mypy: Prohibit unreachable code.

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

mypy.ini

@@ -11,3 +11,4 @@ show_traceback = True
 warn_no_return = True
 warn_redundant_casts = True
 warn_unused_ignores = True
+warn_unreachable = True

zulip/integrations/codebase/zulip_codebase_config.py

@@ -1,3 +1,5 @@
+from typing import Optional
+
 # Change these values to configure authentication for your codebase account
 # Note that this is the Codebase API Username, found in the Settings page
 # for your account
@@ -23,14 +25,14 @@ ZULIP_TICKETS_STREAM_NAME = "tickets"
 
 # If properly installed, the Zulip API should be in your import
 # path, but if not, set a custom path below
-ZULIP_API_PATH = None
+ZULIP_API_PATH: Optional[str] = None
 
 # Set this to your Zulip API server URI
 ZULIP_SITE = "https://zulip.example.com"
 
 # If you wish to log to a file rather than stdout/stderr,
 # please fill this out your desired path
-LOG_FILE = None
+LOG_FILE: Optional[str] = None
 
 # This file is used to resume this mirror in case the script shuts down.
 # It is required and needs to be writeable.

zulip/integrations/codebase/zulip_codebase_mirror

@@ -293,8 +293,7 @@ def check_permissions() -> None:
         sys.stderr.write(str(e))
 
 if __name__ == "__main__":
-    if not isinstance(config.RESUME_FILE, str):
+    assert isinstance(config.RESUME_FILE, str), "RESUME_FILE path not given; refusing to continue"
-        sys.stderr.write("RESUME_FILE path not given; refusing to continue")
     check_permissions()
     if config.LOG_FILE:
         logging.basicConfig(filename=config.LOG_FILE, level=logging.WARNING)

zulip/integrations/git/zulip_git_config.py

@@ -41,7 +41,7 @@ def format_commit_message(author: Text, subject: Text, commit_id: Text) -> Text:
 
 ## If properly installed, the Zulip API should be in your import
 ## path, but if not, set a custom path below
-ZULIP_API_PATH = None
+ZULIP_API_PATH: Optional[str] = None
 
 # Set this to your Zulip server's API URI
 ZULIP_SITE = "https://zulip.example.com"

zulip/integrations/perforce/zulip_perforce_config.py

@@ -12,7 +12,7 @@ ZULIP_IGNORE_MISSING_STREAM = False
 
 # Set this to point at a p4web installation to get changelist IDs as links
 # P4_WEB = "https://p4web.example.com"
-P4_WEB = None
+P4_WEB: Optional[str] = None
 
 # commit_notice_destination() lets you customize where commit notices
 # are sent to with the full power of a Python function.
@@ -45,4 +45,4 @@ def commit_notice_destination(path: Text, changelist: int) -> Optional[Dict[Text
 
 ## If properly installed, the Zulip API should be in your import
 ## path, but if not, set a custom path below
-ZULIP_API_PATH = None
+ZULIP_API_PATH: Optional[str] = None

zulip/integrations/svn/zulip_svn_config.py

@@ -29,7 +29,7 @@ def commit_notice_destination(path: Text, commit: Text) -> Optional[Dict[Text, T
 
 ## If properly installed, the Zulip API should be in your import
 ## path, but if not, set a custom path below
-ZULIP_API_PATH = None
+ZULIP_API_PATH: Optional[str] = None
 
 # Set this to your Zulip server's API URI
 ZULIP_SITE = "https://zulip.example.com"

zulip/integrations/trac/zulip_trac_config.py

@@ -1,5 +1,7 @@
 # See zulip_trac.py for installation and configuration instructions
 
+from typing import Optional
+
 # Change these constants to configure the plugin:
 ZULIP_USER = "trac-bot@example.com"
 ZULIP_API_KEY = "0123456789abcdef0123456789abcdef"
@@ -23,7 +25,7 @@ TRAC_NOTIFY_FIELDS = ["description", "summary", "resolution", "comment", "owner"
 
 ## If properly installed, the Zulip API should be in your import
 ## path, but if not, set a custom path below
-ZULIP_API_PATH = None
+ZULIP_API_PATH: Optional[str] = None
 
 # Set this to your Zulip API server URI
 ZULIP_SITE = "https://zulip.example.com"

zulip_bots/zulip_bots/bots/virtual_fs/virtual_fs.py

@@ -15,7 +15,7 @@ class VirtualFsHandler:
     def usage(self) -> str:
         return get_help()
 
-    def handle_message(self, message: Dict[str, str], bot_handler: BotHandler) -> None:
+    def handle_message(self, message: Dict[str, Any], bot_handler: BotHandler) -> None:
         command = message['content']
         if command == "":
             command = "help"

zulip_bots/zulip_bots/run.py

@@ -83,7 +83,7 @@ def exit_gracefully_if_zulip_config_is_missing(config_file: Optional[str]) -> No
 
         sys.exit(1)
 
-def exit_gracefully_if_bot_config_file_does_not_exist(bot_config_file: str) -> None:
+def exit_gracefully_if_bot_config_file_does_not_exist(bot_config_file: Optional[str]) -> None:
     if bot_config_file is None:
         # This is a common case, just so succeed quietly. (Some
         # bots don't have third party configuration.)