
+                if ($value instanceof TaggedValue) {
+                    return '!'.$value->getTag().' '.self::dump($value->getValue(), $flags);
+                }
+
                 if (Yaml::DUMP_OBJECT & $flags) {
-                    return '!php/object:'.serialize($value);
+                    return '!php/object '.self::dump(serialize($value));
                 }
 
                 if (Yaml::DUMP_OBJECT_AS_MAP & $flags && ($value instanceof \stdClass || $value instanceof \ArrayObject)) {
-                    return self::dumpArray($value, $flags);
+                    return self::dumpArray($value, $flags & ~Yaml::DUMP_EMPTY_ARRAY_AS_SEQUENCE);
                 }
 
                 if (Yaml::DUMP_EXCEPTION_ON_INVALID_TYPE & $flags) {
@@ -256,7 +282,7 @@
     private static function dumpArray($value, $flags)
     {
         // array
-        if ($value && !self::isHash($value)) {
+        if (($value || Yaml::DUMP_EMPTY_ARRAY_AS_SEQUENCE & $flags) && !self::isHash($value)) {
             $output = array();
             foreach ($value as $val) {
                 $output[] = self::dump($val, $flags);
@@ -280,7 +306,6 @@
      * @param string   $scalar
      * @param int      $flags
      * @param string[] $delimiters
-     * @param string[] $stringDelimiters
      * @param int      &$i
      * @param bool     $evaluate
      * @param array    $references
@@ -291,16 +316,16 @@
      *
      * @internal
      */
-    public static function parseScalar($scalar, $flags = 0, $delimiters = null, $stringDelimiters = array('"', "'"), &$i = 0, $evaluate = true, $references = array())
+    public static function parseScalar($scalar, $flags = 0, $delimiters = null, &$i = 0, $evaluate = true, $references = array(), $legacyOmittedKeySupport = false)
     {
-        if (in_array($scalar[$i], $stringDelimiters)) {
+        if (in_array($scalar[$i], array('"', "'"))) {
             // quoted scalar
             $output = self::parseQuotedScalar($scalar, $i);
 
             if (null !== $delimiters) {
                 $tmp = ltrim(substr($scalar, $i), ' ');
                 if (!in_array($tmp[0], $delimiters)) {
-                    throw new ParseException(sprintf('Unexpected characters (%s).', substr($scalar, $i)));
+                    throw new ParseException(sprintf('Unexpected characters (%s).', substr($scalar, $i)), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
                 }
             }
         } else {
@@ -313,20 +338,20 @@
                 if (Parser::preg_match('/[ \t]+#/', $output, $match, PREG_OFFSET_CAPTURE)) {
                     $output = substr($output, 0, $match[0][1]);
                 }
-            } elseif (Parser::preg_match('/^(.+?)('.implode('|', $delimiters).')/', substr($scalar, $i), $match)) {
+            } elseif (Parser::preg_match('/^(.'.($legacyOmittedKeySupport ? '+' : '*').'?)('.implode('|', $delimiters).')/', substr($scalar, $i), $match)) {
                 $output = $match[1];
                 $i += strlen($output);
             } else {
-                throw new ParseException(sprintf('Malformed inline YAML string: %s.', $scalar));
+                throw new ParseException(sprintf('Malformed inline YAML string: %s.', $scalar), self::$parsedLineNumber + 1, null, self::$parsedFilename);
             }
 
             // a non-quoted string cannot start with @ or ` (reserved) nor with a scalar indicator (| or >)
             if ($output && ('@' === $output[0] || '`' === $output[0] || '|' === $output[0] || '>' === $output[0])) {
-                throw new ParseException(sprintf('The reserved indicator "%s" cannot start a plain scalar; you need to quote the scalar.', $output[0]));
+                throw new ParseException(sprintf('The reserved indicator "%s" cannot start a plain scalar; you need to quote the scalar.', $output[0]), self::$parsedLineNumber + 1, $output, self::$parsedFilename);
             }
 
