CHANGELOG

4.2.0

The behavior of the non-specific tag ! is changed and now forces non-evaluating your values.
complex mappings will throw a ParseException
support for the comma as a group separator for floats has been dropped, use the underscore instead
support for the !!php/object tag has been dropped, use the !php/object tag instead
duplicate mapping keys throw a ParseException
non-string mapping keys throw a ParseException, use the Yaml::PARSE_KEYS_AS_STRINGS flag to cast them to strings
% at the beginning of an unquoted string throw a ParseException
mappings with a colon (:) that is not followed by a whitespace throw a ParseException
the Dumper::setIndentation() method has been removed
being able to pass boolean options to the Yaml::parse(), Yaml::dump(), Parser::parse(), and Dumper::dump() methods to configure the behavior of the parser and dumper is no longer supported, pass bitmask flags instead
the constructor arguments of the Parser class have been removed
the Inline class is internal and no longer part of the BC promise
removed support for the !str tag, use the !!str tag instead

added support for tagged scalars.

Yaml::parse('!foo bar', Yaml::PARSE_CUSTOM_TAGS);
// returns TaggedValue('foo', 'bar');

added support for parsing YAML files using the Yaml::parseFile() or Parser::parseFile() method
the Dumper, Parser, and Yaml classes are marked as final
Deprecated the !php/object: tag which will be replaced by the !php/object tag (without the colon) in 4.0.
Deprecated the !php/const: tag which will be replaced by the !php/const tag (without the colon) in 4.0.
Support for the !str tag is deprecated, use the !!str tag instead.
Deprecated using the non-specific tag ! as its behavior will change in 4.0. It will force non-evaluating your values in 4.0. Use plain integers or !!float instead.

Starting an unquoted string with a question mark followed by a space is deprecated and will throw a ParseException in Symfony 4.0.
Deprecated support for implicitly parsing non-string mapping keys as strings. Mapping keys that are no strings will lead to a ParseException in Symfony 4.0. Use quotes to opt-in for keys to be parsed as strings.

Before:
```
$yaml = <<<YAML
null: null key
true: boolean true
2.0: float key
YAML;

Yaml::parse($yaml);
```
After:
```
$yaml = <<<YAML
"null": null key
"true": boolean true
"2.0": float key
YAML;

Yaml::parse($yaml);
```
Omitted mapping values will be parsed as null.
Omitting the key of a mapping is deprecated and will throw a ParseException in Symfony 4.0.

Added support for dumping empty PHP arrays as YAML sequences:

Yaml::dump([], 0, 0, Yaml::DUMP_EMPTY_ARRAY_AS_SEQUENCE);

Mappings with a colon (:) that is not followed by a whitespace are deprecated when the mapping key is not quoted and will lead to a ParseException in Symfony 4.0 (e.g. foo:bar must be foo: bar).

Added support for parsing PHP constants:

Yaml::parse('!php/const:PHP_INT_MAX', Yaml::PARSE_CONSTANT);

Support for silently ignoring duplicate mapping keys in YAML has been deprecated and will lead to a ParseException in Symfony 4.0.

Added support to dump stdClass and ArrayAccess objects as YAML mappings through the Yaml::DUMP_OBJECT_AS_MAP flag.
Strings that are not UTF-8 encoded will be dumped as base64 encoded binary data.
Added support for dumping multi line strings as literal blocks.
Added support for parsing base64 encoded binary data when they are tagged with the !!binary tag.

Added support for parsing timestamps as \DateTime objects:

Yaml::parse('2001-12-15 21:59:43.10 -5', Yaml::PARSE_DATETIME);

Added support for customizing the YAML parser behavior through an optional bit field:

Yaml::parse('{ "foo": "bar", "fiz": "cat" }', Yaml::PARSE_EXCEPTION_ON_INVALID_TYPE | Yaml::PARSE_OBJECT | Yaml::PARSE_OBJECT_FOR_MAP);

Added support for customizing the dumped YAML string through an optional bit field:

Yaml::dump(array('foo' => new A(), 'bar' => 1), 0, 0, Yaml::DUMP_EXCEPTION_ON_INVALID_TYPE | Yaml::DUMP_OBJECT);

Yaml::parse() now throws an exception when a blackslash is not escaped in double-quoted strings

Yaml::parse() does not evaluate loaded files as PHP files by default anymore (call Yaml::enablePhpParsing() to get back the old behavior)