[git-buildpackage] could gbp.config.GbpOptionParser.get_config_files handle GBP_CONF_FILES=''

[Guido Günther]

Hi Nish,
On Wed, Jan 10, 2018 at 02:21:52PM -0800, Nish Aravamudan wrote:
> For the reproducibility/debuggability of the git-ubuntu snap, we want to
> ensure that everyone will end up running certain commands (e.g., quilt,
> gbp) the same, no matter what their local configuration is. This is
> especially true for the importer itself, but is also true for other
> subcommands in our case.
> 
> I wonder if it might be reasonable to do:
> 
> diff --git a/gbp/config.py b/gbp/config.py
> index 8acf15da..c2feb2ab 100644
> --- a/gbp/config.py
> +++ b/gbp/config.py
> @@ -409,7 +409,7 @@ class GbpOptionParser(OptionParser):
>          >>> if conf_backup is not None: os.environ['GBP_CONF_FILES'] = conf_backup
>          """
>          envvar = os.environ.get('GBP_CONF_FILES')
> -        files = envvar.split(':') if envvar else [f for (f, _) in cls.def_config_files]
> +        files = envvar.split(':') if envvar is not None else [f for (f, _) in cls.def_config_files]
>          files = [os.path.expanduser(fname) for fname in files]
>          if no_local:
>              files = [fname for fname in files if fname.startswith('/')]
> 
> This would allow environments that wish to disable config file parsing
> (and thus behavioral variability) to juset set GBP_CONF_FILES='' rather
> than to something like '/dev/null' (which seems to be the only choice
> currently)?

Isn't it be more explicit to have GBP_CONF_FILES=/does/not/exist or
GBP_CONF_FILES=/dev/null than to make a distinction between unset or
set to the empty string? I'd rather not change the current behaviour.

Cheers,
 -- Guido