[nissa-seru]

On top of #916, entering a channel's tune-out while an older all-except hold is in force now leaves the subconscious's window anchor at the hold's start, and docs/dendrite.md's tune-out paragraph says when the coordinator exists and what a restart resumes. In this pull request's new test, a hold entered at sequence 3 and then a channel's tune-out entered at 20 give the anchors [3, 20] with #916's coordinator at 9704133265, and [3, 3] at this head. main's coordinator at 48f26ce56c gives [3, 20] too.

@tel-0s, this pull request goes into #916's branch, fix/tune-out-resume-late-channels, and adds two commits to it. We're asking you to merge it there, so the anchor fix and the paragraph land with #916's fix.

Problem

At 9704133265, enter() sets the subconscious's window anchor with these lines (src/tune-out/coordinator.ts:678–682):

const oldest = this.listActive().reduce(
  (min, e) => Math.min(min, e.params.startedAtSequence),
  params.startedAtSequence,
);
this.hooks.setSubconsciousAnchor(oldest);

With #916's coordinator in place of this head's, the new test, "a tune-out entered while an older all-except hold is in force leaves the subconscious's window start at the hold's start", fails at its last assertion: the anchors are [3, 20] where [3, 3] was expected. The hold's start is 3, and the second anchor is the new tune-out's start, 20.

Changes

• enter()'s reduce (src/tune-out/coordinator.ts:678–681) starts from scope ? Math.min(params.startedAtSequence, scope.params.startedAtSequence) : params.startedAtSequence, where scope is this.getAllExcept(), which enter() already reads (:649). The comment above it now reads "Never move the anchor past the start of an epoch still in force, a tune-out's or the all-except hold's."
• test/tune-out-resume-late-channels.test.ts gains that test, over the real ChannelRegistry and a JsStore. Its coordinatorOn takes what the coordinator's currentSequence hook answers as an optional fourth argument, whose default is the () => 9 the hook had.
• docs/dendrite.md's "Tune-out without a reader" paragraph (:278), in a commit of its own, e2dc0af961, on top of the fix in 65e58aa35a, so it can be dropped whole. Beyond the sentence for fix(tune-out): resume a tune-out on record whose channel isn't registered at the start #916's own change, "A restart resumes every tune-out on record, …", it replaces two sentences that main's own tests contradict. At a clean 48f26ce56c, "a tune-out on record at a start with no subconscious ends there, …" and "a tune-out on record when a start without servers connects one later ends then, …" (test/tune-out-transport.test.ts:1419 and :1448) pass (Tests). In each, MCPL comes up with a tune-out on record, the tune-out ends, and the log line the test asserts says "nothing on this host watches or cancels tune-outs". The paragraph's changes:
  • "The tune-out coordinator exists whenever MCPL channels do." becomes "The tune-out coordinator exists when create() brings up MCPL channels and a reader is configured or tuneOut.enabled is set, and residents are offered tune_out only where it exists."
  • "A persisted epoch is therefore always resumed and released, whatever the configuration (gap 10)." becomes "Where the coordinator exists, a persisted epoch is resumed, and released when it ends, with a reader or without one (gap 10)."
  • Two sentences are added: "A restart resumes every tune-out on record, whether or not its channel is registered yet, since a host's servers may register their channels after create() returns (#900)." and "Where there is no coordinator, as where no reader is configured and tuneOut.enabled isn't set, or where MCPL first comes up after create() with connectMcplServer(), each channel's tune-out on record ends when MCPL comes up, and nothing delivers its backlog."
  • The paragraph's last sentence before this change, "Residents are offered tune_out when a reader is configured or tuneOut.enabled is set.", is cut, and the new first sentence says where residents are offered tune_out.
• changelog.d/tune-out-anchor-hold-in-force.fixed.md: "Hosts with a subconscious: entering a channel's tune-out while an older all-except hold is in force no longer moves the subconscious's window anchor past the hold's start."

With #844

@tel-0s, #844 (c7011d5c7a) merges with #916's head with no conflicts, by git merge-tree on October 30 at 08:08 UTC. With this head in place of #916's, it conflicts in src/tune-out/coordinator.ts, in one block: enter()'s window anchor, where #844 calls anchorSubconscious() and this head has the reduce under Changes. Each of the other 39 pull requests open then merges with this head as it does with #916's.

Tests

At a clean checkout of e2dc0af961, on Linux with Node 24.22.2 and npm 11.19.1, after npm install with package-lock.json and node_modules removed. npm ls --depth=0 gives @animalabs/chronicle 0.5.1, @animalabs/context-manager 0.24.1, @animalabs/mcpl-core 0.4.0, @animalabs/membrane 0.8.0, @babel/parser 7.29.12, @modelcontextprotocol/client 2.4.0, @modelcontextprotocol/server 2.4.0, @types/node 22.20.5, @types/ws 8.18.2, chokidar 4.0.3, discord.js 14.27.0, tsx 4.23.15, typescript 7.0.2 and ws 8.22.0. npx tsc --noEmit, npm run build and npm run pretest each exited 0. Each test file ran alone, with the flags npm test gives node and the TAP reporter:

• The 46 test files whose source names TuneOutCoordinator, tune_out, tuneOut, cancelTuneOut or all-except: 1,106 of 1,106 tests pass, among them tune-out-resume-late-channels's 4.
• With fix(tune-out): resume a tune-out on record whose channel isn't registered at the start #916's src/tune-out/coordinator.ts (9704133265) built in place of this head's: tune-out-resume-late-channels passes 3 and fails 1, the new test, at its last assertion, with [3, 20] where [3, 3] was expected.
• With main's src/tune-out/coordinator.ts (48f26ce56c) built in its place: all 4 fail, fix(tune-out): resume a tune-out on record whose channel isn't registered at the start #916's three and the new test, which fails at the same assertion with [3, 20].

At a clean checkout of main at 48f26ce56c, set up the same way, with the same versions, npm run build and npm run pretest each exited 0, and test/tune-out-transport.test.ts, which this pull request and #916 leave as main has it, passes 60 of 60.

Not verified

• Platforms other than Linux, and this repository's CI, which hasn't run this change.
• The rest of the suite. We ran the 46 test files Tests names, of the 391 in test/.
• The subconscious's window. The test asserts the sequences the coordinator passes to setSubconsciousAnchor, not what the window then holds.
• The paragraph's account of when the coordinator exists, and of a host without one. No run here started a framework, with a coordinator or without one.

---

• Changelog fragment added: changelog.d/tune-out-anchor-hold-in-force.fixed.md.

Hilda-2681 made this change and ran it red first. The anchor fix and the paragraph first went into an earlier change of ours for #900, which Crispin-2406 read. Naomi-2422 read this pull request. Fern-2426 ran our internal review of #916. Daniel-2612 repeated the runs at a clean checkout and wrote this description.