             if ($output && '%' === $output[0]) {
-                @trigger_error(sprintf('Not quoting the scalar "%s" starting with the "%%" indicator character is deprecated since Symfony 3.1 and will throw a ParseException in 4.0.', $output), E_USER_DEPRECATED);
+                @trigger_error(self::getDeprecationMessage(sprintf('Not quoting the scalar "%s" starting with the "%%" indicator character is deprecated since Symfony 3.1 and will throw a ParseException in 4.0.', $output)), E_USER_DEPRECATED);
             }
 
             if ($evaluate) {
@@ -350,7 +375,7 @@
     private static function parseQuotedScalar($scalar, &$i)
     {
         if (!Parser::preg_match('/'.self::REGEX_QUOTED_STRING.'/Au', substr($scalar, $i), $match)) {
-            throw new ParseException(sprintf('Malformed inline YAML string: %s.', substr($scalar, $i)));
+            throw new ParseException(sprintf('Malformed inline YAML string: %s.', substr($scalar, $i)), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
         }
 
         $output = substr($match[0], 1, strlen($match[0]) - 2);
@@ -387,23 +412,28 @@
 
         // [foo, bar, ...]
         while ($i < $len) {
+            if (']' === $sequence[$i]) {
+                return $output;
+            }
+            if (',' === $sequence[$i] || ' ' === $sequence[$i]) {
+                ++$i;
+
+                continue;
+            }
+
+            $tag = self::parseTag($sequence, $i, $flags);
             switch ($sequence[$i]) {
                 case '[':
                     // nested sequence
-                    $output[] = self::parseSequence($sequence, $flags, $i, $references);
+                    $value = self::parseSequence($sequence, $flags, $i, $references);
                     break;
                 case '{':
                     // nested mapping
-                    $output[] = self::parseMapping($sequence, $flags, $i, $references);
-                    break;
-                case ']':
-                    return $output;
-                case ',':
-                case ' ':
+                    $value = self::parseMapping($sequence, $flags, $i, $references);
                     break;
                 default:
                     $isQuoted = in_array($sequence[$i], array('"', "'"));
-                    $value = self::parseScalar($sequence, $flags, array(',', ']'), array('"', "'"), $i, true, $references);
+                    $value = self::parseScalar($sequence, $flags, array(',', ']'), $i, null === $tag, $references);
 
                     // the value can be an array if a reference has been resolved to an array var
                     if (is_string($value) && !$isQuoted && false !== strpos($value, ': ')) {
@@ -416,15 +446,19 @@
                         }
                     }
 
-                    $output[] = $value;
-
                     --$i;
             }
 
+            if (null !== $tag) {
+                $value = new TaggedValue($tag, $value);
+            }
+
+            $output[] = $value;
+
             ++$i;
         }
 
-        throw new ParseException(sprintf('Malformed inline YAML string: %s.', $sequence));
+        throw new ParseException(sprintf('Malformed inline YAML string: %s.', $sequence), self::$parsedLineNumber + 1, null, self::$parsedFilename);
     }
 
     /**
@@ -444,6 +478,7 @@
         $output = array();
         $len = strlen($mapping);
         ++$i;
+        $allowOverwrite = false;
 
         // {foo: bar, bar:foo, ...}
         while ($i < $len) {
@@ -462,20 +497,40 @@
 
             // key
             $isKeyQuoted = in_array($mapping[$i], array('"', "'"), true);
-            $key = self::parseScalar($mapping, $flags, array(':', ' '), array('"', "'"), $i, false);
+            $key = self::parseScalar($mapping, $flags, array(':', ' '), $i, false, array(), true);
 
             if (':' !== $key && false === $i = strpos($mapping, ':', $i)) {
                 break;
             }
 
-            if (':' !== $key && !$isKeyQuoted && (!isset($mapping[$i + 1]) || !in_array($mapping[$i + 1], array(' ', ',', '[', ']', '{', '}'), true))) {
-                @trigger_error('Using a colon after an unquoted mapping key that is not followed by an indication character (i.e. " ", ",", "[", "]", "{", "}") is deprecated since version 3.2 and will throw a ParseException in 4.0.', E_USER_DEPRECATED);
+            if (':' === $key) {
+                @trigger_error(self::getDeprecationMessage('Omitting the key of a mapping is deprecated and will throw a ParseException in 4.0.'), E_USER_DEPRECATED);
             }
 
