sentry: Initialize sentry in AppConfig ready hook.

This breaks an import cycle that prevented django-stubs from inferring
types for django.conf.settings.

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

zerver/apps.py

@@ -16,6 +16,12 @@ class ZerverConfig(AppConfig):
     name: str = "zerver"
 
     def ready(self) -> None:
+        if settings.SENTRY_DSN:  # nocoverage
+            from zproject.config import get_config
+            from zproject.sentry import setup_sentry
+
+            setup_sentry(settings.SENTRY_DSN, get_config("machine", "deploy_type", "development"))
+
         # We import zerver.signals here for the side effect of
         # registering the user_logged_in signal receiver.  This import
         # needs to be here (rather than e.g. at top-of-file) to avoid

zproject/computed_settings.py

@@ -1224,10 +1224,6 @@ TWO_FACTOR_PATCH_ADMIN = False
 
 # Allow the environment to override the default DSN
 SENTRY_DSN = os.environ.get("SENTRY_DSN", SENTRY_DSN)
-if SENTRY_DSN:
-    from .sentry import setup_sentry
-
-    setup_sentry(SENTRY_DSN, get_config("machine", "deploy_type", "development"))
 
 SCIM_SERVICE_PROVIDER = {
     "USER_ADAPTER": "zerver.lib.scim.ZulipSCIMUser",