bug#52801: Guile misbehaves in case of escapes and carriage returns, sometimes breaking "guix pull"

[Ludovic Courtès]

Hi,

Grigory Shepelev <shegeley@gmail.com> skribis:

> shegeley@zone51 ~$ guix pull
> Updating channel 'nonguix' from Git repository at 
> 'https://gitlab.com/nonguix/nonguix'...
> Updating channel 'guix' from Git repository at 
> 'https://git.savannah.gnu.org/git/guix.git'...
> Building from these channels:
>   guix      https://git.savannah.gnu.org/git/guix.git 2495582
>   nonguix   https://gitlab.com/nonguix/nonguix        39e4b41
> Computing Guix derivation for 'x86_64-linux'... -ice-9/read.scm:126:4: In 
> procedure read-string:
> gnu/packages/virtualization.scm:640:1: invalid character in escape sequence: 
> #\return
> guix pull: error: You found a bug: the program 
> '/gnu/store/w1hd6ab7f92y0f2r1ah4yyvi205a71bc-compute-guix-derivation'
> failed to compute the derivation for Guix (version: 
> "2495582e08cf411163f0799d290fda5101141949"; system: "x86_64-linux";
> host version: "1dfe8c372163d481ebebb97dd3b4cafa49906b28"; pull-version: 1).

Maxime Devos <maximedevos@telenet.be> skribis:

> Seems like an instance of <https://issues.guix.gnu.org/52559#15>.
> I took the liberty of renaming the bug report appropriately.
>
> Anyway, here's the minimal reproducer:
>
> Run the following in a REPL:
> (call-with-input-string "\"Hello\\\rcarriage return!\"" read)
> ;; --> invalid character in escape sequence: #\return

That’s expected.  Conversely, this one works:

  (call-with-input-string "\"Hello \\\nnewline!\"" read)

What was in gnu/packages/virtualization.scm:640:1 at that point?

--8<---------------cut here---------------start------------->8---
$ git ls-tree 2495582e08cf411163f0799d290fda5101141949 -- gnu/packages
040000 tree 8070c9587f76797cf16800522688ded39c956d00    gnu/packages
$ git ls-tree 8070c9587f76797cf16800522688ded39c956d00 |grep virtuali
100644 blob 20ffb4a481239349078e2a2864d1bd873dfcd143    virtualization.scm
$ git show 20ffb4a481239349078e2a2864d1bd873dfcd143 |head -649 |tail -10
                "/run/setuid-programs:/run/current-system/profile/sbin:\
/run/current-system/profile/bin"))))
         (add-after 'bootstrap 'patch-sphinx-version-detection
           (lambda _
             ;; The build system runs 'sphinx-build --version' to verify that
             ;; the Sphinx is recent enough, but does not expect the
             ;; .sphinx-build-real executable name created by the Sphinx 
wrapper.
             (substitute* "configure"
               (("\\$SPHINX --version 2>&1")
                "$SPHINX --version 2>&1 \
--8<---------------cut here---------------end--------------->8---

AFAICS, this was a regular \n (not \r) following backslash.

Did the issue magically disappear?

Grigory, could it be that libgit2 somehow converted \n to \r\n on your
machine, or that you manually accesses files under
~/.cache/guix/checkouts?

Thanks,
Ludo’.