Hello.

When I try to build this package on a VM with 1 CPU, the build never
ends and sbuild has to kill the dpkg-buildpackage process (see below).

Full build log available here:

https://people.debian.org/~sanvila/build-logs/202609/

Apparently this happens because of this line in kcas_integration:

num_domains = Domain.recommended_domain_count () - 2.

which yields 1 - 2 = -1, a negative value. The consequences of this
are explained in the forwarded URL above.

The attached trivial patch, which I also forwarded upstream, should fix it.

The build error may be reproduced easily with GRUB_CMDLINE_LINUX="nr_cpus=1",
but if that does not work, I can offer a VM for you to reproduce.

Thanks.
--------------------------------------------------------------------------------
[...]
Called from Dune__exe__Backtrace.main in file "test/backtrace.ml", lines 21-24, characters 2-46
Called from Dune__exe__Backtrace in file "test/backtrace.ml", line 29, characters 6-13
(cd _build/default/test && ./test_chan.exe)
Sender on domain 1 done
Receiver on domain 2 done
(cd _build/default/test && ./fib.exe)
fib(43) = 701408733
(cd _build/default/test && ./fib_par.exe)
fib(43) = 701408733
E: Build killed with signal TERM after 60 minutes of inactivity
--------------------------------------------------------------------------------

We believe that the bug you reported is fixed in the latest version of
ocaml-domainslib, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1149269@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Stéphane Glondu <glondu@debian.org> (supplier of updated ocaml-domainslib package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Tue, 29 Sep 2026 09:18:28 +0200
Source: ocaml-domainslib
Architecture: source
Version: 0.5.2-3
Distribution: unstable
Urgency: medium
Maintainer: Debian OCaml Maintainers <debian-ocaml-maint@lists.debian.org>
Changed-By: Stéphane Glondu <glondu@debian.org>
Closes: 1149269
Changes:
 ocaml-domainslib (0.5.2-3) unstable; urgency=medium
 .
   * Fix hang on single CPU systems (Closes: #1149269)
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 35588ecf811a3d4a37da206a7e853781a93ab36b 48732 ocaml-domainslib_0.5.2-3.git.tar.xz
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Checksums-Sha256:
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Files:
 0bff77bb4f548e17397d9434cc2ca6bc 2645 ocaml optional ocaml-domainslib_0.5.2-3.dsc
 14965e16d4660b37a0200294ce109267 3408 ocaml optional ocaml-domainslib_0.5.2-3.debian.tar.xz
 8df9f1bbe4171bfcbb5116b906ebc408 48732 ocaml None ocaml-domainslib_0.5.2-3.git.tar.xz
 947cef0012ba04111429fa84aae7d395 17760 ocaml optional ocaml-domainslib_0.5.2-3_source.buildinfo
Git-Tag-Info: tag=aedc4409c3324830639311affd86e66a17f0b217 fp=6de24e97eca886cc56e6250e21b8eef1b1893081
Git-Tag-Tagger: Stéphane Glondu <steph@glondu.net>
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