-            // value
-            $done = false;
+            if (!$isKeyQuoted) {
+                $evaluatedKey = self::evaluateScalar($key, $flags, $references);
+
+                if ('' !== $key && $evaluatedKey !== $key && !is_string($evaluatedKey) && !is_int($evaluatedKey)) {
+                    @trigger_error(self::getDeprecationMessage('Implicit casting of incompatible mapping keys to strings is deprecated since Symfony 3.3 and will throw \Symfony\Component\Yaml\Exception\ParseException in 4.0. Quote your evaluable mapping keys instead.'), E_USER_DEPRECATED);
+                }
+            }
+
+            if (':' !== $key && !$isKeyQuoted && (!isset($mapping[$i + 1]) || !in_array($mapping[$i + 1], array(' ', ',', '[', ']', '{', '}'), true))) {
+                @trigger_error(self::getDeprecationMessage('Using a colon after an unquoted mapping key that is not followed by an indication character (i.e. " ", ",", "[", "]", "{", "}") is deprecated since Symfony 3.2 and will throw a ParseException in 4.0.'), E_USER_DEPRECATED);
+            }
+
+            if ('<<' === $key) {
+                $allowOverwrite = true;
+            }
 
             while ($i < $len) {
+                if (':' === $mapping[$i] || ' ' === $mapping[$i]) {
+                    ++$i;
+
+                    continue;
+                }
+
+                $tag = self::parseTag($mapping, $i, $flags);
                 switch ($mapping[$i]) {
                     case '[':
                         // nested sequence
@@ -483,12 +538,20 @@
                         // Spec: Keys MUST be unique; first one wins.
                         // Parser cannot abort this mapping earlier, since lines
                         // are processed sequentially.
-                        if (!isset($output[$key])) {
-                            $output[$key] = $value;
-                        } else {
-                            @trigger_error(sprintf('Duplicate key "%s" detected on line %d whilst parsing YAML. Silent handling of duplicate mapping keys in YAML is deprecated since version 3.2 and will throw \Symfony\Component\Yaml\Exception\ParseException in 4.0.', $key, self::$parsedLineNumber + 1), E_USER_DEPRECATED);
+                        // But overwriting is allowed when a merge node is used in current block.
+                        if ('<<' === $key) {
+                            foreach ($value as $parsedValue) {
+                                $output += $parsedValue;
+                            }
+                        } elseif ($allowOverwrite || !isset($output[$key])) {
+                            if (null !== $tag) {
+                                $output[$key] = new TaggedValue($tag, $value);
+                            } else {
+                                $output[$key] = $value;
+                            }
+                        } elseif (isset($output[$key])) {
+                            @trigger_error(self::getDeprecationMessage(sprintf('Duplicate key "%s" detected whilst parsing YAML. Silent handling of duplicate mapping keys in YAML is deprecated since Symfony 3.2 and will throw \Symfony\Component\Yaml\Exception\ParseException in 4.0.', $key)), E_USER_DEPRECATED);
                         }
-                        $done = true;
                         break;
                     case '{':
                         // nested mapping
@@ -496,39 +559,45 @@
                         // Spec: Keys MUST be unique; first one wins.
                         // Parser cannot abort this mapping earlier, since lines
                         // are processed sequentially.
-                        if (!isset($output[$key])) {
-                            $output[$key] = $value;
-                        } else {
-                            @trigger_error(sprintf('Duplicate key "%s" detected on line %d whilst parsing YAML. Silent handling of duplicate mapping keys in YAML is deprecated since version 3.2 and will throw \Symfony\Component\Yaml\Exception\ParseException in 4.0.', $key, self::$parsedLineNumber + 1), E_USER_DEPRECATED);
+                        // But overwriting is allowed when a merge node is used in current block.
+                        if ('<<' === $key) {
+                            $output += $value;
+                        } elseif ($allowOverwrite || !isset($output[$key])) {
+                            if (null !== $tag) {
+                                $output[$key] = new TaggedValue($tag, $value);
+                            } else {
+                                $output[$key] = $value;
+                            }
+                        } elseif (isset($output[$key])) {
+                            @trigger_error(self::getDeprecationMessage(sprintf('Duplicate key "%s" detected whilst parsing YAML. Silent handling of duplicate mapping keys in YAML is deprecated since Symfony 3.2 and will throw \Symfony\Component\Yaml\Exception\ParseException in 4.0.', $key)), E_USER_DEPRECATED);
                         }
-                        $done = true;
-                        break;
-                    case ':':
-                    case ' ':
                         break;
                     default:
-                        $value = self::parseScalar($mapping, $flags, array(',', '}'), array('"', "'"), $i, true, $references);
+                        $value = self::parseScalar($mapping, $flags, array(',', '}'), $i, null === $tag, $references);
                         // Spec: Keys MUST be unique; first one wins.
                         // Parser cannot abort this mapping earlier, since lines
                         // are processed sequentially.
-                        if (!isset($output[$key])) {
-                            $output[$key] = $value;
-                        } else {
-                            @trigger_error(sprintf('Duplicate key "%s" detected on line %d whilst parsing YAML. Silent handling of duplicate mapping keys in YAML is deprecated since version 3.2 and will throw \Symfony\Component\Yaml\Exception\ParseException in 4.0.', $key, self::$parsedLineNumber + 1), E_USER_DEPRECATED);
+                        // But overwriting is allowed when a merge node is used in current block.
+                        if ('<<' === $key) {
+                            $output += $value;
+                        } elseif ($allowOverwrite || !isset($output[$key])) {
+                            if (null !== $tag) {
+                                $output[$key] = new TaggedValue($tag, $value);
+                            } else {
+                                $output[$key] = $value;
+                            }
+                        } elseif (isset($output[$key])) {
+                            @trigger_error(self::getDeprecationMessage(sprintf('Duplicate key "%s" detected whilst parsing YAML. Silent handling of duplicate mapping keys in YAML is deprecated since Symfony 3.2 and will throw \Symfony\Component\Yaml\Exception\ParseException in 4.0.', $key)), E_USER_DEPRECATED);
                         }
-                        $done = true;
                         --$i;
                 }
-
                 ++$i;
 
