diff -r 57875cf423c9 -r 2372284d9457 mercurial/pycompat.py
--- a/mercurial/pycompat.py	Sat Oct 05 10:29:34 2019 -0400
+++ b/mercurial/pycompat.py	Sun Oct 06 09:45:02 2019 -0400
@@ -17,8 +17,8 @@
 import sys
 import tempfile
 
-ispy3 = (sys.version_info[0] >= 3)
-ispypy = (r'__pypy__' in sys.builtin_module_names)
+ispy3 = sys.version_info[0] >= 3
+ispypy = r'__pypy__' in sys.builtin_module_names
 
 if not ispy3:
     import cookielib
@@ -32,6 +32,8 @@
 
     def future_set_exception_info(f, exc_info):
         f.set_exception_info(*exc_info)
+
+
 else:
     import concurrent.futures as futures
     import http.cookiejar as cookielib
@@ -44,9 +46,11 @@
     def future_set_exception_info(f, exc_info):
         f.set_exception(exc_info[0])
 
+
 def identity(a):
     return a
 
+
 def _rapply(f, xs):
     if xs is None:
         # assume None means non-value of optional data
@@ -57,6 +61,7 @@
         return type(xs)((_rapply(f, k), _rapply(f, v)) for k, v in xs.items())
     return f(xs)
 
+
 def rapply(f, xs):
     """Apply function recursively to every item preserving the data structure
 
@@ -80,6 +85,7 @@
         return xs
     return _rapply(f, xs)
 
+
 if ispy3:
     import builtins
     import functools
@@ -195,8 +201,11 @@
         def __new__(cls, s=b''):
             if isinstance(s, bytestr):
                 return s
-            if (not isinstance(s, (bytes, bytearray))
-                and not hasattr(s, u'__bytes__')):  # hasattr-py3-only
+            if not isinstance(
+                s, (bytes, bytearray)
+            ) and not hasattr(  # hasattr-py3-only
+                s, u'__bytes__'
+            ):
                 s = str(s).encode(u'ascii')
             return bytes.__new__(cls, s)
 
@@ -270,6 +279,7 @@
         @functools.wraps(f)
         def w(object, name, *args):
             return f(object, sysstr(name), *args)
+
         return w
 
     # these wrappers are automagically imported by hgloader
@@ -296,8 +306,7 @@
         shortlist = shortlist.decode('latin-1')
         namelist = [a.decode('latin-1') for a in namelist]
         opts, args = orig(args, shortlist, namelist)
-        opts = [(a[0].encode('latin-1'), a[1].encode('latin-1'))
-                for a in opts]
+        opts = [(a[0].encode('latin-1'), a[1].encode('latin-1')) for a in opts]
         args = [a.encode('latin-1') for a in args]
         return opts, args
 
@@ -347,8 +356,7 @@
     bytesurl = identity
 
     # this can't be parsed on Python 3
-    exec('def raisewithtb(exc, tb):\n'
-         '    raise exc, None, tb\n')
+    exec('def raisewithtb(exc, tb):\n' '    raise exc, None, tb\n')
 
     def fsencode(filename):
         """
@@ -359,8 +367,7 @@
         if isinstance(filename, str):
             return filename
         else:
-            raise TypeError(
-                r"expect str, not %s" % type(filename).__name__)
+            raise TypeError(r"expect str, not %s" % type(filename).__name__)
 
     # In Python 2, fsdecode() has a very chance to receive bytes. So it's
     # better not to touch Python 2 part as it's already working fine.
@@ -412,23 +419,30 @@
 isposix = osname == b'posix'
 iswindows = osname == b'nt'
 
+
 def getoptb(args, shortlist, namelist):
     return _getoptbwrapper(getopt.getopt, args, shortlist, namelist)
 
+
 def gnugetoptb(args, shortlist, namelist):
     return _getoptbwrapper(getopt.gnu_getopt, args, shortlist, namelist)
 
+
 def mkdtemp(suffix=b'', prefix=b'tmp', dir=None):
     return tempfile.mkdtemp(suffix, prefix, dir)
 
+
 # text=True is not supported; use util.from/tonativeeol() instead
 def mkstemp(suffix=b'', prefix=b'tmp', dir=None):
     return tempfile.mkstemp(suffix, prefix, dir)
 
+
 # mode must include 'b'ytes as encoding= is not supported
-def namedtempfile(mode=b'w+b', bufsize=-1, suffix=b'', prefix=b'tmp', dir=None,
-                  delete=True):
+def namedtempfile(
+    mode=b'w+b', bufsize=-1, suffix=b'', prefix=b'tmp', dir=None, delete=True
+):
     mode = sysstr(mode)
     assert r'b' in mode
-    return tempfile.NamedTemporaryFile(mode, bufsize, suffix=suffix,
-                                       prefix=prefix, dir=dir, delete=delete)
+    return tempfile.NamedTemporaryFile(
+        mode, bufsize, suffix=suffix, prefix=prefix, dir=dir, delete=delete
+    )