search: Add setting to control whether search pills are enabled.

This setting isn't intended to exist long term, but instead to make it
possible to merge our search pills code before we're ready to cut over
production environments to use it.

zerver/tests/test_home.py

@@ -162,6 +162,7 @@ class HomeTest(ZulipTestCase):
             "realm_waiting_period_threshold",
             "root_domain_uri",
             "save_stacktraces",
+            "search_pills_enabled",
             "server_generation",
             "server_inline_image_preview",
             "server_inline_url_embed_preview",

zerver/views/home.py

@@ -198,6 +198,7 @@ def home_real(request: HttpRequest) -> HttpResponse:
         password_min_length = settings.PASSWORD_MIN_LENGTH,
         password_min_guesses  = settings.PASSWORD_MIN_GUESSES,
         jitsi_server_url      = settings.JITSI_SERVER_URL,
+        search_pills_enabled  = settings.SEARCH_PILLS_ENABLED,
 
         # Misc. extra data.
         have_initial_messages = user_has_messages,

zproject/dev_settings.py

@@ -89,3 +89,5 @@ SENDFILE_BACKEND = 'sendfile.backends.development'
 ALWAYS_SEND_ALL_HOTSPOTS = False  # type: bool
 
 THUMBOR_URL = 'http://127.0.0.1:9995'
+
+SEARCH_PILLS_ENABLED = os.getenv('SEARCH_PILLS_ENABLED', False)

zproject/settings.py

@@ -221,6 +221,9 @@ DEFAULT_SETTINGS = {
     # in development mode.
     'ALWAYS_SEND_ALL_HOTSPOTS': False,
 
+    # In-development search pills feature.
+    'SEARCH_PILLS_ENABLED': False,
+
     # We use SubMessage for now-experimental features like
     # slash commands.
     'ALLOW_SUB_MESSAGES': DEVELOPMENT,