From b16a68cf585ff2dd34661cd9b1e846166eb90edf Mon Sep 17 00:00:00 2001
From: hauntsaninja <>
Date: Sat, 21 Nov 2020 21:59:53 -0800
Subject: [PATCH] fix package root validation

---
 mypy/main.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mypy/main.py b/mypy/main.py
index ddabfc0fbeb17..02d7dec148a54 100644
--- a/mypy/main.py
+++ b/mypy/main.py
@@ -974,7 +974,6 @@ def process_package_roots(fscache: Optional[FileSystemCache],
     assert fscache is not None  # Since mypy doesn't know parser.error() raises.
     # Do some stuff with drive letters to make Windows happy (esp. tests).
     current_drive, _ = os.path.splitdrive(os.getcwd())
-    dotdotslash = os.pardir + os.sep
     package_root = []
     for root in options.package_root:
         if os.path.isabs(root):
@@ -985,7 +984,7 @@ def process_package_roots(fscache: Optional[FileSystemCache],
         # Empty package root is always okay.
         if not root:
             root = os.curdir
-        if os.path.relpath(root).startswith(dotdotslash):
+        if os.path.relpath(root).split(os.sep)[0] == os.pardir:
             parser.error("Package root cannot be above current directory: %r" % root)
         root = os.path.normpath(os.path.abspath(root))
         if not root.endswith(os.sep):