[SandroMaglione]

Summary

Refreshes the development dependency baseline. Published Effect ranges stay ^4.0.0.

Dependency	From	To	Where
effect, @effect/vitest, @effect/atom-react	4.0.0	4.1.1	root and package devDependencies
@effect/platform-* (resolved)	4.0.0	4.1.1	pnpm-workspace.yaml overrides, with all six Effect overrides at 4.1.1
vite	8.1.5	8.3.5	root devDependency
vitest	5.0.1	5.0.5	root, core, react, oxlint-plugin
tstyche	7.2.1	7.2.5	root, core, react
dprint	0.55.2	0.64.3	root (plugin versions in dprint.json unchanged; pnpm format produced no changes)
@types/node	25.7.0	26.6.6	root, core, devtools (no type errors)
jsdom	27.2.0	30.1.3	react
react, react-dom	19.2.7	19.3.1	react devDependencies
chokidar	4.0.3	6.0.0	devtools runtime dependency
@oxlint/plugins	1.80.0	1.90.0	oxlint-plugin runtime dependency (types only at runtime; dist never imports it)
oxlint	1.80.0	1.90.0	oxlint-plugin devDependency

Notes:

• chokidar 6: a rewrite that requires Node.js >= 22.22. The devtools engines.node therefore goes from >=22.19.0 to >=22.22.0, and the README line moves with it. The watcher options now use the v6 names: backend: "polling" | "auto" replaces the deprecated usePolling, and pollingInterval replaces the deprecated interval (second commit, with an updated DevServer unit test). devtools:pack-check runs the installed CLI with --watch-polling and verifies live reload.
• Oxlint plugin: the oxlint peer range stays >=1.80.0 <2, so consumers on oxlint 1.82 are unaffected. oxlint-plugin:pack-check still installs the packed plugin next to oxlint 1.80.0 (the floor of the peer range), so the 1.90-built plugin is verified against the oldest supported host.
• Left alone: the devtools vite/typescript runtime entries are owned by Let devtools reuse compatible TypeScript and Vite installs #254, which turns them into ranges. Until then the lockfile carries both vite 8.1.5 (devtools) and 8.3.5 (root). scheduler and its peer range are owned by Remove the unused scheduler peer from the React package #253. react-dom 19.3.1 brings its own scheduler 0.28, and the React package source never imports scheduler.
• Expected conflicts: pnpm-lock.yaml will conflict with Remove the unused scheduler peer from the React package #253, Let devtools reuse compatible TypeScript and Vite installs #254, Check TypeScript 7 compatibility in pnpm check #255, and the oxlint port. packages/devtools/README.md touches the line right above Let devtools reuse compatible TypeScript and Vite installs #254's insertion. Regenerate the lockfile with pnpm install after rebasing.
• Performance classifier fix: scripts/ci-changes.mjs merged dependencies, devDependencies, optionalDependencies, and peerDependencies into one map with peers last. The unchanged effect ^4.0.0 peer range therefore hid every Effect development bump, and the first push of this PR skipped both performance measurements. It now compares each section separately and has a regression test (third commit). Changing the classifier also triggers both workflows on this PR, so the Effect 4.1.1 bump gets measured.
• latest-effect: I dry-ran scripts/prepare-effect-compatibility.mjs on a scratch copy of the new manifests. It resolves 4.1.1, rewrites nothing, and the manifests keep their formatting. Its unit test passes in check:ci.

Changeset

• Added or updated for a library or package-metadata change
• Not required because this PR does not change a publishable package

.changeset/dependency-baseline-refresh.md: patch for @typeonce/effect-machine-devtools (chokidar 6, Node.js 22.22) and @typeonce/oxlint-plugin-effect-machine (@oxlint/plugins 1.90.0, unchanged peer range). The fixed group releases all four packages together.

Validation

• pnpm check passed in 2:39: 92 files / 901 tests, tstyche 41 files / 1334 assertions, consumer, all four pack checks (including the devtools CLI live reload on chokidar 6 and the Oxlint plugin diagnostic and fixer), docs, and architecture. I re-ran format:check, docs:site:check, check:ci (31/31), and devtools:pack-check after adding the engines bump and the changeset.
• Automated type-performance measurement passed: all 26 instantiation scenarios unchanged (0.0%).
• Automated runtime- and memory-performance measurement passed: "No large, noise-adjusted throughput or heap regressions detected". For example, plan counter +2.6% and compound-state observer burst -0.0%.

