PROD-58888: support jarvis-emitter v3 (meaco 2.0.0) by greg3d · Pull Request #1 · mceSystems/meaco

greg3d · 2026-05-17T10:20:38Z

Summary

Major bump: meaco 1.0.3 → 2.0.0.
dependencies."jarvis-emitter" ^2.0.4 → ^3.0.2 (caret — future 3.x picked up automatically).
Add a duck-type fallback in the JarvisEmitter detection branch in index.js so coroutines correctly await JarvisEmitter subclasses (e.g. gen2's NPPHandler) and tolerate cases where two jarvis-emitter copies coexist in the resolved tree (instanceof fails across duplicate class identities).
Guard the detection branch against null-prototype yields (Object.create(null)).
Add three regression specs covering the duck-type fallback and the null-prototype guard.

Why a major bump

Bumping jarvis-emitter from ^2.0.4 to ^3.0.2 is a transitive major upgrade. Per semver it can't ride a meaco minor — every meaco@^1 consumer would silently get a different jarvis-emitter major on their next install. So this PR releases as meaco@2.0.0.

In the mceSystems ecosystem this is also the honest framing: every internal consumer (mce/gen3, mce-2nd-gen/gen2, libijs, mce-aura-agent) is migrating to jarvis-emitter@3 in lockstep with this release.

Context — PROD-58888

The gen3 framework was upgraded to jarvis-emitter@3.0.2 while meaco@1.0.4 still pinned "jarvis-emitter": "^2.0.4". npm couldn't satisfy meaco's range from the hoisted v3 and nested a separate v2 copy under meaco/node_modules/jarvis-emitter. Two JarvisEmitter class objects coexisted at runtime; instanceof JarvisEmitter returned false for v3 instances created elsewhere (e.g. gen2's NPPHandler extends JarvisEmitter) → meaco's detection at index.js:37 fell through → yielded NPPHandler returned unresolved → device sessions closed ~1 s after connect.

Two complementary fixes in this PR:

Range — moving meaco to ^3.0.2 lets npm satisfy meaco's range from the framework's hoisted v3, so no nested duplicate is created.
Defensive — the duck-type fallback (typeof promise.done === "function" && typeof promise.callDone === "function") keeps meaco robust if a future major mismatch slips through (e.g. a JarvisEmitter subclass with a different constructor.name). The null-prototype guard prevents TypeError on Object.create(null) yields.

Merge / release order

This PR is #1 of 5 across repos for PROD-58888:

meaco ← this PR
publish meaco@2.0.0 to npm
mce (gen3) PR — bumps meaco to ^2.0.0
libijs PR + mce-aura-agent PR
mce-2nd-gen PR — bumps jarvis-emitter + meaco (regenerate lockfiles at install time against published meaco@2.0.0)

Test plan

npm test — 9/9 mocha specs pass (6 original + 3 new for duck-type detection and null-proto guard)
Clean npm install resolves a single jarvis-emitter@3.0.2
Smoke against framework once published

Bump jarvis-emitter peer to ^3.0.2 and bump meaco to 1.1.0. Add a duck-type fallback in the JarvisEmitter detection branch in index.js so coroutines correctly await JarvisEmitter subclasses (e.g. NPPHandler) and tolerate cases where two jarvis-emitter copies coexist in the resolved module tree — `instanceof JarvisEmitter` returns false across duplicate copies because the class identities differ. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Copilot

Pull request overview

Updates meaco to support jarvis-emitter@3.x and improves coroutine yield detection so JarvisEmitter-like objects (including subclasses and scenarios with duplicate installed copies) are awaited correctly.

Changes:

Bump meaco version to 1.1.0 and update jarvis-emitter dependency range to ^3.0.2.
Extend the JarvisEmitter detection branch in index.js with a duck-typing fallback (done/callDone).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
package.json	Version bump + widen `jarvis-emitter` dependency range to v3.
index.js	Add duck-typed JarvisEmitter detection to handle subclasses / duplicate installs.

