From 4beec5c6b9122f36fdc85801d26fee619fb228ae Mon Sep 17 00:00:00 2001
From: Wyatt Hoodes <hoodesw@hawaii.edu>
Date: Tue, 30 Jul 2019 08:58:48 -1000
Subject: [PATCH] typing: Use TYPE_CHECKING when dealing with cyclic
 dependencies.

---
 tools/coveragerc              | 2 ++
 zerver/lib/cache.py           | 5 +++--
 zerver/lib/test_helpers.py    | 4 ++--
 zerver/tornado/descriptors.py | 4 ++--
 4 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/tools/coveragerc b/tools/coveragerc
index 30ea2a067f..cb97c4ef4d 100644
--- a/tools/coveragerc
+++ b/tools/coveragerc
@@ -13,6 +13,8 @@ exclude_lines =
     def __str__[(]self[)] -> .*:
     # Don't require coverage for errors about unsupported webhook event types
     raise UnexpectedWebhookEventType
+    # Don't require coverage for blocks only run when type-checking
+    if TYPE_CHECKING:
 
 [run]
 omit =
diff --git a/zerver/lib/cache.py b/zerver/lib/cache.py
index d5b511ff7e..d2d7f3d27c 100644
--- a/zerver/lib/cache.py
+++ b/zerver/lib/cache.py
@@ -9,7 +9,8 @@ from django.db.models import Q
 from django.core.cache.backends.base import BaseCache
 from django.http import HttpRequest
 
-from typing import Any, Callable, Dict, Iterable, List, Optional, TypeVar, Tuple
+from typing import Any, Callable, Dict, Iterable, List, \
+    Optional, TypeVar, Tuple, TYPE_CHECKING
 
 from zerver.lib.utils import statsd, statsd_key, make_safe_digest
 import time
@@ -19,7 +20,7 @@ import sys
 import os
 import hashlib
 
-if False:
+if TYPE_CHECKING:
     # These modules have to be imported for type annotations but
     # they cannot be imported at runtime due to cyclic dependency.
     from zerver.models import UserProfile, Realm, Message
diff --git a/zerver/lib/test_helpers.py b/zerver/lib/test_helpers.py
index 7e6b4a4854..d75f18def8 100644
--- a/zerver/lib/test_helpers.py
+++ b/zerver/lib/test_helpers.py
@@ -1,7 +1,7 @@
 from contextlib import contextmanager
 from typing import (
     Any, Callable, Dict, Generator, Iterable, Iterator, List, Mapping,
-    Optional, Tuple, Union, IO, TypeVar
+    Optional, Tuple, Union, IO, TypeVar, TYPE_CHECKING
 )
 
 from django.core import signing
@@ -38,7 +38,7 @@ from zerver.models import (
     UserProfile,
 )
 
-if False:
+if TYPE_CHECKING:
     # Avoid an import cycle; we only need these for type annotations.
     from zerver.lib.test_classes import ZulipTestCase, MigrationsTestCase
 
diff --git a/zerver/tornado/descriptors.py b/zerver/tornado/descriptors.py
index a911b92a9d..032cd19d25 100644
--- a/zerver/tornado/descriptors.py
+++ b/zerver/tornado/descriptors.py
@@ -1,6 +1,6 @@
-from typing import Dict, Optional
+from typing import Dict, Optional, TYPE_CHECKING
 
-if False:
+if TYPE_CHECKING:
     from zerver.tornado.event_queue import ClientDescriptor
 
 descriptors_by_handler_id = {}  # type: Dict[int, ClientDescriptor]