Fix AtomMachine selectors for emitted events

[SandroMaglione]

Summary

• preserve emitted-event types through AtomMachine.select, selectSnapshot, and matches
• preserve root and child bridge channels across internal adapter helpers and ChildOf
• cover emitting root machines from direct and bound factories, plus emitting child selectors

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

No examples changed. Local type-performance budgets and the runtime/memory smoke test passed; the CI base-versus-PR reports are authoritative.

[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)	10,439	10,439	0 (0.0%)
machine.handle (3 states, 2 transitions)	53,788	53,788	0 (0.0%)
Machine.transition (10 named branches)	96,110	96,110	0 (0.0%)
Machine.invoke (state-dependent Effect)	60,766	60,766	0 (0.0%)
machine.handle (depth 24)	180,713	180,713	0 (0.0%)
machine.handle (wide depth 16)	211,923	211,923	0 (0.0%)
machine.handle (parallel/history/choice)	125,019	125,019	0 (0.0%)
machine definition (3 independent implementations)	125,049	125,049	0 (0.0%)
machine exact input/output/error/services	108,465	108,465	0 (0.0%)
execution adapter readiness	118,832	118,832	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)	7,392	7,392	0 (0.0%)
machine.handle (3 states, 2 transitions)	43,349	43,349	0 (0.0%)
Machine.transition (10 named branches)	86,181	86,181	0 (0.0%)
Machine.invoke (state-dependent Effect)	51,920	51,920	0 (0.0%)
machine.handle (depth 24)	161,023	161,023	0 (0.0%)
machine.handle (wide depth 16)	193,232	193,232	0 (0.0%)
machine.handle (parallel/history/choice)	105,343	105,343	0 (0.0%)
machine definition (3 independent implementations)	109,503	109,503	0 (0.0%)
machine exact input/output/error/services	94,374	94,374	0 (0.0%)
execution adapter readiness	56,054	56,054	0 (0.0%)

Check times (informational)

Scenario	Base	PR
Effect only	0.02s	0.02s
Import effect-machine	0.02s	0.02s
Machine.states (3 states)	0.07s	0.06s
Machine.make (3 states, 2 events)	0.11s	0.10s
machine.handle (3 states, 2 transitions)	0.21s	0.21s
Machine.transition (10 named branches)	0.30s	0.31s
Machine.invoke (state-dependent Effect)	0.27s	0.27s
machine.handle (depth 24)	0.47s	0.44s
machine.handle (wide depth 16)	0.45s	0.46s
machine.handle (parallel/history/choice)	0.40s	0.40s
machine definition (3 independent implementations)	0.39s	0.38s
machine exact input/output/error/services	0.36s	0.34s
execution adapter readiness	0.36s	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 9V74 80-Core Processor with Node v24.19.0.

Pull request baseline

Scenario	Effect Machine
Plan counter transitions	109,609 transitions/s
Drain burst with terminal fence	330,298 increments/s
Drain burst with a change observer	313,561 increments/s
Lookup and send to one child	284,829 increments/s
Start and stop a machine	138,677 machines/s
Start and stop a parent with one child	41,210 families/s
Plan transitions through a compound state	100,391 transitions/s
Plan transitions through parallel regions	81,757 transitions/s
Drain burst through a compound state	276,062 events/s
Drain burst through two parallel regions	283,472 events/s
Drain a compound-state burst with a change observer	263,480 events/s

Process runtime reference points

Scenario	Effect Machine
Start and stop a raw generic process	25,427 processes/s
Start and stop a raw compiled process	65,007 processes/s

Memory profile	Effect Machine
Idle machine	1.8 KiB
Raw generic managed process	13.9 KiB
Raw compiled process	3.2 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	108,855 transitions/s	0.6% MAD	109,609 transitions/s	1.4% MAD	+0.7%
Drain burst with terminal fence	328,366 increments/s	0.5% MAD	330,298 increments/s	1.7% MAD	+0.6%
Drain burst with a change observer	310,130 increments/s	0.3% MAD	313,561 increments/s	1.4% MAD	+1.1%
Lookup and send to one child	281,750 increments/s	0.5% MAD	284,829 increments/s	1.0% MAD	+1.1%
Start and stop a machine	138,122 machines/s	0.4% MAD	138,677 machines/s	0.7% MAD	+0.4%
Start and stop a parent with one child	41,039 families/s	0.9% MAD	41,210 families/s	0.9% MAD	+0.4%
Plan transitions through a compound state	99,166 transitions/s	0.3% MAD	100,391 transitions/s	1.0% MAD	+1.2%
Plan transitions through parallel regions	81,376 transitions/s	0.7% MAD	81,757 transitions/s	1.1% MAD	+0.5%
Drain burst through a compound state	277,069 events/s	0.5% MAD	276,062 events/s	0.1% MAD	-0.4%
Drain burst through two parallel regions	286,759 events/s	0.4% MAD	283,472 events/s	0.9% MAD	-1.1%
Drain a compound-state burst with a change observer	262,817 events/s	0.9% MAD	263,480 events/s	0.4% MAD	+0.3%
Idle machine heap per unit	1.8 KiB	0.0% MAD	1.8 KiB	0.1% MAD	+0.1%
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	0.0% MAD	3.2 KiB	0.1% MAD	+0.0%
Two independent idle machines heap per unit	3.4 KiB	0.1% MAD	3.4 KiB	0.0% MAD	-0.0%
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	0.0% MAD	+0.0%

Process runtime reference change from base

Metric	Base	Base variability	PR	PR variability	Difference
Start and stop a raw generic process	25,246 processes/s	1.1% MAD	25,427 processes/s	0.6% MAD	+0.7%
Start and stop a raw compiled process	65,261 processes/s	0.5% MAD	65,007 processes/s	0.3% MAD	-0.4%

Regression guard

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

Versions and interpretation

• Effect Machine: 0.16.0

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.