dev_settings: Move prod_settings_template import to configured_settings.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

tools/linter_lib/pyflakes.py

@@ -16,12 +16,11 @@ def check_pyflakes(files: List[str], options: argparse.Namespace) -> bool:
         ("scripts/lib/pythonrc.py",
          " import *' used; unable to detect undefined names"),
 
-        # Special dev_settings.py import
-        ('', "from .prod_settings_template import *"),
-
         ("settings.py", "settings import *' used; unable to detect undefined names"),
+        ("settings.py", "'from .prod_settings_template import *' used; unable to detect undefined names"),
         ("settings.py", "may be undefined, or defined from star imports"),
         ("settings.py", "settings.*' imported but unused"),
+        ("settings.py", "'.prod_settings_template.*' imported but unused"),
 
         # Sphinx adds `tags` specially to the environment when running conf.py.
         ("docs/conf.py", "undefined name 'tags'"),

zproject/configured_settings.py

@@ -13,4 +13,7 @@ from .config import PRODUCTION
 if PRODUCTION:
     from .prod_settings import *  # isort: skip
 else:
+    # For the Dev VM environment, we use the same settings as the
+    # sample prod_settings.py file, with a few exceptions.
+    from .prod_settings_template import *  # isort: skip
     from .dev_settings import *  # isort: skip

zproject/dev_settings.py

@@ -1,9 +1,6 @@
-# For the Dev VM environment, we use the same settings as the
-# sample prod_settings.py file, with a few exceptions.
-from .prod_settings_template import *
 import os
 import pwd
-from typing import Set
+from typing import Optional, Set, Tuple
 
 from .config import DEPLOY_ROOT
 
@@ -43,7 +40,7 @@ ALLOWED_HOSTS = ['*']
 
 # Uncomment extra backends if you want to test with them.  Note that
 # for Google and GitHub auth you'll need to do some pre-setup.
-AUTHENTICATION_BACKENDS = (
+AUTHENTICATION_BACKENDS: Tuple[str, ...] = (
     'zproject.backends.DevAuthBackend',
     'zproject.backends.EmailAuthBackend',
     'zproject.backends.GitHubAuthBackend',