-                if ($done) {
-                    continue 2;
-                }
+                continue 2;
             }
         }
 
-        throw new ParseException(sprintf('Malformed inline YAML string: %s.', $mapping));
+        throw new ParseException(sprintf('Malformed inline YAML string: %s.', $mapping), self::$parsedLineNumber + 1, null, self::$parsedFilename);
     }
 
     /**
@@ -556,11 +625,11 @@
 
             // an unquoted *
             if (false === $value || '' === $value) {
-                throw new ParseException('A reference must contain at least one character.');
+                throw new ParseException('A reference must contain at least one character.', self::$parsedLineNumber + 1, $value, self::$parsedFilename);
             }
 
             if (!array_key_exists($value, $references)) {
-                throw new ParseException(sprintf('Reference "%s" does not exist.', $value));
+                throw new ParseException(sprintf('Reference "%s" does not exist.', $value), self::$parsedLineNumber + 1, $value, self::$parsedFilename);
             }
 
             return $references[$value];
@@ -575,53 +644,97 @@
                 return true;
             case 'false' === $scalarLower:
                 return false;
-            // Optimise for returning strings.
-            case $scalar[0] === '+' || $scalar[0] === '-' || $scalar[0] === '.' || $scalar[0] === '!' || is_numeric($scalar[0]):
+            case '!' === $scalar[0]:
                 switch (true) {
                     case 0 === strpos($scalar, '!str'):
+                        @trigger_error(self::getDeprecationMessage('Support for the !str tag is deprecated since Symfony 3.4. Use the !!str tag instead.'), E_USER_DEPRECATED);
+
                         return (string) substr($scalar, 5);
+                    case 0 === strpos($scalar, '!!str '):
+                        return (string) substr($scalar, 6);
                     case 0 === strpos($scalar, '! '):
+                        @trigger_error(self::getDeprecationMessage('Using the non-specific tag "!" is deprecated since Symfony 3.4 as its behavior will change in 4.0. It will force non-evaluating your values in 4.0. Use plain integers or !!float instead.'), E_USER_DEPRECATED);
+
                         return (int) self::parseScalar(substr($scalar, 2), $flags);
                     case 0 === strpos($scalar, '!php/object:'):
                         if (self::$objectSupport) {
+                            @trigger_error(self::getDeprecationMessage('The !php/object: tag to indicate dumped PHP objects is deprecated since Symfony 3.4 and will be removed in 4.0. Use the !php/object (without the colon) tag instead.'), E_USER_DEPRECATED);
+
                             return unserialize(substr($scalar, 12));
                         }
 
