Sphinx builds "succeed" despite errors

I’m building my document with sphinx and rst2pdf 0.97.

When the package fontconfig is not installed, the build output shows an error, but the build succeeds with exit code 0 and a zero-byte document is produced. Probably the error should be caught and the build made to fail.

writing domjudge-team-manual... 
[ERROR] pdfbuilder.py:149 [Errno 2] No such file or directory: 'fc-match'
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/rst2pdf/pdfbuilder.py", line 146, in write
    docwriter.write(doctree, destination)
  File "/usr/lib/python3/dist-packages/docutils/writers/__init__.py", line 78, in write
    self.translate()
  File "/usr/lib/python3/dist-packages/rst2pdf/pdfbuilder.py", line 625, in translate
    createpdf.RstToPdf(sphinx=True,
  File "/usr/lib/python3/dist-packages/rst2pdf/createpdf.py", line 173, in __init__
    self.loadStyles(stylesheets)
  File "/usr/lib/python3/dist-packages/rst2pdf/createpdf.py", line 273, in loadStyles
    self.styles = sty.StyleSheet(styleSheets,
  File "/usr/lib/python3/dist-packages/rst2pdf/styles.py", line 358, in __init__
    fontList = findfonts.autoEmbed(style[key])
  File "/usr/lib/python3/dist-packages/rst2pdf/findfonts.py", line 322, in autoEmbed
    variants = findTTFont(fname)
  File "/usr/lib/python3/dist-packages/rst2pdf/findfonts.py", line 214, in findTTFont
    family = get_family(fname)
  File "/usr/lib/python3/dist-packages/rst2pdf/findfonts.py", line 178, in get_family
    data = make_string(subprocess.check_output(["fc-match", query]))
  File "/usr/lib/python3.8/subprocess.py", line 411, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/usr/lib/python3.8/subprocess.py", line 489, in run
    with Popen(*popenargs, **kwargs) as process:
  File "/usr/lib/python3.8/subprocess.py", line 854, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.8/subprocess.py", line 1702, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'fc-match'
FAILED
build succeeded.

[thijskh]

I have a hardish time reproducing the original issue. I am fine with closing this now that there’s a concrete improvement in the code base. I’ll be sure to let you know if I have (similar) issues in the future.

[stephenfin]

I’m able to reproduce this problem on a cloud Ubuntu 20.04 image, which comes with a pretty minimal amount of packages (I suspect the cloud Fedora images would have the same issues). I don’t think the real issue here is that running things without this package causes a failure or even that we don’t have this requirement documented (though that is certainly an issue). Rather, it’s that the build succeeds despite this failure. I recall seeing a similar issue about the return code for rst2pdf being 0 even when there’s an issue. That’s what we need to solve, IMO.