AsyncThrottler missing pair-specific rate limits for dynamically registered trading pairs (AttributeError: 'NoneType' object has no attribute 'weight')

[fengtality]

Summary

Trading connectors are created with trading_pairs=[], so the connector's AsyncThrottler builds its rate limits from an empty pair list at init. When a trading pair is later registered dynamically (appended to connector._trading_pairs), the throttler is never updated. Any pair-specific limit_id (e.g. Bybit's v5/position/set-leverage-{PAIR}, v5/order/create-{PAIR}) then resolves to None, and the client crashes with:

AttributeError: 'NoneType' object has no attribute 'weight'

Reported by a community user on Discord (bybit_perpetual, Ubuntu, clean install, one-server mode); root cause verified against the code.

Root cause

• UnifiedConnectorService._create_trading_connector() builds connectors with trading_pairs=[] (services/unified_connector_service.py:695, same for Gateway at :687 and data connectors at :725).
• For connectors with pair-specific rate limits, e.g. bybit_perpetual:

  @property
  def rate_limits_rules(self) -> List[RateLimit]:
      return web_utils.build_rate_limits(self.trading_pairs)

  The AsyncThrottler is constructed once from this list during connector init — with no pairs, so no pair-specific limits exist.
• Pairs added later via connector._trading_pairs.append(...) never reach the throttler, so throttler.execute_task(limit_id=...) finds no matching rate limit for pair-scoped endpoints.

Note: reassigning connector._throttler = AsyncThrottler(new_limits) does not fix it — WebAssistantsFactory captures the original throttler reference at connector init, so the new object is never used by the REST/WS assistants.

Symptoms

• POST to set position mode / leverage returns 500: 'NoneType' object has no attribute 'weight'
• Order placement via executors silently retries and fails (Open order failed... Retrying N/10) — the order never reaches the exchange and no useful error surfaces.

Affected connectors

Any connector whose rate limits are built per trading pair (e.g. bybit_perpetual; other connectors with {PAIR}-templated limit IDs are likely affected the same way).

Suggested fix

When a trading pair is registered on a connector, sync the existing throttler in place using AsyncThrottler.add_rate_limits(connector.rate_limits_rules). This mutates the throttler object the WebAssistantsFactory already holds, and it is idempotent — safe to call unconditionally on every pair registration rather than only for unseen pairs (a pair can also land in _trading_pairs via the data-connector bootstrap path without going through the registration helper).

The reporter confirmed this fix end-to-end on two pairs after a container rebuild: BUY/SELL executed on first attempt (current_retries: 0), and position close was confirmed by the exchange.