Read git tags using Scheme

[Noeck]

Hi,

I am using the function below which is adapted from
http://lilypondblog.org/2014/01/why-use-version-control-for-engraving-scores/#more-2151

While it works and the .ly files compile successfully, the function
issues a warning (?) I’d like to get rid of.

1) If the document is in a git directory, this is printed:

 Parsing...git: /…path/to…/lilypond-2.20.0-1/lilypond/usr/lib/libz.so.1:
 no version information available (required by git)

Where does it come from and why is it issued?
Doing `git --version` in bash does not issue it.

2) If the document is not in a git repository another log line is added:

 fatal: not a git repository (or any of the parent directories): .git

Which I understand but I’d like to hide it anyways because I want to use
the same file no matter if it is used with git or not.

Any ideas how to achieve this?

Cheers,
Joram


%%%% code

\version "2.20.0"

#(use-modules (ice-9 popen))
#(use-modules (ice-9 rdelim))

#(define (strsystem_internal cmd)
   (let* ((port (open-input-pipe cmd))
          (str (read-line port)))
     (close-pipe port)
     str))

#(define gitshort (let* ((res (strsystem_internal
  "git describe --long --dirty='+' | sed 's/-/./' | sed -r
's/-g[0-9a-f]+//g'")))
  (if (string? res) res "")))
% if (string? ... is my clumsy way to ensure it returns a string

\markup { "Version" \gitshort }