Prefer `type(x) is int` to `isinstance(x, int)` (#14945)

* Perfer `type(x) is int` to `isinstance(x, int)`

This covered all additional instances I could see where `x` was
user-controlled.
The remaining cases are

```
$ rg -s 'isinstance.*[^_]int'
tests/replication/_base.py
576:        if isinstance(obj, int):

synapse/util/caches/stream_change_cache.py
136:        assert isinstance(stream_pos, int)
214:        assert isinstance(stream_pos, int)
246:        assert isinstance(stream_pos, int)
267:        assert isinstance(stream_pos, int)

synapse/replication/tcp/external_cache.py
133:        if isinstance(result, int):

synapse/metrics/__init__.py
100:        if isinstance(calls, (int, float)):

synapse/handlers/appservice.py
262:        assert isinstance(new_token, int)

synapse/config/_util.py
62:        if isinstance(p, int):
```

which cover metrics, logic related to `jsonschema`, and replication and
data streams. AFAICS these are all internal to Synapse

* Changelog

3 files changed, 11 insertions, 12 deletions

diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index fb73886df0..79f22a59f1 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -152,7 +152,7 @@ class PurgeHistoryRestServlet(RestServlet):
             logger.info("[purge] purging up to token %s (event_id %s)", token, event_id)
         elif "purge_up_to_ts" in body:
             ts = body["purge_up_to_ts"]
-            if not isinstance(ts, int):
+            if type(ts) is not int:
                 raise SynapseError(
                     HTTPStatus.BAD_REQUEST,
                     "purge_up_to_ts must be an int",
diff --git a/synapse/rest/admin/registration_tokens.py b/synapse/rest/admin/registration_tokens.py
index af606e9252..95e751288b 100644
--- a/synapse/rest/admin/registration_tokens.py
+++ b/synapse/rest/admin/registration_tokens.py
@@ -143,7 +143,7 @@ class NewRegistrationTokenRestServlet(RestServlet):
         else:
             # Get length of token to generate (default is 16)
             length = body.get("length", 16)
-            if not isinstance(length, int):
+            if type(length) is not int:
                 raise SynapseError(
                     HTTPStatus.BAD_REQUEST,
                     "length must be an integer",
@@ -163,8 +163,7 @@ class NewRegistrationTokenRestServlet(RestServlet):
 
         uses_allowed = body.get("uses_allowed", None)
         if not (
-            uses_allowed is None
-            or (isinstance(uses_allowed, int) and uses_allowed >= 0)
+            uses_allowed is None or (type(uses_allowed) is int and uses_allowed >= 0)
         ):
             raise SynapseError(
                 HTTPStatus.BAD_REQUEST,
@@ -173,13 +172,13 @@ class NewRegistrationTokenRestServlet(RestServlet):
             )
 
         expiry_time = body.get("expiry_time", None)
-        if not isinstance(expiry_time, (int, type(None))):
+        if type(expiry_time) not in (int, type(None)):
             raise SynapseError(
                 HTTPStatus.BAD_REQUEST,
                 "expiry_time must be an integer or null",
                 Codes.INVALID_PARAM,
             )
-        if isinstance(expiry_time, int) and expiry_time < self.clock.time_msec():
+        if type(expiry_time) is int and expiry_time < self.clock.time_msec():
             raise SynapseError(
                 HTTPStatus.BAD_REQUEST,
                 "expiry_time must not be in the past",
@@ -284,7 +283,7 @@ class RegistrationTokenRestServlet(RestServlet):
             uses_allowed = body["uses_allowed"]
             if not (
                 uses_allowed is None
-                or (isinstance(uses_allowed, int) and uses_allowed >= 0)
+                or (type(uses_allowed) is int and uses_allowed >= 0)
             ):
                 raise SynapseError(
                     HTTPStatus.BAD_REQUEST,
@@ -295,13 +294,13 @@ class RegistrationTokenRestServlet(RestServlet):
 
         if "expiry_time" in body:
             expiry_time = body["expiry_time"]
-            if not isinstance(expiry_time, (int, type(None))):
+            if type(expiry_time) not in (int, type(None)):
                 raise SynapseError(
                     HTTPStatus.BAD_REQUEST,
                     "expiry_time must be an integer or null",
                     Codes.INVALID_PARAM,
                 )
-            if isinstance(expiry_time, int) and expiry_time < self.clock.time_msec():
+            if type(expiry_time) is int and expiry_time < self.clock.time_msec():
                 raise SynapseError(
                     HTTPStatus.BAD_REQUEST,
                     "expiry_time must not be in the past",
diff --git a/synapse/rest/admin/users.py b/synapse/rest/admin/users.py
index 6e0c44be2a..0841b89c1a 100644
--- a/synapse/rest/admin/users.py
+++ b/synapse/rest/admin/users.py
@@ -973,7 +973,7 @@ class UserTokenRestServlet(RestServlet):
         body = parse_json_object_from_request(request, allow_empty_body=True)
 
         valid_until_ms = body.get("valid_until_ms")
-        if valid_until_ms and not isinstance(valid_until_ms, int):
+        if type(valid_until_ms) not in (int, type(None)):
             raise SynapseError(
                 HTTPStatus.BAD_REQUEST, "'valid_until_ms' parameter must be an int"
             )
@@ -1125,14 +1125,14 @@ class RateLimitRestServlet(RestServlet):
         messages_per_second = body.get("messages_per_second", 0)
         burst_count = body.get("burst_count", 0)
 
-        if not isinstance(messages_per_second, int) or messages_per_second < 0:
+        if type(messages_per_second) is not int or messages_per_second < 0:
             raise SynapseError(
                 HTTPStatus.BAD_REQUEST,
                 "%r parameter must be a positive int" % (messages_per_second,),
                 errcode=Codes.INVALID_PARAM,
             )
 
-        if not isinstance(burst_count, int) or burst_count < 0:
+        if type(burst_count) is not int or burst_count < 0:
             raise SynapseError(
                 HTTPStatus.BAD_REQUEST,
                 "%r parameter must be a positive int" % (burst_count,),