hg failing if external repo is broken

[Massimo-B]

I have /.hg in my root fs of Gentoo Linux, tracking almost /etc and other files. And if something is broken with that external repo, all Python installations by the package manager inside of it's building sandbox in /var/tmp/portage are failing like this:

writing dependency_links to python_mimeparse.egg-info/dependency_links.txt
abort: No such file or directory: '/boot/config'
Traceback (most recent call last):
  File "setup.py", line 50, in <module>
    long_description=read('README.rst')
  File "/usr/lib64/python2.7/site-packages/setuptools/__init__.py", line 145, in setup
    return distutils.core.setup(**attrs)
  File "/usr/lib64/python2.7/distutils/core.py", line 151, in setup
    dist.run_commands()
  File "/usr/lib64/python2.7/distutils/dist.py", line 953, in run_commands
    self.run_command(cmd)
  File "/usr/lib64/python2.7/distutils/dist.py", line 972, in run_command
    cmd_obj.run()
  File "/usr/lib64/python2.7/site-packages/setuptools/command/install.py", line 61, in run
    return orig.install.run(self)
  File "/usr/lib64/python2.7/distutils/command/install.py", line 575, in run
    self.run_command(cmd_name)
  File "/usr/lib64/python2.7/distutils/cmd.py", line 326, in run_command
    self.distribution.run_command(command)
  File "/usr/lib64/python2.7/distutils/dist.py", line 972, in run_command
    cmd_obj.run()
  File "/usr/lib64/python2.7/site-packages/setuptools/command/install_egg_info.py", line 34, in run
    self.run_command('egg_info')
  File "/usr/lib64/python2.7/distutils/cmd.py", line 326, in run_command
    self.distribution.run_command(command)
  File "/usr/lib64/python2.7/distutils/dist.py", line 972, in run_command
    cmd_obj.run()
  File "/usr/lib64/python2.7/site-packages/setuptools/command/egg_info.py", line 296, in run
    self.find_sources()
  File "/usr/lib64/python2.7/site-packages/setuptools/command/egg_info.py", line 303, in find_sources
    mm.run()
  File "/usr/lib64/python2.7/site-packages/setuptools/command/egg_info.py", line 534, in run
    self.add_defaults()
  File "/usr/lib64/python2.7/site-packages/setuptools/command/egg_info.py", line 574, in add_defaults
    rcfiles = list(walk_revctrl())
  File "/usr/lib64/python2.7/site-packages/setuptools/command/sdist.py", line 20, in walk_revctrl
    for item in ep.load()(dirname):
  File "/usr/lib64/python2.7/site-packages/setuptools_scm/integration.py", line 27, in find_files
    res = command(path)
  File "/usr/lib64/python2.7/site-packages/setuptools_scm/file_finder_hg.py", line 46, in hg_find_files
    hg_files, hg_dirs = _hg_ls_files_and_dirs(toplevel)
  File "/usr/lib64/python2.7/site-packages/setuptools_scm/file_finder_hg.py", line 29, in _hg_ls_files_and_dirs
    ["hg", "files"], cwd=toplevel, universal_newlines=True
  File "/usr/lib64/python2.7/subprocess.py", line 223, in check_output
    raise CalledProcessError(retcode, cmd, output=output)
subprocess.CalledProcessError: Command '['hg', 'files']' returned non-zero exit status 255

setuptools should be completely independent from outside Mercurial repos or maybe have an option to ignore that like this:

--- a/src/setuptools_scm/file_finder_hg.py      2019-08-01 08:24:15.060553831 +0200
+++ b/src/setuptools_scm/file_finder_hg.py      2019-08-01 08:26:11.334617120 +0200
@@ -41,7 +41,11 @@
 
 def hg_find_files(path=""):
     toplevel = _hg_toplevel(path)
     if not toplevel:
         return []
+    # SETUPTOOLS_SCM_IGNORE_VCS_ROOTS is a ':'-separated list of VCS roots to ignore.
+    # Example: SETUPTOOLS_SCM_IGNORE_VCS_ROOTS=/var:/etc:/home/me
+    if toplevel in os.environ.get('SETUPTOOLS_SCM_IGNORE_VCS_ROOTS', '').split(':'):
+        return []
     hg_files, hg_dirs = _hg_ls_files_and_dirs(toplevel)
     return scm_find_files(path, hg_files, hg_dirs)

[RonnyPfannschmidt]

thanks for the input

the posted patch looks good, if you make it a pr with a note in the readme and a small test we can do a release of that quickly

an optional followup would be to move it to a utility function so we can use it for git as well

[Massimo-B]

I'm no python developer. As far as I tested that on Gentoo with
echo 'SETUPTOOLS_SCM_IGNORE_VCS_ROOTS="/"' >> /etc/portage/make.conf
it is working.
Please consider a release.

[RonnyPfannschmidt]

Will take a while, I'm currently on vacation

[Massimo-B]

Thank you.