fix(discord): channel name matching and flush pending sends on shutdown

[Nickperillo]

Summary

Two bug fixes to the Discord gateway adapter discovered and patched in production use.

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Fix 1: Channel name matching for free-response, allowed, ignored, and no-thread channels

Problem: Config values like free_response_channels: cypher were silently ignored because the adapter only matched against numeric channel IDs (channel_ids set). If a user configured channel names or #name forms, none of the gates (is_free_channel, skip_thread, allowed/ignored checks) would trigger.

Fix: Build a channel_keys set alongside channel_ids that includes:

• the numeric channel ID (existing)
• the channel name string (new)
• the #channel-name form (new)
• same for parent channels in threads

All gate checks now use channel_keys for name-form matching and channel_ids for ID matching.

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Fix 2: Flush pending text-batch tasks before shutdown to prevent dropped messages

Problem: DiscordAdapter maintains its own _pending_text_batch_tasks dict for merging rapid successive Discord message chunks (the 2000-char split logic). These tasks were not added to self._background_tasks (the base class list). As a result, cancel_background_tasks() in the base class never awaited them on gateway restart or shutdown.

This created a race condition: on restart, the gateway would call cancel_background_tasks() then disconnect() (closing the Discord client) while in-flight response delivery tasks were still pending. The tasks would be killed by the event loop without completing, causing silent dropped messages — users saw only tool-log activity with no text response body.

Fix: Override cancel_background_tasks() in DiscordAdapter to await all pending _pending_text_batch_tasks (with an 8-second deadline) before delegating to super().cancel_background_tasks(). If the deadline is exceeded, remaining tasks are cancelled gracefully.

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Testing

Both fixes were validated in production on a Discord gateway instance running claude-sonnet-4-6 via Anthropic. The dropped-message race was reproducible on every gateway restart when a response was in-flight; after the fix, responses land correctly even through restarts.

[teknium1]

Merged via #55525 — your commit was cherry-picked onto current main with your authorship preserved in git log (commit cb9308f).

Both your fixes landed:

• Channel-name / #name matching across the on_message free-response, allowed, ignored, and no-thread gates.
• Flushing _pending_text_batch_tasks before shutdown so in-flight responses aren't dropped on gateway restart.

On top of your work we added: the same channel-name matching at the slash-command authorization gate (sibling site that still matched IDs only), and a clamp so the flush deadline derives from the gateway's per-adapter disconnect budget instead of a fixed 8s (the outer wait_for could otherwise hard-cancel the flush mid-send).

Thanks for the fix and the clear writeup!