Warning for user when Windows default Path Limit is exceeded

news/10045.feature.rst

@@ -0,0 +1 @@
+Added a warning message for errors caused due to Long Paths being disabled on Windows.

src/pip/_internal/commands/install.py

@@ -26,6 +26,7 @@
 from pip._internal.req import install_given_reqs
 from pip._internal.req.req_install import InstallRequirement
 from pip._internal.req.req_tracker import get_requirement_tracker
+from pip._internal.utils.compat import WINDOWS
 from pip._internal.utils.distutils_args import parse_distutils_args
 from pip._internal.utils.filesystem import test_writable_dir
 from pip._internal.utils.misc import (
@@ -737,4 +738,17 @@ def create_os_error_message(error, show_traceback, using_user_site):
             parts.append(permissions_part)
         parts.append(".\n")
 
+    # Suggest the user to enable Long Paths if path length is
+    # more than 260
+    if (WINDOWS and error.errno == errno.ENOENT and error.filename and
+            len(error.filename) > 260):
+        parts.append(
+            "A potential cause to this error is "
+            "Long Paths being disabled on your system. "
+            "Please set LongPathsEnabled to 1 in the "
+            "registry and try again. For further instructions "
+            "please refer to the documentation: "
+            "https://pip.pypa.io/warnings/enable-long-paths"
+        )
+
     return "".join(parts).strip() + "\n"