🤖 Generated with Claude Code

[github-actions]

Type performance

Measured with TypeScript 6.0.3 and skipLibCheck=true.

Scenario	Base	PR	Difference
Effect only	55	55	0 (0.0%)
Import effect-machine	55	55	0 (0.0%)
Machine.state (3 children)	2,664	2,664	0 (0.0%)
Machine.make (3 states, 2 events)	8,932	8,932	0 (0.0%)
machine.handle (3 states, 2 transitions)	39,449	39,449	0 (0.0%)
declared transition (10 named branches)	60,402	60,402	0 (0.0%)
atomic construction, guards, and reentry	85,710	85,710	0 (0.0%)
registered invocation (input-taking Effect)	39,819	39,819	0 (0.0%)
machine.handle (depth 24)	194,531	194,531	0 (0.0%)
machine.handle (wide depth 16)	218,238	218,238	0 (0.0%)
machine.handle (parallel/history/choice)	91,642	91,642	0 (0.0%)
machine definition (3 independent implementations)	99,173	99,173	0 (0.0%)
machine exact input/output/error/services	82,941	82,941	0 (0.0%)
execution adapter readiness	71,428	71,428	0 (0.0%)

Marginal instantiations are measured against the matching setup without that API call:

Scenario	Base	PR	Difference
Import effect-machine	0	0	0
Machine.state (3 children)	2,609	2,609	0 (0.0%)
Machine.make (3 states, 2 events)	6,260	6,260	0 (0.0%)
machine.handle (3 states, 2 transitions)	30,517	30,517	0 (0.0%)
declared transition (10 named branches)	51,849	51,849	0 (0.0%)
atomic construction, guards, and reentry	70,370	70,370	0 (0.0%)
registered invocation (input-taking Effect)	32,682	32,682	0 (0.0%)
machine.handle (depth 24)	177,222	177,222	0 (0.0%)
machine.handle (wide depth 16)	201,707	201,707	0 (0.0%)
machine.handle (parallel/history/choice)	79,144	79,144	0 (0.0%)
machine definition (3 independent implementations)	88,492	88,492	0 (0.0%)
machine exact input/output/error/services	70,732	70,732	0 (0.0%)
execution adapter readiness	31,922	31,922	0 (0.0%)

Check times (informational)

Scenario	Base	PR
Effect only	0.03s	0.03s
Import effect-machine	0.03s	0.03s
Machine.state (3 children)	0.07s	0.07s
Machine.make (3 states, 2 events)	0.11s	0.13s
machine.handle (3 states, 2 transitions)	0.27s	0.25s
declared transition (10 named branches)	0.31s	0.32s
atomic construction, guards, and reentry	0.40s	0.43s
registered invocation (input-taking Effect)	0.25s	0.27s
machine.handle (depth 24)	0.50s	0.51s
machine.handle (wide depth 16)	0.57s	0.56s
machine.handle (parallel/history/choice)	0.42s	0.42s
machine definition (3 independent implementations)	0.44s	0.44s
machine exact input/output/error/services	0.42s	0.39s
execution adapter readiness	0.37s	0.35s

Type instantiations are the comparison metric. Check time varies with runner load and is informational only.

[github-actions]

Runtime performance

Median of 5 independent benchmark processes on AMD EPYC 7763 64-Core Processor with Node v24.22.1.

