Cannot install Ciao in Ubuntu 25.10

[amato-gianluca]

Hello,
I am trying to install Ciao Prolog on a system with Ubuntu 25.10. Unfortunately, the one-liner

curl https://ciao-lang.org/boot -sSfL | sh

with all default options terminates with the following error:

=> core.engine: building [bin]
   compiling ciaoengine.LINUXx86_64 (engine)
/home/amato/.ciaoroot/v1.25.0-m1/core/bootstrap/ciaoc.car/ciaoc.sta: 5: exec: /home/amato/.ciaoroot/v1.25.0-m1/build-boot/eng/ciaoengine/objs/BOOT/ciaoengine: not found
{ERROR: No handle found for thrown exception error(return_code(127,pcall(/home/amato/.ciaoroot/v1.25.0-m1/core/bootstrap/ciaoc.car/ciaoc.sta,[-c,/home/amato/.ciaoroot/v1.25.0-m1/core/engine/ciaoengine.pl],[env([CIAOALIASPATH=,CIAOROOT=/home/amato/.ciaoroot/v1.25.0-m1,CIAOHDIR=/home/amato/.ciaoroot/v1.25.0-m1/build-boot/eng/ciaoengine/include,CIAOENGINE=/home/amato/.ciaoroot/v1.25.0-m1/build-boot/eng/ciaoengine/objs/BOOT/ciaoengine]),cwd(/home/amato/.ciaoroot/v1.25.0-m1/core/engine)])),process_join/1)}

Note that installation works flawlessly in both Ubuntu 24.04 and Fedora 43.

[jfmc]

Hi Gianluca,
I currently do not have access to any machine with that OS, we'll check as soon as possible.
Meanwhile, could you check if the manual installation (clone git repo + compile) works in Ubuntu 25.10?

[amato-gianluca]

Hi Jose,
unfortunately I have the same problem with the source code distribution. Installation fails when launching ./ciao-boot.sh configure with exactly the same error as before. I added a set -x command at the beginning of builder/sh_src/build_car.sh to see the execution trace of the script, and the precise command causing the error is:

CIAOPATH=/home/amato/ciao CIAOALIASPATH=ciaobld=/home/amato/ciao/builder/src CIAOROOT=/home/amato/ciao CIAOHDIR=/home/amato/ciao/build-boot/eng/include CIAOENGINE=/home/amato/ciao/build-boot/eng/objs/BOOT/ciaoengine /home/amato/ciao/build-boot/eng/objs/BOOT/ciaoengine build -C -b /home/amato/ciao/build-boot/bin/ciao_builder.sta

It seems the file build-boot/eng/ciaoengine/objs/BOOT/ciaoengine does not get created, while build-boot/eng/objs/BOOT/ciaoengine is correctly there.

[jfmc]

Thanks or reporting, we have reproduced the same (wrong) results here.

I suspect that it may be due to Ubuntu 25.10 transition to the Rust rewrite of GNU coreutils, but I've not located the problem yet.

[jfmc]

It seems that this is a bug in the Rust rewrite of coreutils:

# gnudirname a/b/.
a/b
# dirname a/b/.
a

The GNU implementation is compatible with POSIX and the Rust one seems to be buggy. I've submitted an issue to their project:

uutils/coreutils#10508

This is the expected behavior also in Python os.path.dirname and Ciao dirname/3 predicate.

Rather than introducing a workaround in Ciao, I'd like to see if uutils/Ubuntu can fix their code... It looks like a serious bug, or unnecessary incompatibility, and that it may break a lot of things out there.

If possible, I'd uninstall Rust-based coreutils and go back to the original and well tested GNU version meanwhile.

[amato-gianluca]

Thanks for your investigation: I subscribed to the bug in the Rust coreutils project. My personal workaround was to copy the Ciao binaries from my Fedora installation. It works, but I will try the workaround you suggest which seems more solid. Thanks again, --gianluca

…

On Tue, Jan 27, 2026 at 12:54 PM Jose F. Morales ***@***.***> wrote: *jfmc* left a comment (ciao-lang/ciao#114) <#114 (comment)> It seems that this is a bug in the Rust rewrite of coreutils: # gnudirname a/b/. a/b # dirname a/b/. a The GNU implementation is compatible with POSIX and the Rust one seems to be buggy. I've submitted an issue to their project: uutils/coreutils#10508 <uutils/coreutils#10508> This is the expected behavior also in Python os.path.dirname and Ciao dirname/3 predicate. Rather than introducing a workaround in Ciao, I'd like to see if uutils/Ubuntu can fix their code... It looks like a serious bug, or unnecessary incompatibility, and that it may break a lot of things out there. If possible, I'd uninstall Rust-based coreutils and go back to the original and well tested GNU version meanwhile. — Reply to this email directly, view it on GitHub <#114 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAGUR3EWAT6FUZXK32LMJ5T4I5GYJAVCNFSM6AAAAACR5GXLJ6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTQMBUG43TANBVGI> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[jfmc]

It seems to be already fixed in uutils/coreutils#8936

Ubuntu 25.10 comes with uutils 0.2.2, which is already very old and buggy. It can be replaced with GNU coreutils with a command like apt-get remove coreutils-from-uutils --allow-remove-essential (make sure that the proposed update plan includes installing coreutils-from-gnu).