Fix type errors and potentially unbound code in http.py

discord/http.py

@@ -42,6 +42,7 @@ from typing import (
     Tuple,
     Type,
     TypeVar,
+    Union,
 )
 from urllib.parse import quote as _uriquote
 import weakref
@@ -51,6 +52,7 @@ import aiohttp
 from .errors import HTTPException, Forbidden, NotFound, LoginFailure, DiscordServerError, GatewayNotFound
 from .gateway import DiscordClientWebSocketResponse
 from . import __version__, utils
+from .utils import MISSING
 
 log = logging.getLogger(__name__)
 
@@ -93,7 +95,7 @@ if TYPE_CHECKING:
     Response = Coroutine[Any, Any, T]
 
 
-async def json_or_text(response: aiohttp.ClientResponse) -> Any:
+async def json_or_text(response: aiohttp.ClientResponse) -> Union[Dict[str, Any], str]:
     text = await response.text(encoding='utf-8')
     try:
         if response.headers['content-type'] == 'application/json':
@@ -170,7 +172,7 @@ class HTTPClient:
     ) -> None:
         self.loop: asyncio.AbstractEventLoop = asyncio.get_event_loop() if loop is None else loop
         self.connector = connector
-        self.__session: Optional[aiohttp.ClientSession] = None  # filled in static_login
+        self.__session: aiohttp.ClientSession = MISSING  # filled in static_login
         self._locks: weakref.WeakValueDictionary = weakref.WeakValueDictionary()
         self._global_over: asyncio.Event = asyncio.Event()
         self._global_over.set()
@@ -223,7 +225,7 @@ class HTTPClient:
                 self._locks[bucket] = lock
 
         # header creation
-        headers = {
+        headers: Dict[str, str] = {
             'User-Agent': self.user_agent,
         }
 
@@ -254,6 +256,8 @@ class HTTPClient:
             # wait until the global lock is complete
             await self._global_over.wait()
 
+        response: Optional[aiohttp.ClientResponse] = None
+        data: Optional[Union[Dict[str, Any], str]] = None
         await lock.acquire()
         with MaybeUnlock(lock) as maybe_lock:
             for tries in range(5):
@@ -268,36 +272,36 @@ class HTTPClient:
                     kwargs['data'] = form_data
 
                 try:
-                    async with self.__session.request(method, url, **kwargs) as r:
+                    async with self.__session.request(method, url, **kwargs) as response:
-                        log.debug('%s %s with %s has returned %s', method, url, kwargs.get('data'), r.status)
+                        log.debug('%s %s with %s has returned %s', method, url, kwargs.get('data'), response.status)
 
                         # even errors have text involved in them so this is safe to call
-                        data = await json_or_text(r)
+                        data = await json_or_text(response)
 
                         # check if we have rate limit header information
-                        remaining = r.headers.get('X-Ratelimit-Remaining')
+                        remaining = response.headers.get('X-Ratelimit-Remaining')
-                        if remaining == '0' and r.status != 429:
+                        if remaining == '0' and response.status != 429:
                             # we've depleted our current bucket
-                            delta = utils._parse_ratelimit_header(r, use_clock=self.use_clock)
+                            delta = utils._parse_ratelimit_header(response, use_clock=self.use_clock)
                             log.debug('A rate limit bucket has been exhausted (bucket: %s, retry: %s).', bucket, delta)
                             maybe_lock.defer()
                             self.loop.call_later(delta, lock.release)
 
                         # the request was successful so just return the text/json
-                        if 300 > r.status >= 200:
+                        if 300 > response.status >= 200:
                             log.debug('%s %s has received %s', method, url, data)
                             return data
 
                         # we are being rate limited
-                        if r.status == 429:
+                        if response.status == 429:
-                            if not r.headers.get('Via'):
+                            if not response.headers.get('Via') or isinstance(data, str):
                                 # Banned by Cloudflare more than likely.
-                                raise HTTPException(r, data)
+                                raise HTTPException(response, data)
 
                             fmt = 'We are being rate limited. Retrying in %.2f seconds. Handled under the bucket "%s"'
 
                             # sleep a bit
-                            retry_after: float = data['retry_after']  # type: ignore
+                            retry_after: float = data['retry_after']
                             log.warning(fmt, retry_after, bucket)
 
                             # check if it's a global rate limit
@@ -318,19 +322,19 @@ class HTTPClient:
                             continue
 
                         # we've received a 500 or 502, unconditional retry
-                        if r.status in {500, 502}:
+                        if response.status in {500, 502}:
                             await asyncio.sleep(1 + tries * 2)
                             continue
 
                         # the usual error cases
-                        if r.status == 403:
+                        if response.status == 403:
-                            raise Forbidden(r, data)
+                            raise Forbidden(response, data)
-                        elif r.status == 404:
+                        elif response.status == 404:
-                            raise NotFound(r, data)
+                            raise NotFound(response, data)
-                        elif r.status == 503:
+                        elif response.status == 503:
-                            raise DiscordServerError(r, data)
+                            raise DiscordServerError(response, data)
                         else:
-                            raise HTTPException(r, data)
+                            raise HTTPException(response, data)
 
                 # This is handling exceptions from the request
                 except OSError as e:
@@ -340,11 +344,14 @@ class HTTPClient:
                         continue
                     raise
 
+            if response is not None:
                 # We've run out of retries, raise.
-            if r.status >= 500:
+                if response.status >= 500:
-                raise DiscordServerError(r, data)
+                    raise DiscordServerError(response, data)
 
-            raise HTTPException(r, data)
+                raise HTTPException(response, data)
+
+            raise RuntimeError('Unreachable code in HTTP handling')
 
     async def get_from_cdn(self, url: str) -> bytes:
         async with self.__session.get(url) as resp:
@@ -375,7 +382,7 @@ class HTTPClient:
             data = await self.request(Route('GET', '/users/@me'))
         except HTTPException as exc:
             self.token = old_token
-            if exc.response.status == 401:
+            if exc.status == 401:
                 raise LoginFailure('Improper token has been passed.') from exc
             raise
 
@@ -597,7 +604,7 @@ class HTTPClient:
             emoji=emoji,
         )
 
-        params = {
+        params: Dict[str, Any] = {
             'limit': limit,
         }
         if after: