Fable 5.0.0-alpha.14 released!

NewsBot · 25 July 2025 21:19

Fable 5.0.0-alpha.14 has been released.

Added

[Python] Support for Nullable Reference Types (by @dbrattli)

[JS/TS] Fix #3533: Add directives prologues supports (by @MangelMaxime)

[JS/TS] Support for Nullable Reference Types (by @ncave and @MangelMaxime)

[Rust] Initial support for Nullable Reference Types (by @ncave)

Changed

[Python] Use Python 3.12 type parameter syntax. Deprecate Python 3.10 and 3.11 (by @dbrattli)

[Python] Records now snake-cases all member fields (by @dbrattli)

[Python] Anonymous records now preserves the casing of member fields (by @dbrattli)

[Python] Option type is now Option[T] instead of T | None (by @dbrattli)

[Python] Use uv instead of Poetry for package management (by @dbrattli)

[Python] Fable Library for Python is now partially written in Rust (by @dbrattli)

[All] Improve filewatcher error messages (by @goswinr)

Fixed

[Python] Fixed static properties and are now translated as Python class attributes (by @dbrattli)

[Python] Fixed DateTime with DateTimeKind generates proper enum reference (#3689) (by @dbrattli)

[Python] Fixed Dictionary KeyValuePair enumeration when casting to IEnumerable (#3771) (by @dbrattli)

[Python] Fixed createEmpty<T> for interfaces using SimpleNamespace with type casting (#3604) (by @dbrattli)

[Python] Fixed EmitMethod + ParamObject losing keyword arguments (#3871) (by @dbrattli)

[Python] Fixed EmitConstructor + ParamObject losing keyword arguments (#3871) (by @dbrattli)

[Python] Fixed DateTimeOffset.TryParse, ToString() and Offset property access (#3854) (by @dbrattli)

[Python] Fixed anonymous records in Maps causing comparison errors (#3869) (by @dbrattli)

[Python] Fixed handling of erased types for Python (#3968) (by @dbrattli)

[Python] Fixed unit function (zero arguments functions) are transpiled inconsistently (#4126) (by @dbrattli)

[Python] Fixed resource managers with empty body (#3912) (by @dbrattli)

[Python] Fixed Async.Sleepto handle TimeSpan…

Link: Release 5.0.0-alpha.14 · fable-compiler/Fable · GitHub