avoid using shallow wheels for non-remote file paths

src/pip/_internal/network/shallow/httpfile.py

@@ -13,12 +13,16 @@
     from typing import Any, Optional
 
 
+def url_is_remote(url):
+    # type: (str) -> bool
+    return get_url_scheme(url) in ['http', 'https']
+
+
 class Url(namedtuple('Url', ['url'])):
 
     def __new__(cls, url):
         # type: (str) -> Url
-        scheme = get_url_scheme(url)
-        assert scheme in ["http", "https"]
+        assert url_is_remote(url)
         return super(Url, cls).__new__(cls, url)
 
 

src/pip/_internal/operations/prepare.py

@@ -25,6 +25,7 @@
     PreviousBuildDirError,
     VcsHashUnsupported,
 )
+from pip._internal.network.shallow.httpfile import url_is_remote
 from pip._internal.utils.filesystem import copy2_fixed
 from pip._internal.utils.hashes import MissingHashes
 from pip._internal.utils.logging import indent_log
@@ -406,7 +407,7 @@ def prepare_linked_requirement(
             download_dir = self.wheel_download_dir
 
         if link.is_wheel:
-            if self.use_shallow_wheels:
+            if self.use_shallow_wheels and url_is_remote(link.url):
                 return ShallowWheelDistribution(
                     req, self.downloader, download_dir)
             if download_dir:

src/pip/_internal/req/req_set.py

@@ -68,6 +68,7 @@ def perform_all_final_hydration(self):
             return
 
         exceptions = []
+
         def do_hydrate(dist):
             # type: (DistributionNeedingFinalHydration) -> None
             try: