Dear OCaml users,
<= /div>

The release of OCaml version = 5.2.1 is imminent.
OCaml 5.2.1 is a collection of safe but import runtim= e time bug fixes backported from

the 5.3 branch of OCaml. The ful= l list of bug fixes is available below.

In order to ensure that the = future release works as expected, we are planning to test

a relea= se candidate during the upcoming week.

If you find any bugs, please = report them here on GitHub at

https://github.com/ocaml/ocaml/issues .

Happy ha= cking,

Florian Angeletti

<= br data-mce-bogus=3D"1">

Installation Instructions

-------------------------------

The base compiler can be inst= alled as an opam switch with the following commands on opam 2.1:

&nb= sp;   opam update
    opam switch create 5.2.1~= rc1

The source code for the release candidate is available on
- GitHub: https://github.com/ocaml/ocaml/archive/5.2.1-rc1.tar.gz
- Inr= ia archives: https://caml.inria.fr/pub/distrib/ocaml-5.2/ocaml-5.2.1~rc1.ta= r.gz

Fine-Tuned Compiler Configuration
--------------------------= --------------------

If you want to tweak the configuration of the c= ompiler, you can switch to the option variant with:

  &nbs= p; opam update
     opam switch create <swi= tch_name> ocaml-variants.5.2.1~rc1+options <option_list>

wh= ere `<option_list>` is a space-separated list of `ocaml-option-*` pac= kages. For instance, for a `flambda` and `no-flat-float-array` switch:
<= br>     opam switch create 5.2.1~rc1+flambda+nffa ocaml= -variants.5.2.1~rc1+options ocaml-option-flambda ocaml-option-no-flat-float= -array

All available options can be listed with `opam search ocaml-o= ption`.

----------------------------------

Changes Since OCam= l 5.2.0

- #13207(https://github.com/ocaml/ocaml/issues/13207): Be sure= to reload the register caching the exception handler in
  &nb= sp; caml_c_call and caml_c_call_stack_args, as its value may have been chan= ged
    if the OCaml stack is expanded during a callback.=
    (Miod Vallat, report by Vesa Karvonen, review by Gab= riel Scherer and
     Xavier Leroy)

&n= bsp; - #13252(https://github.com/ocaml/ocaml/issues/13252): Rework register= assignment in the interpreter code on m68k on Linux,
   = due to the %a5 register being used by Glibc.
    (Miod V= allat, report by St=E9phane Glondu, review by Gabriel Scherer and
=     Xavier Leroy)

- #13268(https://gith= ub.com/ocaml/ocaml/issues/13268): Fix a call to test in configure.ac that w= as causing errors when
    LDFLAGS contains several words= .
    (St=E9phane Glondu, review by Miod Vallat)
= ;
- #13234(https://github.com/ocaml/ocaml/issues/13234), [#13267= ](https://github.com/ocaml/ocaml/issues/13267): Open runtime events file in= read-write mode on armel
    (armv5) systems due to atom= ic operations limitations on that
    platform.
=    (St=E9phane Glondu, review by Miod Vallat and Vincent Laviron)=

- #13188(https://github.com/ocaml/ocaml/issues/13188)= : fix races in the FFI code coming from the use of Int_val(...)
&n= bsp; on rooted values inside blocking questions / without the runtime= lock.
    (Calling Int_val(...) on non-rooted immediates= is fine, but any
     access to rooted values must = be done outside blocking sections /
     with the ru= ntime lock.)
    (Etienne Millon, review by Gabriel Scher= er, Jan Midtgaard, Olivier Nicole)

- #13318(https://gi= thub.com/ocaml/ocaml/issues/13318): Fix regression in GC alarms, and fix th= em for flambda.
    (Guillaume Munch-Maccagnoni, report b= y Benjamin Monate, review by
     Vincent Laviron an= d Gabriel Scherer)

- #13140(https://github.com/ocaml/o= caml/issues/13140): POWER back-end: fix issue with call to `caml_call_reall= oc_stack`
    from a DLL
    (Xavier Le= roy, review by Miod Vallat)

- #13370(https://github.co= m/ocaml/ocaml/issues/13370): Fix a low-probability crash when calling Gc.co= unters.
    (Demi Marie Obenour, review by Gabriel Schere= r)

- #13402(https://github.com/ocaml/ocaml/issues/1340= 2), #13512(https://github.com/ocaml/ocaml/issues/13512), #13549(https://git= hub.com/ocaml/ocaml/issues/13549), #13553(https://github.com/ocaml/ocaml/is= sues/13553): Revise bytecode implementation of callbacks
  &nb= sp; so that it no longer produces dangling registered bytecode fragments.    (Xavier Leroy, report by Jan Midtgaard, analysis by St= ephen Dolan,
     review by Miod Vallat)
<= br> - #13502(https://github.com/ocaml/ocaml/issues/13502): Fix misind= exing related to `Gc.finalise_last` that could prevent
   = ; finalisers from being run.
    (Nick Roberts, review by= Mark Shinwell)

- #13520(https://github.com/ocaml/ocam= l/issues/13520): Fix compilation of native-code version of systhreads. Byte= code fields
    were being included in the thread descrip= tors.
    (David Allsopp, review by S=E9bastien Hinderer = and Miod Vallat)

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