Chris@13: Upgrading from PHP-Parser 3.x to 4.0
Chris@13: ====================================
Chris@13: 
Chris@13: ### PHP version requirements
Chris@13: 
Chris@13: PHP-Parser now requires PHP 7.0 or newer to run. It is however still possible to *parse* PHP 5.2-5.6
Chris@13: source code, while running on a newer version.
Chris@13: 
Chris@13: HHVM is no longer actively supported.
Chris@13: 
Chris@13: ### Changes to the node structure
Chris@13: 
Chris@13: * Many subnodes that previously held simple strings now store `Identifier` nodes instead (or
Chris@13:   `VarLikeIdentifier` nodes if they have form `$ident`). The constructors of the affected nodes will
Chris@13:   automatically convert strings to `Identifier`s and `Identifier`s implement `__toString()`. As such
Chris@13:   some code continues to work without changes, but anything using `is_string()`, type-strict
Chris@13:   comparisons or strict-mode may require adjustment. The following is an exhaustive list of all
Chris@13:   affected subnodes:
Chris@13: 
Chris@16:    * `Const_::$name`
Chris@13:    * `NullableType::$type` (for simple types)
Chris@13:    * `Param::$type` (for simple types)
Chris@13:    * `Expr\ClassConstFetch::$name`
Chris@13:    * `Expr\Closure::$returnType` (for simple types)
Chris@13:    * `Expr\MethodCall::$name`
Chris@13:    * `Expr\PropertyFetch::$name`
Chris@13:    * `Expr\StaticCall::$name`
Chris@13:    * `Expr\StaticPropertyFetch::$name` (uses `VarLikeIdentifier`)
Chris@13:    * `Stmt\Class_::$name`
Chris@13:    * `Stmt\ClassMethod::$name`
Chris@13:    * `Stmt\ClassMethod::$returnType` (for simple types)
Chris@16:    * `Stmt\Function_::$name`
Chris@16:    * `Stmt\Function_::$returnType` (for simple types)
Chris@13:    * `Stmt\Goto_::$name`
Chris@13:    * `Stmt\Interface_::$name`
Chris@13:    * `Stmt\Label::$name`
Chris@13:    * `Stmt\PropertyProperty::$name` (uses `VarLikeIdentifier`)
Chris@13:    * `Stmt\TraitUseAdaptation\Alias::$method`
Chris@13:    * `Stmt\TraitUseAdaptation\Alias::$newName`
Chris@13:    * `Stmt\TraitUseAdaptation\Precedence::$method`
Chris@13:    * `Stmt\Trait_::$name`
Chris@13:    * `Stmt\UseUse::$alias`
Chris@13: 
Chris@13: * Expression statements (`expr;`) are now represented using a `Stmt\Expression` node. Previously
Chris@13:   these statements were directly represented as their constituent expression.
Chris@13: * The `name` subnode of `Param` has been renamed to `var` and now contains a `Variable` rather than
Chris@13:   a plain string.
Chris@13: * The `name` subnode of `StaticVar` has been renamed to `var` and now contains a `Variable` rather
Chris@13:   than a plain string.
Chris@13: * The `var` subnode of `ClosureUse` now contains a `Variable` rather than a plain string.
Chris@16: * The `var` subnode of `Catch_` now contains a `Variable` rather than a plain string.
Chris@13: * The `alias` subnode of `UseUse` is now `null` if no explicit alias is given. As such,
Chris@13:   `use Foo\Bar` and `use Foo\Bar as Bar` are now represented differently. The `getAlias()` method
Chris@13:   can be used to get the effective alias, even if it is not explicitly given.
Chris@13: 
Chris@13: ### Miscellaneous
Chris@13: 
Chris@13: * The indentation handling in the pretty printer has been changed (this is only relevant if you
Chris@13:   extend the pretty printer). Previously indentation was automatic, and parts were excluded using
Chris@13:   `pNoindent()`. Now no-indent is the default and newlines that require indentation should use
Chris@13:   `$this->nl`.
Chris@13: 
Chris@13: ### Removed functionality
Chris@13: 
Chris@16: * Removed `type` subnode on `Class_`, `ClassMethod` and `Property` nodes. Use `flags` instead.
Chris@13: * The `ClassConst::isStatic()` method has been removed. Constants cannot have a static modifier.
Chris@13: * The `NodeTraverser` no longer accepts `false` as a return value from a `leaveNode()` method.
Chris@13:   `NodeTraverser::REMOVE_NODE` should be returned instead.
Chris@13: * The `Node::setLine()` method has been removed. If you really need to, you can use `setAttribute()`
Chris@13:   instead.
Chris@13: * The misspelled `Class_::VISIBILITY_MODIFER_MASK` constant has been dropped in favor of
Chris@13:   `Class_::VISIBILITY_MODIFIER_MASK`.
Chris@13: * The XML serializer has been removed. As such, the classes `Serializer\XML`, and
Chris@13:   `Unserializer\XML`, as well as the interfaces `Serializer` and `Unserializer` no longer exist.
Chris@13: * The `BuilderAbstract` class has been removed. It's functionality is moved into `BuilderHelpers`.
Chris@13:   However, this is an internal class and should not be used directly.
Chris@16: * The `Autoloader` class has been removed in favor of relying on the Composer autoloader.