Subject: Re: bug#30265: Fish embeds store file names in UCS-4/UTF-32 literal strings

From: Maxim Cournoyer <[email-masked]>
Date: Sun, 09 Oct 2022 23:38:43 -0400

Hi,

Mark H Weaver <[email-masked]> writes:

> John Soo <[email-masked]> writes:
>> I looked into it and I think a patch to fish might be required but I
>> got buried in other work.
>
> Note that commit 1bab9b9f17256a9e4f45f5b0cceb8b52e0a1b1ed (April 2021)
> added support in our grafting code to find and rewrite UTF-16 and UTF-32
> store references.  That might have mitigated or even eliminated the
> adverse effects of this bug.
>
> However, the Guix daemon's reference scanner still does not detect
> UTF-16/32 references.  This could be a problem if some store item is
> reachable *only* via UTF-16/32 store references, because "guix gc" might
> delete it even though it is still needed.
>
> However, if it is the case that every referenced store item is
> represented in ASCII or UTF-8 at least once, everything should work.
> Therefore, an easy workaround would be to add another phase that simply
> creates a file in the output(s) that contains ASCII or UTF-8 references
> to any needed store items.

Working with what I see (the fish build outputs results), the only UCS-4
references (either big or small endian) it registered to the store via
multi-byte encoded strings are:

--8<---------------cut here---------------start------------->8---
$ strings -e L /gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/bin/fish* | grep /gnu
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/share/doc/fish
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/share/fish
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/etc/fish
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/bin
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/bin
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/bin
strings -e B /gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/bin/fish* | grep /gnu
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/share/doc/fish
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/share/fish
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/etc/fish
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/bin
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/bin
/gnu/store/qfy1rxm1vzd68y9jvcvq4zzz0cnbla8i-fish-3.5.1/bin
--8<---------------cut here---------------end--------------->8---

No UCS-2 references are detected via 'strings'.

Thanks for having shared the history and background.

Closing.

-- 
Maxim