[PATCH 1 of 8 V2] context: don't use mutable default argument value

[Yuya Nishihara]

On Sun, 12 Mar 2017 21:57:33 -0700, Gregory Szorc wrote:
> # HG changeset patch
> # User Gregory Szorc <gregory.szorc at gmail.com>
> # Date 1489380642 25200
> #      Sun Mar 12 21:50:42 2017 -0700
> # Node ID 265102f455de6451e493024fb8a9f24d816ce1c2
> # Parent  1c48a8278b2f015fca607dfc652823560a5ac580
> context: don't use mutable default argument value
> 
> Mutable default argument values are a Python gotcha and can
> represent subtle, hard-to-find bugs. Lets rid our code base
> of them.
> 
> diff --git a/mercurial/context.py b/mercurial/context.py
> --- a/mercurial/context.py
> +++ b/mercurial/context.py
> @@ -298,10 +298,10 @@ class basectx(object):
>          '''
>          return subrepo.subrepo(self, path, allowwdir=True)
>  
> -    def match(self, pats=[], include=None, exclude=None, default='glob',
> +    def match(self, pats=None, include=None, exclude=None, default='glob',
>                listsubrepos=False, badfn=None):
>          r = self._repo
> -        return matchmod.match(r.root, r.getcwd(), pats,
> +        return matchmod.match(r.root, r.getcwd(), pats or [],
>                                include, exclude, default,
>                                auditor=r.nofsauditor, ctx=self,
>                                listsubrepos=listsubrepos, badfn=badfn)
> @@ -1515,16 +1515,16 @@ class workingctx(committablectx):
>                      self._repo.dirstate.normallookup(dest)
>                  self._repo.dirstate.copy(source, dest)
>  
> -    def match(self, pats=[], include=None, exclude=None, default='glob',
> +    def match(self, pats=None, include=None, exclude=None, default='glob',
>                listsubrepos=False, badfn=None):
>          r = self._repo
>  
>          # Only a case insensitive filesystem needs magic to translate user input
>          # to actual case in the filesystem.
>          if not util.fscasesensitive(r.root):
> -            return matchmod.icasefsmatcher(r.root, r.getcwd(), pats, include,
> -                                           exclude, default, r.auditor, self,
> -                                           listsubrepos=listsubrepos,
> +            return matchmod.icasefsmatcher(r.root, r.getcwd(), pats or [],
> +                                           include, exclude, default, r.auditor,
> +                                           self, listsubrepos=listsubrepos,
>                                             badfn=badfn)
>          return matchmod.match(r.root, r.getcwd(), pats,
                                                     ^^^^

Missed 'pats or []'. Fixed in-flight and queued the series, thanks.