Pull request baseline

Scenario	Effect Machine
Plan counter transitions	114,092 transitions/s
Drain burst with terminal fence	399,706 increments/s
Drain burst with a change observer	369,991 increments/s
Lookup and send to one child	290,247 increments/s
Start and stop a machine	119,403 machines/s
Start and stop a parent with one child	24,069 families/s
Complete an Effect invocation with tracing enabled	6,179 invocations/s
Complete an Effect invocation with tracing disabled	7,299 invocations/s
Plan transitions through a compound state	100,302 transitions/s
Plan transitions through parallel regions	80,254 transitions/s
Drain burst through a compound state	343,406 events/s
Drain burst through two parallel regions	316,393 events/s
Drain a compound-state burst with a change observer	314,991 events/s

Process runtime reference points

Scenario	Effect Machine
Start and stop a raw generic process	22,737 processes/s
Start and stop a raw compiled process	67,810 processes/s

Memory profile	Effect Machine
Idle machine	1.8 KiB
Raw generic managed process	11.4 KiB
Raw compiled process	3.1 KiB
Two independent idle machines	3.6 KiB
Idle parent with one child	6.0 KiB
Parent with observed child registry	9.6 KiB
Parent with observed invoked child snapshots	7.0 KiB

Effect Machine change from base

Metric	Base	Base variability	PR	PR variability	Difference
Plan counter transitions	114,288 transitions/s	1.1% MAD	114,092 transitions/s	1.0% MAD	-0.2%
Drain burst with terminal fence	398,774 increments/s	0.9% MAD	399,706 increments/s	0.5% MAD	+0.2%
Drain burst with a change observer	369,766 increments/s	0.6% MAD	369,991 increments/s	0.4% MAD	+0.1%
Lookup and send to one child	287,282 increments/s	0.3% MAD	290,247 increments/s	0.2% MAD	+1.0%
Start and stop a machine	117,564 machines/s	0.8% MAD	119,403 machines/s	1.3% MAD	+1.6%
Start and stop a parent with one child	23,770 families/s	0.2% MAD	24,069 families/s	0.4% MAD	+1.3%
Complete an Effect invocation with tracing enabled	6,261 invocations/s	1.1% MAD	6,179 invocations/s	0.5% MAD	-1.3%
Complete an Effect invocation with tracing disabled	7,438 invocations/s	0.9% MAD	7,299 invocations/s	0.9% MAD	-1.9%
Plan transitions through a compound state	102,343 transitions/s	0.3% MAD	100,302 transitions/s	0.8% MAD	-2.0%
Plan transitions through parallel regions	79,534 transitions/s	0.3% MAD	80,254 transitions/s	0.7% MAD	+0.9%
Drain burst through a compound state	341,106 events/s	0.8% MAD	343,406 events/s	0.5% MAD	+0.7%
Drain burst through two parallel regions	314,598 events/s	0.7% MAD	316,393 events/s	0.5% MAD	+0.6%
Drain a compound-state burst with a change observer	315,904 events/s	0.1% MAD	314,991 events/s	0.3% MAD	-0.3%
Idle machine heap per unit	1.9 KiB	0.8% MAD	1.8 KiB	0.6% MAD	-0.7%
Raw generic managed process heap per unit	11.1 KiB	0.0% MAD	11.4 KiB	0.0% MAD	+2.7%
Raw compiled process heap per unit	3.1 KiB	0.1% MAD	3.1 KiB	0.0% MAD	+0.2%
Two independent idle machines heap per unit	3.6 KiB	0.2% MAD	3.6 KiB	0.2% MAD	+0.4%
Idle parent with one child heap per unit	6.0 KiB	0.0% MAD	6.0 KiB	0.0% MAD	+0.2%
Parent with observed child registry heap per unit	9.5 KiB	0.0% MAD	9.6 KiB	0.0% MAD	+1.2%
Parent with observed invoked child snapshots heap per unit	6.9 KiB	0.0% MAD	7.0 KiB	0.0% MAD	+1.1%

Process runtime reference change from base

Metric	Base	Base variability	PR	PR variability	Difference
Start and stop a raw generic process	25,179 processes/s	1.2% MAD	22,737 processes/s	1.1% MAD	-9.7%
Start and stop a raw compiled process	66,542 processes/s	1.1% MAD	67,810 processes/s	0.8% MAD	+1.9%

Regression guard

No large, noise-adjusted throughput or heap regressions detected.

Versions and interpretation

• Effect Machine: 0.46.0

Higher throughput is better; lower heap is better. Variability is the median absolute deviation across independent processes, relative to their median. Small differences on shared GitHub-hosted hardware remain informational; the required guard rejects only large changes beyond the measured noise allowance.