 +                     make_install_requirement, clean_requires_python)
 +
  from .base import BaseRepository
-
-
+ 
+ 
 @@ -37,6 +47,45 @@ except ImportError:
      from pip.wheel import WheelCache
-
-
+ 
+ 
 +class HashCache(SafeFileCache):
 +    """Caches hashes of PyPI artifacts so we do not need to re-download them
 +

+            return set(self._json_dep_cache[ireq])
+        except Exception:
+            return set()

     def get_dependencies(self, ireq):
+        json_results = set()
+

             reqset.cleanup_files()
+
         return set(self._dependencies_cache[ireq])
 
     def get_hashes(self, ireq):
@@ -210,6 +434,10 @@ class PyPIRepository(BaseRepository):
         if ireq.editable:
             return set()
 
+        vcs = VcsSupport()
+        if ireq.link and ireq.link.scheme in vcs.all_schemes and 'ssh' in ireq.link.scheme:
+            return set()
