Dear OCaml users,
One month and half after the release of the first alpha for OCaml 5.3.0, the
release of OCaml 5.3.0 is drawing near.
The internal API of the compiler libraries has been frozen, and most core
developer tools support (or will support soon) the new version of the compiler.
We have thus released a first beta version of OCaml 5.3.0 to help you update
your software and libraries ahead of the release (see below for the installation
instructions). More information about the whole release process is now available
in the compiler repository
(https://github.com/ocaml/ocaml/blob/trunk/release-info/introduction.md).
Compared to the first alpha release, this beta contains a few runtime or
typechecker fixes, a handful of fixes for the runtime event library and other
miscellaneous fixes.
Exceptionally, this beta release also introduces a new flag `-keywords` for the
compiler. This backward compatibility flag aims to help compiling old code that
are using `effect` as a normal identifier, now that `effect` is a keyword in the
new effect handler syntax.
The progresses on stabilising the ecosystem are tracked on the
opam readiness for 5.3.0 meta-issue
(https://github.com/ocaml/opam-repository/issues/26596).
The full release is expected in the end of November or beginning of December,
see the new prospective calendar
(https://github.com/ocaml/ocaml/blob/trunk/release-info/calendar.md) for more
information.
If you find any bugs, please report them on OCaml's issue tracker
(https://github.com/ocaml/ocaml/issues).
If you are interested in full list of features and bug fixes of the new OCaml
version, the updated change log for OCaml 5.3.0 is available on GitHub
(https://github.com/ocaml/ocaml/blob/5.3/Changes),
and a short list of the changes since the last alpha is available below.
Happy hacking,
Florian Angeletti for the OCaml team.
---
## Installation Instructions
The base compiler can be installed as an opam switch with the following commands
on opam 2.1 and later:
```bash
opam update
opam switch create 5.3.0~beta1
```
The source code for the beta is also available at these addresses:
* [GitHub](https://github.com/ocaml/ocaml/archive/5.3.0-beta1.tar.gz)
* [OCaml archives at Inria](https://caml.inria.fr/pub/distrib/ocaml-5.3/ocaml-5.3.0~beta1.tar.gz)
### Fine-Tuned Compiler Configuration
If you want to tweak the configuration of the compiler, you can switch to the option variant with:
```bash
opam update
opam switch create <switch_name> ocaml-variants.5.3.0~beta1+options <option_list>
```
where `option_list` is a space separated list of `ocaml-option-*` packages. For instance, for a flambda and no-flat-float-array switch:
```bash
opam switch create 5.3.0~beta1+flambda+nffa ocaml-variants.5.3.0~beta1+options ocaml-option-flambda ocaml-option-no-flat-float-array
```
All available options can be listed with `opam search ocaml-option`.
-------
## Changes since the first alpha
### Runtime fixes
- #13502(https://github.com/ocaml/ocaml/issues/13502): Fix misindexing related to `Gc.finalise_last` that could prevent
finalisers from being run.
(Nick Roberts, review by Mark Shinwell)
- #13402(https://github.com/ocaml/ocaml/issues/13402), #13512(https://github.com/ocaml/ocaml/issues/13512), #13549(https://github.com/ocaml/ocaml/issues/13549), #13553(https://github.com/ocaml/ocaml/issues/13553): Revise bytecode implementation of callbacks
so that it no longer produces dangling registered bytecode fragments.
(Xavier Leroy, report by Jan Midtgaard, analysis by Stephen Dolan,
review by Miod Vallat)
- #13520(https://github.com/ocaml/ocaml/issues/13520): Fix compilation of native-code version of systhreads. Bytecode fields
were being included in the thread descriptors.
(David Allsopp, review by Sébastien Hinderer and Miod Vallat)
### Typechecker fixes
- #13579(https://github.com/ocaml/ocaml/issues/13579), [#13583](https://github.com/ocaml/ocaml/issues/13583): Unsoundness involving non-injective types + gadts
(Jacques Garrigue, report by @v-gb,
review by Richard Eisenberg and Florian Angeletti)
- #13388(https://github.com/ocaml/ocaml/issues/13388), [#13540](https://github.com/ocaml/ocaml/issues/13540): raises an error message (and not an internal compiler error)
when two local substitutions are incompatible (for instance `module type
S:=sig end type t:=(module S)`)
(Florian Angeletti, report by Nailen Matschke, review by Gabriel Scherer, and
Leo White)
### Compiler flag
- #13471(https://github.com/ocaml/ocaml/issues/13471): add `-keywords <version?+list>` flag to define the list of keywords
recognized by the lexer, for instance `-keywords 5.2` disable the `effect`
keyword.
(Florian Angeletti, review by Gabriel Scherer)
### Runtime event library fixes
- #13419(https://github.com/ocaml/ocaml/issues/13419): Fix memory bugs in runtime events system.
(B. Szilvasy and Nick Barnes, review by Miod Vallat, Nick Barnes,
Tim McGilchrist, and Gabriel Scherer)
- #13407(https://github.com/ocaml/ocaml/issues/13407): Add Runtime_events.EV_EMPTY_MINOR
(Thomas Leonard)
- #13522(https://github.com/ocaml/ocaml/issues/13522): Confirm runtime events ring is still active after callback.
(KC Sivaramakrishnan, review by Sadiq Jaffer and Miod Vallat)
- #13529(https://github.com/ocaml/ocaml/issues/13529): Do not write to event ring after going out of stw participant set.
(KC Sivaramakrishnan, review by Sadiq Jaffer)
### Documentation
- #13424(https://github.com/ocaml/ocaml/issues/13424): Fix `Gc.quick_stat` documentation to clarify that returned fields
`live_words`, `live_blocks`, `free_words`, and `fragments` are not zero.
(Jan Midtgaard, review by Damien Doligez and KC Sivaramakrishnan)
- #13440(https://github.com/ocaml/ocaml/issues/13440): Update documentation of `Gc.{control,get,set}` to reflect fields
not currently supported on OCaml 5.
(Jan Midtgaard, review by Gabriel Scherer)
- #13469(https://github.com/ocaml/ocaml/issues/13469), #13474(https://github.com/ocaml/ocaml/issues/13474), #13535(https://github.com/ocaml/ocaml/issues/13535): Document that [Hashtbl.create n] creates a hash table
with a default minimal size, even if [n] is very small or negative.
(Antonin Décimo, Nick Bares, report by Nikolaus Huber and Jan Midtgaard,
review by Florian Angeletti, Anil Madhavapeddy, Gabriel Scherer,
and Miod Vallat)
### Standard library internal fix
- #13543(https://github.com/ocaml/ocaml/issues/13543): Remove some String-Bytes conversion from the stdlib to behave better
with js_of_ocaml
(Hugo Heuzard, review by Gabriel Scherer)
### Toplevel fix
- #13263(https://github.com/ocaml/ocaml/issues/13263), #13560(https://github.com/ocaml/ocaml/issues/13560): fix printing true and false in toplevel and error
messages (no more unexpected \#true)
(Florian Angeletti, report by Samuel Vivien, review by Gabriel Scherer)
### Compiler internals
- #13391(https://github.com/ocaml/ocaml/issues/13391), [#13551](https://github.com/ocaml/ocaml/issues/13551): fix a printing bug with `-dsource` when using
raw literal inside a locally abstract type constraint
(i.e. `let f: type \#for. ... `)
(Florian Angeletti, report by Nick Roberts, review by Richard Eisenberg)