 +            self.options.build_isolation = build_isolation
          if self.options.cache_dir:
              self.options.cache_dir = normalize_path(self.options.cache_dir)
-
+ 
          self.options.require_hashes = False
          self.options.ignore_dependencies = False
-
+ 
 -        self.session = self.command._build_session(self.options)
 +        if session is None:
 +            session = self.command._build_session(self.options)

--- a/pipenv/patched/piptools/_compat/__init__.py
+++ b/pipenv/patched/piptools/_compat/__init__.py
@@ -4,7 +4,37 @@ from __future__ import absolute_import, division, print_function, unicode_litera

 import six

-from .pip_compat import PIP_VERSION, parse_requirements
+from .pip_compat import (
+    DEV_PKGS,

+    from pipenv.environments import PIPENV_CACHE_DIR as CACHE_DIR
+except ImportError:
+    CACHE_DIR = user_cache_dir("pipenv")
 
 # NOTE
 # We used to store the cache dir under ~/.pip-tools, which is not the
diff --git a/pipenv/patched/piptools/repositories/local.py b/pipenv/patched/piptools/repositories/local.py