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Address PR review: - Guard the JarvisEmitter detection branch with `typeof promise === "object" && promise.constructor` before reading `.constructor.name`, so a null-prototype yield (e.g. Object.create(null)) falls through to callDone instead of throwing TypeError. - Add three mocha specs covering the duck-type fallback that this PR introduced: 1. Yielding an emitter-like object that fails both `instanceof JarvisEmitter` and `constructor.name === "JarvisEmitter"` — the gen2/NPPHandler scenario where two jarvis-emitter copies coexist. 2. Error path on the same emitter-like object — verifies the error registerer is wired up correctly on duck-typed objects. 3. Null-prototype yield falls through cleanly to callDone instead of crashing the coroutine runner. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Per PR review, the packaging intent is that consumers provide the JarvisEmitter implementation — meaco both returns JarvisEmitter instances and checks `instanceof JarvisEmitter` against the consumer's copy. Listing it as a regular dependency invited nested duplicate copies (the root cause of PROD-58888 itself: meaco@1.0.4's "jarvis-emitter": "^2.0.4" forced a nested v2 alongside the framework's hoisted v3). Move to peerDependencies (npm 7+ enforces a single shared copy across the tree) and add to devDependencies so the mocha suite can install its own copy for local testing. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Copilot

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

Keep jarvis-emitter under dependencies — matches meaco@1.0.x packaging and is invisible to existing consumers (who all declare jarvis-emitter directly anyway). Peer-dep semantics would risk install-time warnings/regressions on older npm without adding meaningful protection, since the duck-type fallback added in this PR already handles the duplicate-class-identity case at runtime. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

nirhen

Semver concern on the version bump — see inline comment on package.json.

Per review (nirhen): bumping the range from ^2.0.4 to ^3.0.2 under a meaco minor bump (1.0.3 -> 1.1.0) silently forces every meaco@^1 consumer onto a transitive major upgrade. Per semver this would require meaco@2.0.0. The duck-type fallback added in this PR already handles both v2 and v3 emitter shapes at runtime (.done/.error/.catch/.callDone are unchanged across majors). Accepting both ranges lets npm dedupe to whatever the consumer's tree already has, avoiding the two-copies-in-tree scenario this PR was written to fix for one caller — and not reproducing it for every other consumer who happens to be on v2. Verified by running the mocha suite (9/9) against both jarvis-emitter@2.1.4 and @3.0.2. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Per review (nirhen): widening the jarvis-emitter range under a minor bump silently forces a transitive major upgrade on every meaco@^1 consumer. The correct semver move is to release this as meaco@2.0.0 with jarvis-emitter pinned to ^3.0.2 (caret — future 3.x patches and minors are picked up automatically without further meaco bumps). In the mceSystems ecosystem this is also the more honest call: every internal consumer (mce/gen3, mce-2nd-gen/gen2, libijs, mce-aura-agent) is migrating to jarvis-emitter@3 in lockstep with this release. No consumer is staying on v2, so the OR-range was hedging against a population that doesn't exist here. The duck-type fallback and null-prototype guard added earlier in this PR remain — they protect against subclass detection (e.g. NPPHandler) and any future duplicate-copy scenario regardless of version pin. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

Copilot AI review requested due to automatic review settings May 17, 2026 10:20

Copilot started reviewing on behalf of greg3d May 17, 2026 10:21 View session

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greg3d mentioned this pull request May 17, 2026

PROD-58888: bump jarvis-emitter ^1→^3.0.2 and meaco ^1.0→^1.1.0 mceSystems/libijs#10

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greg3d and others added 2 commits May 17, 2026 13:32

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greg3d and others added 2 commits May 17, 2026 13:42

Potential fix for pull request finding

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greg3d requested a review from Copilot May 17, 2026 10:44

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greg3d and others added 2 commits May 17, 2026 17:23

greg3d changed the title ~~PROD-58888: support jarvis-emitter v3 (meaco 1.1.0)~~ PROD-58888: support jarvis-emitter v3 (meaco 2.0.0) May 17, 2026

greg3d requested review from Copilot and nirhen May 17, 2026 14:45

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erezmce approved these changes May 17, 2026

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erezmce merged commit 0fdaf1c into master May 17, 2026
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PROD-58888: support jarvis-emitter v3 (meaco 2.0.0) - #1

PROD-58888: support jarvis-emitter v3 (meaco 2.0.0)#1
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PROD-58888-jarvis-emitter-v3-support

greg3d commented May 17, 2026 •

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greg3d commented May 17, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Why a major bump

Context — PROD-58888

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greg3d commented May 17, 2026 •

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