M1 of the remaining-hierarchies work. An extension point lets a PARENT/group
node opt a module name out of sealed lexical resolution: a parent script's
`import "x"` then resolves against the INHERITING app's module (with a declared
default body as fallback) instead of the parent's sealed chain — so each
descendant app supplies its own `x`. Only the declaring parent can open the
inversion; a descendant can never make a parent's sealed import dynamic or
hijack one (the "is this an extension point" decision keys on the importer's
trusted defining node, never a script-passed value).
Resolver (executor-core):
- `ModuleSource` gains `resolve_extension_point(origin, name)` and a
chain-constrained `resolve_by_id(origin, id)`. The resolve seam checks for an
ext point on the importer's chain first; on a hit it resolves against
`App(cx.app_id)`, else the declared default, else ModuleNotFound. The Postgres
query returns Some only when the NEAREST declaration of the name is an ext
point (a peer/nearer concrete module shadows it). A group origin can't reach
app-owned rows — the trust boundary holds. Cache stays id-keyed (no bleed).
Apply (manager-core, mirrors the `vars` pattern):
- migration 0051: owner-polymorphic `extension_points` table (group XOR app),
optional `default_script_id` FK ON DELETE SET NULL, per-owner LOWER(name)
unique indexes.
- Bundle/Plan/CurrentState gain extension_points; `diff_extension_points`
(name-based, default change = Update), reconcile (upsert after scripts so the
default resolves) + prune, `validate_bundle` (module-name shape; default must
be a local module), `check_imports_resolve` (a declared/on-chain ext point
satisfies an import), and the state_token fold. Writes gate on the
script-write capability (AppWriteScript / GroupScriptsWrite).
- GET /apps|groups/{id}/extension-points so `pic pull` round-trips them — a
re-applied pulled manifest is all-NoOp, so `--prune` can't silently drop one.
CLI: `[[extension_points]]` manifest table; plan/apply build + render; pull
exports them.
Tests: 5 resolver units (inversion, default fallback, no-provider error,
no-hijack of a sealed import, no cross-tenant cache bleed), 2 diff/state-token
units, 2 journeys (per-app resolution + default fallback via invoke; pull
round-trip). Schema golden re-blessed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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