Upgrade Effect to rc.111

[SandroMaglione]

Summary

• Upgrade the exact effect peer and development dependency to 4.0.0-rc.111.
• Keep @effect/vitest, @effect/atom-react, examples, workspace overrides, and lockfiles aligned on rc.111.
• Update the installation guidance and add a patch changeset.

Changeset

• Added or updated for a library or package-metadata change
• Not required because this PR does not change src/ or package.json

Validation

• pnpm check
• Relevant example checks, when examples changed
• Automated type-performance measurement passed or was not required
• Automated runtime- and memory-performance measurement passed or was not required

Local validation:

• pnpm check
• pnpm check in examples/platformer
• pnpm check in examples/playground
• pnpm check in examples/pokemon
• pnpm perf:types
• pnpm perf:runtime

The CI base-versus-PR comparisons remain authoritative for performance.

[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.states (3 states)	3,039	3,039	0 (0.0%)
Machine.make (3 states, 2 events)	10,759	10,759	0 (0.0%)
machine.handle (3 states, 2 transitions)	28,192	28,192	0 (0.0%)
fluent transition (10 named branches)	106,006	106,006	0 (0.0%)
fluent invocation (state-dependent Effect)	92,756	92,756	0 (0.0%)
machine.handle (depth 24)	192,588	192,588	0 (0.0%)
machine.handle (wide depth 16)	220,950	220,950	0 (0.0%)
machine.handle (parallel/history/choice)	128,393	128,393	0 (0.0%)
machine definition (3 independent implementations)	127,346	127,346	0 (0.0%)
machine exact input/output/error/services	113,924	113,924	0 (0.0%)
execution adapter readiness	120,586	120,586	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.states (3 states)	2,984	2,984	0 (0.0%)
Machine.make (3 states, 2 events)	7,712	7,712	0 (0.0%)
machine.handle (3 states, 2 transitions)	17,433	17,433	0 (0.0%)
fluent transition (10 named branches)	95,757	95,757	0 (0.0%)
fluent invocation (state-dependent Effect)	83,491	83,491	0 (0.0%)
machine.handle (depth 24)	171,892	171,892	0 (0.0%)
machine.handle (wide depth 16)	201,461	201,461	0 (0.0%)
machine.handle (parallel/history/choice)	108,130	108,130	0 (0.0%)
machine definition (3 independent implementations)	111,377	111,377	0 (0.0%)
machine exact input/output/error/services	99,413	99,413	0 (0.0%)
execution adapter readiness	90,770	90,770	0 (0.0%)

Check times (informational)

Scenario	Base	PR
Effect only	0.03s	0.05s
Import effect-machine	0.03s	0.03s
Machine.states (3 states)	0.10s	0.10s
Machine.make (3 states, 2 events)	0.17s	0.18s
machine.handle (3 states, 2 transitions)	0.27s	0.28s
fluent transition (10 named branches)	0.52s	0.52s
fluent invocation (state-dependent Effect)	0.50s	0.52s
machine.handle (depth 24)	0.81s	0.81s
machine.handle (wide depth 16)	0.83s	0.83s
machine.handle (parallel/history/choice)	0.64s	0.68s
machine definition (3 independent implementations)	0.65s	0.64s
machine exact input/output/error/services	0.61s	0.60s
execution adapter readiness	0.59s	0.60s

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 v24.19.0.

Pull request baseline

Scenario	Effect Machine
Plan counter transitions	117,813 transitions/s
Drain burst with terminal fence	355,442 increments/s
Drain burst with a change observer	330,470 increments/s
Lookup and send to one child	294,267 increments/s
Start and stop a machine	142,167 machines/s
Start and stop a parent with one child	28,276 families/s
Plan transitions through a compound state	100,056 transitions/s
Plan transitions through parallel regions	82,015 transitions/s
Drain burst through a compound state	302,158 events/s
Drain burst through two parallel regions	303,220 events/s
Drain a compound-state burst with a change observer	283,738 events/s

Process runtime reference points

Scenario	Effect Machine
Start and stop a raw generic process	15,420 processes/s
Start and stop a raw compiled process	62,267 processes/s

Memory profile	Effect Machine
Idle machine	1.8 KiB
Raw generic managed process	13.9 KiB
Raw compiled process	3.1 KiB
Two independent idle machines	3.4 KiB
Idle parent with one child	5.8 KiB
Parent with observed child registry	10.0 KiB
Parent with observed invoked child snapshots	6.3 KiB

Effect Machine change from base

Metric	Base	Base variability	PR	PR variability	Difference
Plan counter transitions	117,189 transitions/s	0.5% MAD	117,813 transitions/s	0.6% MAD	+0.5%
Drain burst with terminal fence	354,232 increments/s	0.4% MAD	355,442 increments/s	1.0% MAD	+0.3%
Drain burst with a change observer	333,522 increments/s	0.9% MAD	330,470 increments/s	1.1% MAD	-0.9%
Lookup and send to one child	293,722 increments/s	0.5% MAD	294,267 increments/s	0.5% MAD	+0.2%
Start and stop a machine	142,389 machines/s	2.2% MAD	142,167 machines/s	0.8% MAD	-0.2%
Start and stop a parent with one child	28,404 families/s	0.7% MAD	28,276 families/s	1.7% MAD	-0.5%
Plan transitions through a compound state	101,115 transitions/s	1.3% MAD	100,056 transitions/s	0.9% MAD	-1.0%
Plan transitions through parallel regions	82,281 transitions/s	0.8% MAD	82,015 transitions/s	1.4% MAD	-0.3%
Drain burst through a compound state	306,802 events/s	0.3% MAD	302,158 events/s	1.6% MAD	-1.5%
Drain burst through two parallel regions	307,701 events/s	0.4% MAD	303,220 events/s	0.7% MAD	-1.5%
Drain a compound-state burst with a change observer	286,225 events/s	0.3% MAD	283,738 events/s	1.3% MAD	-0.9%
Idle machine heap per unit	1.8 KiB	0.2% MAD	1.8 KiB	0.0% MAD	0.0%
Raw generic managed process heap per unit	13.9 KiB	0.0% MAD	13.9 KiB	0.0% MAD	-0.0%
Raw compiled process heap per unit	3.2 KiB	0.4% MAD	3.1 KiB	0.2% MAD	-0.6%
Two independent idle machines heap per unit	3.4 KiB	0.1% MAD	3.4 KiB	0.0% MAD	-0.6%
Idle parent with one child heap per unit	5.8 KiB	0.0% MAD	5.8 KiB	0.0% MAD	0.0%
Parent with observed child registry heap per unit	10.0 KiB	0.0% MAD	10.0 KiB	0.0% MAD	+0.0%
Parent with observed invoked child snapshots heap per unit	6.3 KiB	0.0% MAD	6.3 KiB	0.1% MAD	-0.4%

Process runtime reference change from base

Metric	Base	Base variability	PR	PR variability	Difference
Start and stop a raw generic process	15,778 processes/s	0.5% MAD	15,420 processes/s	0.4% MAD	-2.3%
Start and stop a raw compiled process	62,500 processes/s	1.0% MAD	62,267 processes/s	0.1% MAD	-0.4%

Regression guard

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

Versions and interpretation

• Effect Machine: 0.19.0

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.