fix(matrix-bridge): enforce strict one-emoji invariant

[replicas-connector]

Summary

Per Jaden's "Just one" directive on the Slack thread — closes two cases where the per-prompt redact-before-react flow was leaking orphaned 👀s across a steered conversation.

Before: Each prompt's reaction was correct on the happy path, but across a steered turn (Prompt A still in flight when Prompt B lands) Prompt A's 👀 was orphaned forever, and a late /ack arriving after terminal would stack a stale 👀 against the existing 🎉.

After: Strict one-emoji-at-a-time across the whole conversation. Each prompt converges to exactly one reaction.

Fixes

Break 2 — Steered follow-ups (poller.ts:187 area)

The steering branch of /watch overwrote DO storage's reactionEventId with the new prompt's 👀 without redacting the prior. Now: before overwriting, fire-and-forget redact the prior reactionEventId if it differs from the incoming one. A failed redact logs but doesn't break steering.

Break 3 — Late /ack after terminal

Dispatch fires 👀 in parallel with watcher spawn, posting the id to the DO via /ack asynchronously. If terminal lands first, the swap runs with no prior to redact (placing just 🎉), then the late /ack arrives and the old handler dumbly stored its 👀 id — orphan stacking against the 🎉.

Now: on /ack entry, check phase. If DONE/FAILED, redact the incoming ackReactionId immediately instead of storing it. The swap already happened; there's no future swap to clean it up.

Break 1 (out of scope, accepted)

The redact ultimately failing after 4 × 429 retries remains the residual edge case. Adding a sweep-on-cleanup retry loop would expand scope; opening a follow-up issue if it shows up in practice.

Test plan

• bun run typecheck clean
• bun test src/render.test.ts — 43/43 pass
• Deployed to matrix bridge (version 176abf80)
• Live test: send Prompt A → mid-turn send Prompt B → verify A's 👀 disappears when B's status frame transitions to active
• Live test: trigger a slow /ack after a fast terminal (e.g., text-only turn under rate limit) and verify no stale 👀 stacks against the 🎉

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_{Created by Jaden (jadengarza@pm.me) with Replicas
Workspace  ·  Slack Thread}

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[devin-ai-integration]

Devin Review found 1 potential issue.

View 3 additional findings in Devin Review.

[devin-ai-integration]

🟡 Steering-path prior-👀 redact is dead code; the fix belongs in the /ack handler

The new redact logic at poller.ts:210-217 checks if (body.ackReactionId) inside the /watch steering path, but dispatch.ts never passes ackReactionId in the /watch call — both call sites (dispatch.ts:79 and dispatch.ts:105) pass undefined for that parameter. The ackReactionId always arrives later via the separate /ack endpoint (dispatch.ts:116-126). This means the steering-path redact code is unreachable, and the "orphaned 👀 on old prompt" bug the PR's comment describes is not actually fixed.

The /ack handler's non-terminal branch (poller.ts:127) simply overwrites reactionEventId without checking for or redacting the prior value, so during a steering follow-up the old prompt's 👀 is silently orphaned. The prior-reaction redact logic needs to live in the /ack handler's else branch, where watch is already available in scope.

Suggested change

	} else {
	writes.reactionEventId = body.ackReactionId;
	}
	} else {
	const priorReactionId = await this.state.storage.get<string>("reactionEventId");
	if (priorReactionId && priorReactionId !== body.ackReactionId && watch?.roomId) {
	redact(matrixEnv(this.env), watch.roomId, priorReactionId, "ack: replaced prior 👀")
	.catch((e) => console.log(`[poller] /ack redact prior 👀 failed: ${e instanceof Error ? e.message : e}`));
	}
	writes.reactionEventId = body.ackReactionId;
	}

---

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[replicas-connector]

🟡 Steering-path prior-👀 redact is dead code; the fix belongs in the /ack handler

The new redact logic at poller.ts:210-217 checks if (body.ackReactionId) inside the /watch steering path, but dispatch.ts never passes ackReactionId in the /watch call — both call sites (dispatch.ts:79 and dispatch.ts:105) pass undefined for that parameter. The ackReactionId always arrives later via the separate /ack endpoint (dispatch.ts:116-126). This means the steering-path redact code is unreachable, and the "orphaned 👀 on old prompt" bug the PR's comment describes is not actually fixed.

The /ack handler's non-terminal branch (poller.ts:127) simply overwrites reactionEventId without checking for or redacting the prior value, so during a steering follow-up the old prompt's 👀 is silently orphaned. The prior-reaction redact logic needs to live in the /ack handler's else branch, where watch is already available in scope.

Suggested change

	} else {
	writes.reactionEventId = body.ackReactionId;
	}
	} else {
	const priorReactionId = await this.state.storage.get<string>("reactionEventId");
	if (priorReactionId && priorReactionId !== body.ackReactionId && watch?.roomId) {
	redact(matrixEnv(this.env), watch.roomId, priorReactionId, "ack: replaced prior 👀")
	.catch((e) => console.log(`[poller] /ack redact prior 👀 failed: ${e instanceof Error ? e.message : e}`));
	}
	writes.reactionEventId = body.ackReactionId;
	}

---

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[replicas-connector]

Devin Review found 1 potential issue.

View 3 additional findings in Devin Review.

@devin-ai-integration[bot] This repository is not connected to a Replicas organization.

To enable Replicas on this repository:

1. Go to GitHub integration settings
2. Add this repository to your organization

Note: Each repository can only be connected to one Replicas organization.