| name | fynapp-migrate-kernel |
| description | Update FynApps after the @fynmesh/kernel API changes (a type/method/event renamed, removed, reshaped, or added). Use when the kernel changed and FynApps must be brought back into alignment, or when apps report build/type errors after a kernel update. NOT for a single feature edit to one app (use fynapp-modify). |
Migrate FynApps to a changed kernel API
The FynApp contract is type-anchored: create-fynapp's
src/fynapp-contract.ts re-exports the kernel types apps depend on, so a kernel
change that breaks the contract shows up as a compile error there first.
The full playbook and its changelog ship in the installed package at
node_modules/create-fynapp/agent/MIGRATION.md (in the fynmesh monorepo:
dev-tools/create-fynapp/agent/MIGRATION.md).
Do this — follow the playbook
- Rebuild kernel types so consumers see the new surface (in the kernel
package:
tsc --build tsconfig.lib.json).
- Reconcile the anchor + contract: in the
create-fynapp package run its
build. Fix src/fynapp-contract.ts to match the new API, then update
agent/CONTRACT.md prose and any affected FynMesh examples. Add a changelog entry
to agent/MIGRATION.md.
- Migrate each FynApp per the changelog entry, conforming to
agent/CONTRACT.md. Smallest conforming edit wins.
- Check each:
cd <fynapp> && cfa check.
- Full rebuild / run to catch cross-app/federation breakage a compiler
can't see (in the fynmesh monorepo:
fyn bootstrap && fyn start).
Guardrails
- Update the anchor/contract/examples before editing apps — apps depend on them.
- A green build proves names/shapes match, not behavior. For same-type behavioral
changes, rely on the changelog + runtime checks.
- Don't trust
core/kernel/examples/simple-usage.ts or runtime.kernel
(both stale/nonexistent — see CONTRACT.md's "stale sources" list).
