Fix error in new AppEngine environments

Newer AppEngine environments don't define the SERVER_SOFTWARE env variable. Without this change, importing click dies with a KeyError. See related pull request for urllib3: urllib3/urllib3#1704
jab · Jan 31, 2020 · 8c5f779 · 8c5f779
1 parent 5234cc8
commit 8c5f779
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/click/_compat.py b/click/_compat.py
@@ -11,7 +11,7 @@
 MSYS2 = sys.platform.startswith('win') and ('GCC' in sys.version)
 # Determine local App Engine environment, per Google's own suggestion
 APP_ENGINE = ('APPENGINE_RUNTIME' in os.environ and
-              'Development/' in os.environ['SERVER_SOFTWARE'])
+              'Development/' in os.environ.get('SERVER_SOFTWARE', ''))
 WIN = sys.platform.startswith('win') and not APP_ENGINE and not MSYS2
 DEFAULT_COLUMNS = 80