update vendored pipfile

Signed-off-by: Kenneth Reitz <me@kennethreitz.org>

pipenv/vendor/pipfile/api.py

@@ -16,37 +16,6 @@ def format_full_version(info):
     return version
 
 
-def walk_up(bottom):
-    """mimic os.walk, but walk 'up' instead of down the directory tree.
-    From: https://gist.github.com/zdavkeos/1098474
-    """
-
-    bottom = os.path.realpath(bottom)
-
-    # get files in current dir
-    try:
-        names = os.listdir(bottom)
-    except Exception:
-        return
-
-    dirs, nondirs = [], []
-    for name in names:
-        if os.path.isdir(os.path.join(bottom, name)):
-            dirs.append(name)
-        else:
-            nondirs.append(name)
-
-    yield bottom, dirs, nondirs
-
-    new_path = os.path.realpath(os.path.join(bottom, '..'))
-
-    # see if we are at the top
-    if new_path == bottom:
-        return
-
-    for x in walk_up(new_path):
-        yield x
-
 
 class PipfileParser(object):
     def __init__(self, filename='Pipfile'):
@@ -108,16 +77,13 @@ class Pipfile(object):
     def find(max_depth=3):
         """Returns the path of a Pipfile in parent directories."""
         i = 0
-        for c, d, f in walk_up(os.getcwd()):
+        for c, d, f in os.walk(os.getcwd(), topdown=False):
+            if i > max_depth:
+                raise RuntimeError('No Pipfile found!')
+            elif 'Pipfile' in f:
+                return os.path.join(c, 'Pipfile')
             i += 1
 
-            if i < max_depth:
-                if 'Pipfile':
-                    p = os.path.join(c, 'Pipfile')
-                    if os.path.isfile(p):
-                        return p
-        raise RuntimeError('No Pipfile found!')
-
     @classmethod
     def load(klass, filename):
         """Load a Pipfile from a given filename."""