bug#79479: Issue with substring/shared

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On Sun, Sep 21, 2025 at 12:47=E2=80=AFAM Nikolaos Chatzikonstantinou
<[email protected]> wrote:
>
> Hello bug-guile,
>
> I have a structure (srfi srfi-9 gnu) that keeps parts of strings in a
> binary tree (it's a rope). The intention was to have it immutable, so
> I used substring/shared. I kept getting errors on my unit tests when I
> referenced individual characters; I could not replicate these errors
> on the REPL. Eventually I realized that substring/shared caused them.

I want to offer a small (<100 LoC) reproducible example now. I'm using
3.0.10. Try to run the test suite with autocompilation disabled
(--no-auto-compile), and you should get failure (if success, try
running again, rarely it succeeds.) If you compile the test.scm file,
then it should work fine.

I am not sure that I can figure this one out myself further, but
somehow it is related to my projects tests being left uncompiled. Does
anyone have an insight to the problem here?

Regards,
Nikolaos Chatzikonstantinou

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