HHVM 4.29 is released! This release marks the end of support for 4.23; 4.24–4.28 remain supported, as do the LTS releases 3.30 and 4.8.

Highlights

Error messages now strip HH\ from names that are automatically imported into every namespace
Fixed .hack files not being correctly indexed by some IDE features
Shape key autocomplete now detects pre-existing quotes, avoiding completions such as $someshape['somekey''] with two apostrophes; this was most common with IDEs configured to automatically insert matching quotation marks.
Added RuntimeOption::CheckIntOverflow option:
- if 0 (the default), overflows will silently wrap; this setting has the best performance
- if 1, overflows will wrap and warn
- if 2, overflows will throw an exception
Autocomplete now downranks magic methods and functions/methods with DO_NOT_USE in the name

Breaking Changes

$c->toVector(), $c->toSet(), $c->toMap() have been removed from Hack collections; use new Vector($c) etc or Hack Arrays instead; this is because they are not type-safe, as variance checks were added for generics
auto-imported reserved names (e.g. ‘self’) are now case-sensitive at runtime
Set::zip() now returns Set<nothing>, as pairs can not be stored in Sets; this could lead to new type errors in code that would previously fail at runtime. Similar changes have been made to ImmSet and other related classes
unserialize() no longer creates references; if old serialized data containing references is used, the referenced value will be copied instead
references are no longer supported by the parser
the runtime and typechecker now agree that Awaitable’s fully-qualified name is HH\Awaitable; it remains autoimported. In previous releases, the runtime considered it to be HH\Awaitable, but the typechecker considered it to be \Awaitable
it is now an error to pass a superglobal as inout
array (without generics) is now considered to be the union of array<_> (a.k.a varray) and array<_, _> (a.k.a. darray); this can lead to stricter handling of key (example 1, example 2)