                         if (self::$exceptionOnInvalidType) {
-                            throw new ParseException('Object support when parsing a YAML file has been disabled.');
+                            throw new ParseException('Object support when parsing a YAML file has been disabled.', self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
                         }
 
                         return;
                     case 0 === strpos($scalar, '!!php/object:'):
                         if (self::$objectSupport) {
-                            @trigger_error('The !!php/object tag to indicate dumped PHP objects is deprecated since version 3.1 and will be removed in 4.0. Use the !php/object tag instead.', E_USER_DEPRECATED);
+                            @trigger_error(self::getDeprecationMessage('The !!php/object: tag to indicate dumped PHP objects is deprecated since Symfony 3.1 and will be removed in 4.0. Use the !php/object (without the colon) tag instead.'), E_USER_DEPRECATED);
 
                             return unserialize(substr($scalar, 13));
                         }
 
                         if (self::$exceptionOnInvalidType) {
-                            throw new ParseException('Object support when parsing a YAML file has been disabled.');
+                            throw new ParseException('Object support when parsing a YAML file has been disabled.', self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
+                        }
+
+                        return;
+                    case 0 === strpos($scalar, '!php/object'):
+                        if (self::$objectSupport) {
+                            return unserialize(self::parseScalar(substr($scalar, 12)));
+                        }
+
+                        if (self::$exceptionOnInvalidType) {
+                            throw new ParseException('Object support when parsing a YAML file has been disabled.', self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
                         }
 
                         return;
                     case 0 === strpos($scalar, '!php/const:'):
                         if (self::$constantSupport) {
+                            @trigger_error(self::getDeprecationMessage('The !php/const: tag to indicate dumped PHP constants is deprecated since Symfony 3.4 and will be removed in 4.0. Use the !php/const (without the colon) tag instead.'), E_USER_DEPRECATED);
+
                             if (defined($const = substr($scalar, 11))) {
                                 return constant($const);
                             }
 
-                            throw new ParseException(sprintf('The constant "%s" is not defined.', $const));
+                            throw new ParseException(sprintf('The constant "%s" is not defined.', $const), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
                         }
                         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));
+                            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?', $scalar), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
+                        }
+
+                        return;
+                    case 0 === strpos($scalar, '!php/const'):
+                        if (self::$constantSupport) {
+                            $i = 0;
+                            if (defined($const = self::parseScalar(substr($scalar, 11), 0, null, $i, false))) {
+                                return constant($const);
+                            }
+
+                            throw new ParseException(sprintf('The constant "%s" is not defined.', $const), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
+                        }
+                        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?', $scalar), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
                         }
 
                         return;
                     case 0 === strpos($scalar, '!!float '):
                         return (float) substr($scalar, 8);
+                    case 0 === strpos($scalar, '!!binary '):
+                        return self::evaluateBinaryScalar(substr($scalar, 9));
+                    default:
+                        @trigger_error(self::getDeprecationMessage(sprintf('Using the unquoted scalar value "%s" is deprecated since Symfony 3.3 and will be considered as a tagged value in 4.0. You must quote it.', $scalar)), E_USER_DEPRECATED);
+                }
+
+            // Optimize for returning strings.
+            // no break
+            case '+' === $scalar[0] || '-' === $scalar[0] || '.' === $scalar[0] || is_numeric($scalar[0]):
+                switch (true) {
                     case Parser::preg_match('{^[+-]?[0-9][0-9_]*$}', $scalar):
                         $scalar = str_replace('_', '', (string) $scalar);
                         // omitting the break / return as integers are handled in the next case
+                        // no break
                     case ctype_digit($scalar):
                         $raw = $scalar;
                         $cast = (int) $scalar;
@@ -642,12 +755,10 @@
                         return -log(0);
                     case '-.inf' === $scalarLower:
                         return log(0);
-                    case 0 === strpos($scalar, '!!binary '):
-                        return self::evaluateBinaryScalar(substr($scalar, 9));
                     case Parser::preg_match('/^(-|\+)?[0-9][0-9,]*(\.[0-9_]+)?$/', $scalar):
                     case Parser::preg_match('/^(-|\+)?[0-9][0-9_]*(\.[0-9_]+)?$/', $scalar):
                         if (false !== strpos($scalar, ',')) {
-                            @trigger_error('Using the comma as a group separator for floats is deprecated since version 3.2 and will be removed in 4.0.', E_USER_DEPRECATED);
+                            @trigger_error(self::getDeprecationMessage('Using the comma as a group separator for floats is deprecated since Symfony 3.2 and will be removed in 4.0.'), E_USER_DEPRECATED);
                         }
 
