From 4cdf243406fb0ba412eb2e05d96d6be7fab6843b Mon Sep 17 00:00:00 2001
From: Fabio Zadrozny <fabiofz@gmail.com>
Date: Fri, 28 May 2021 11:40:23 -0300
Subject: [PATCH] Accept environment variables with different cases on Windows.
 Fixes #607

---
 src/debugpy/launcher/handlers.py | 10 ----------
 tests/debugpy/test_env.py        |  9 +++++----
 2 files changed, 5 insertions(+), 14 deletions(-)

diff --git a/src/debugpy/launcher/handlers.py b/src/debugpy/launcher/handlers.py
index da12ed077..0303741d1 100644
--- a/src/debugpy/launcher/handlers.py
+++ b/src/debugpy/launcher/handlers.py
@@ -79,16 +79,6 @@ def property_or_debug_option(prop_name, flag_name):
 
     env = os.environ.copy()
     env_changes = request("env", json.object((unicode, type(None))))
-    if sys.platform == "win32":
-        # Environment variables are case-insensitive on Win32, so we need to normalize
-        # both dicts to make sure that env vars specified in the debug configuration
-        # overwrite the global env vars correctly. If debug config has entries that
-        # differ in case only, that's an error.
-        env = {k.upper(): v for k, v in os.environ.items()}
-        n = len(env_changes)
-        env_changes = {k.upper(): v for k, v in env_changes.items()}
-        if len(env_changes) != n:
-            raise request.isnt_valid('Duplicate entries in "env"')
     if "DEBUGPY_TEST" in env:
         # If we're running as part of a debugpy test, make sure that codecov is not
         # applied to the debuggee, since it will conflict with pydevd.
diff --git a/tests/debugpy/test_env.py b/tests/debugpy/test_env.py
index 09fc7919c..7d7f44dc5 100644
--- a/tests/debugpy/test_env.py
+++ b/tests/debugpy/test_env.py
@@ -48,13 +48,14 @@ def code_to_debug():
             else:
                 assert env[varname] == "42"
         elif sys.platform == "win32":
-            # On Win32, variable names are case-insensitive, so debug config should
-            # replace the global env var even if there is a case mismatch.
+            # On Win32, although variable names are case-insensitive for matching, they're still
+            # case-preserving (and it's even possible to have something as Path and PATH even
+            # though later on one would override the other).
+            assert varname.lower() not in env
             if new_value is None:
-                assert varname not in env
+                assert env[varname] == "1"
             else:
                 assert env[varname] == "42"
-            assert varname.lower() not in env
         else:
             # On other platforms, variable names are case-sensitive, so case mismatch
             # should result in two different variables.