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 (
@@ -440,6 +441,18 @@ def run(self, options, args):
             message = create_os_error_message(
                 error, show_traceback, options.use_user_site,
             )
+            if (WINDOWS and error.errno == errno.ENOENT and error.filename and
+                    len(error.filename) >= 260):
+                logger.warning(
+                    'The following error can potentially be caused '
+                    'because Long Paths is disabled on your system. '
+                    'Please set LongPathsEnabled to 1 in the '
+                    'registry and try again. For further instructions '
+                    'please refer to the documentation: https://docs.'
+                    'microsoft.com/en-us/windows/win32/fileio/maximum'
+                    '-file-path-limitation?tabs=cmd#enable-long-paths'
+                    '-in-windows-10-version-1607-and-later'
+                )
             logger.error(message, exc_info=show_traceback)  # noqa
 
             return ERROR