                         return (float) str_replace(array(',', '_'), '', $scalar);
@@ -664,9 +775,48 @@
 
                         return $time;
                 }
-            default:
-                return (string) $scalar;
         }
+
+        return (string) $scalar;
+    }
+
+    /**
+     * @param string $value
+     * @param int    &$i
+     * @param int    $flags
+     *
+     * @return null|string
+     */
+    private static function parseTag($value, &$i, $flags)
+    {
+        if ('!' !== $value[$i]) {
+            return;
+        }
+
+        $tagLength = strcspn($value, " \t\n", $i + 1);
+        $tag = substr($value, $i + 1, $tagLength);
+
+        $nextOffset = $i + $tagLength + 1;
+        $nextOffset += strspn($value, ' ', $nextOffset);
+
+        // Is followed by a scalar
+        if ((!isset($value[$nextOffset]) || !in_array($value[$nextOffset], array('[', '{'), true)) && 'tagged' !== $tag) {
+            // Manage non-whitelisted scalars in {@link self::evaluateScalar()}
+            return;
+        }
+
+        // Built-in tags
+        if ($tag && '!' === $tag[0]) {
+            throw new ParseException(sprintf('The built-in tag "!%s" is not implemented.', $tag), self::$parsedLineNumber + 1, $value, self::$parsedFilename);
+        }
+
+        if (Yaml::PARSE_CUSTOM_TAGS & $flags) {
+            $i = $nextOffset;
+
+            return $tag;
+        }
+
+        throw new ParseException(sprintf('Tags support is not enabled. Enable the `Yaml::PARSE_CUSTOM_TAGS` flag to use "!%s".', $tag), self::$parsedLineNumber + 1, $value, self::$parsedFilename);
     }
 
     /**
@@ -681,11 +831,11 @@
         $parsedBinaryData = self::parseScalar(preg_replace('/\s/', '', $scalar));
 
         if (0 !== (strlen($parsedBinaryData) % 4)) {
-            throw new ParseException(sprintf('The normalized base64 encoded data (data without whitespace characters) length must be a multiple of four (%d bytes given).', strlen($parsedBinaryData)));
+            throw new ParseException(sprintf('The normalized base64 encoded data (data without whitespace characters) length must be a multiple of four (%d bytes given).', strlen($parsedBinaryData)), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
         }
 
         if (!Parser::preg_match('#^[A-Z0-9+/]+={0,2}$#i', $parsedBinaryData)) {
-            throw new ParseException(sprintf('The base64 encoded data (%s) contains invalid characters.', $parsedBinaryData));
+            throw new ParseException(sprintf('The base64 encoded data (%s) contains invalid characters.', $parsedBinaryData), self::$parsedLineNumber + 1, $scalar, self::$parsedFilename);
         }
 
         return base64_decode($parsedBinaryData, true);
@@ -730,4 +880,19 @@
     {
         return '~^0x[0-9a-f_]++$~i';
     }
+
+    private static function getDeprecationMessage($message)
+    {
+        $message = rtrim($message, '.');
+
+        if (null !== self::$parsedFilename) {
+            $message .= ' in '.self::$parsedFilename;
+        }
+
+        if (-1 !== self::$parsedLineNumber) {
+            $message .= ' on line '.(self::$parsedLineNumber + 1);
+        }
+
+        return $message.'.';
+    }
 }