bug#74484: reader syntax trouble across socket

[Christopher Howard]

Hi, I'm trying to troubleshoot some bugs in the venerable emacs-guix package, 
which you've probably heard of. In its default configuration, emacs-guix uses 
geiser to set up one Guile REPL (*Guix REPL*) to handle various guix 
operations, and tells it to --listen on a domain socket; and then it uses some 
comint functions to connect to the domain socket, to provide another Guile REPL 
(*Guix Internal REPL*) which it uses for various other guix operations while 
the main REPL is busy.

In guix bug#73462, I figured out that the bug was caused by, for some unknown 
reason, (guix gexp) reader syntax was working in the main REPL (*Guix REPL*) 
but not in the REPL that was over the socket (*Guix Internal REPL*). A work 
around is available, which is to run an extra ",re (guix gexp)" in the internal 
REPL buffer, and then after that it works fine, but I don't understand why that 
should be necessary. Can somebody help me figure if this is some kind of bug in 
Guile, or a different issue...?

This can be reproduced this one my system command line with the following 
commands. Of course, you would need to adjust for your own paths. On one 
terminal:

``` shell
christopher@theoden ~$ 
/gnu/store/g1fhmjs2mh8a0djfnyaha49ihb5cmkas-profile/bin/guile --no-auto-compile 
-L /home/christopher/Repos/emacs-guix/scheme -C 
/home/christopher/Repos/emacs-guix/scheme -L 
/home/christopher/.config/guix/current/share/guile/site/3.0 -C 
/home/christopher/.config/guix/current/lib/guile/3.0/site-ccache 
--listen=/tmp/test-socket
```

Then on another terminal:

```shell
christopher@theoden 
/gnu/store/pg7s74p1p3bf2k848xy4j0x8dcqv248l-netcat-openbsd-1.219-1/bin$ ./nc -U 
/tmp/test-socket
GNU Guile 3.0.9
Copyright (C) 1995-2023 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
scheme@(guile-user)> ,m (emacs-guix)
scheme@(emacs-guix)> (guix-command "pull")
Updating channel 'guix' from Git repository at 
'https://git.savannah.gnu.org/git/guix.git'...
Building from this channel:
  guix      https://git.savannah.gnu.org/git/guix.git   8a7bd21
ice-9/boot-9.scm:1685:16: In procedure raise-exception:
/gnu/store/hhnw8gr26smc267yy2hzk57p4b0g6iyb-guix-8a7bd21/build-aux/build-self.scm:84:18:
 Unknown # object: "#~"
```

But the same command, which is (guix-command "pull") works fine in the first 
terminal.

Some system information:

``` guix describe
Generation 153  Nov 20 2024 09:29:24    (current)
  guix 804f8b2
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: 804f8b2094f3214c5b129047c1b18a7779720496
```

``` guile --version
guile (GNU Guile) 3.0.9
```

Regarding the sockets issue, there is another bug I have found related to the 
use of the socket based REPL, described in bug#74250, but that one is more 
difficult to point to a specific cause or try to blame on Guile.

-- 
📛 Christopher Howard
🚀 gemini://gem.librehacker.com
🌐 http://gem.librehacker.com

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