feat(lint,spec): L2 action body 写不存在字段从盲区变为作者时 lint 告警 (#4271)

The write-set lint #4305 gave L2 hook bodies now covers the other surface that
carries one. An action body is the same artefact — same `HookBodySchema`, same
`HookBodySchema.safeParse` in `actionBodyRunnerFactory`, same QuickJS sandbox —
so it fails the same way: `ctx.api.object('crm_deal').update({ stag: 'won' })`
succeeds, returns success to the caller, and the unknown column never lands.

New rule `action-body-write-unknown-field`, advisory, wired into
REFERENCE_INTEGRITY_RULES so `os validate` / `os lint` / `os compile` all report
it. Both places the runtime reads actions from are walked (top-level `actions`
and `objects[].actions`); a defineStack-merged action, which lives in both, is
reported once at its authored path.

Only the `ctx.api` write family carries over. An action's `ctx.input` is its
PARAMS bag, not a record, so resolving those names against object fields would
flag every correctly-named parameter. `ctx.record` is not a write surface
either: the runner hands the body a plain snapshot and never writes it back, so
`ctx.record.x = …` is discarded for declared and undeclared fields alike — a
different defect, and flagging only its undeclared half would imply the
declared half persists.

So the rule ships a declared PARTITION of the shared HOOK_BODY_WRITE_PATTERNS
— ACTION_BODY_WRITE_PATTERN_IDS plus ACTION_BODY_WRITE_EXCLUSIONS, each
exclusion carrying its reason — tested to cover the shared ledger exactly, so a
fourth pattern landing on the hook side fails this rule's test until someone
classifies it. Every applicable pattern is proved end-to-end through the full
validator; every exclusion is proved extractable-but-inapplicable. One
extractor, one field index, one system-column set, shared rather than copied.

The dedupe is by value (bound object + name + body source), not by object
identity the way collectBundleActions can afford: the suite runs on the parsed
stack and parsing rebuilds every node, so a merged action's two copies arrive
distinct-but-equal. An identity check passed the unit fixture and reported the
showcase app's one warning twice — caught by running `os validate` on it.

Lands one notch tighter than the hook side on the boot path: the only
applicable pattern is rooted at `ctx.api`, so an action body that never
mentions it does not parse at all, let alone load the ~9 MB TypeScript
compiler. Guarded by lazy-deps.test.ts.

spec: ScriptBodySchema and ActionSchema.body point at the action-side rule and
spell out that ctx.input (params) and ctx.record (a discarded snapshot) are not
record-write surfaces. Doc comments only — all 8 generated artifacts verified
unchanged.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: os-zhuang

.changeset/action-body-write-set-lint.md

@@ -0,0 +1,63 @@
+---
+"@objectstack/lint": minor
+"@objectstack/spec": patch
+---
+
+feat(lint): L2 action-body writes to undeclared fields warn at author time (#4271)
+
+The write-set lint that #4305 gave L2 hook bodies now covers the other surface
+that carries one. An action body is the same artefact: the same
+`HookBodySchema` union, parsed by the same `HookBodySchema.safeParse` in
+`actionBodyRunnerFactory`, run in the same QuickJS sandbox. So it fails the
+same way — `ctx.api.object('crm_deal').update({ stag: 'won' })` inside an
+action succeeds, returns success to the caller, and the unknown column simply
+never lands. Half the surface was still blind.
+
+**New rule — `action-body-write-unknown-field` (advisory).** Wired into
+`REFERENCE_INTEGRITY_RULES`, so `os validate`, `os lint` and `os compile` all
+report it; it never blocks a build. Both places the runtime reads actions from
+are walked — top-level `actions` and `objects[].actions` — and a
+`defineStack`-merged action, which lives in both, is reported once at its
+authored path. That dedupe is by VALUE (bound object + name + body source), not
+by object identity the way `collectBundleActions` can afford: the suite runs on
+the schema-PARSED stack, and parsing rebuilds every node, so the two copies
+arrive as distinct objects that are merely equal. An identity check passes a
+shared-reference unit fixture and then reports the showcase app's one warning
+twice — which is exactly what it did before the end-to-end run caught it.
+
+**Only the `ctx.api` write family carries over, and that is the point.** An
+action's `ctx.input` is its PARAMS bag (`input: unwrapProxyToPlain(actionCtx
+?.params)`), not a record, so resolving those names against object fields would
+flag every correctly-named parameter — a pure false-positive machine, and a
+false positive kills an advisory lint. `ctx.record` is not a write surface
+either: the runner hands the body a plain snapshot and never writes it back, so
+`ctx.record.x = …` is discarded for *declared* and undeclared fields alike —
+a different defect from "the unknown column vanishes", and flagging only its
+undeclared half would imply the declared half persists.
+
+So the rule ships a declared **partition** of the shared
+`HOOK_BODY_WRITE_PATTERNS` rather than a second ledger:
+`ACTION_BODY_WRITE_PATTERN_IDS` (today: `api-crud-literal`) and
+`ACTION_BODY_WRITE_EXCLUSIONS` (`input-property-assign`,
+`input-object-assign`), each exclusion carrying its reason. The two halves are
+tested to cover the shared ledger exactly, so a fourth pattern landing on the
+hook side fails this rule's test until someone classifies it — silence is not a
+decision. Every applicable pattern is additionally proved end-to-end through
+the full validator (prefilter, pattern filter and field check included), and
+every exclusion is proved to be about applicability rather than an
+unextractable shape: the shared extractor still sees it, and this rule still
+reports nothing for it.
+
+One extractor, one field index, one system-column set, shared with the hook
+rule rather than copied — two copies would drift into two different answers
+about what a system column is.
+
+The lint stays off the kernel boot path, and lands one notch tighter than the
+hook side: the only applicable pattern is rooted at `ctx.api`, so an action
+body that never mentions it does not even parse, let alone load the ~9 MB
+TypeScript compiler. Guarded by `lazy-deps.test.ts`.
+
+`@objectstack/spec`: `ScriptBodySchema` and `ActionSchema.body` now point at
+the action-side rule and spell out that `ctx.input` (params) and `ctx.record`
+(a discarded snapshot) are not record-write surfaces — doc comments only, no
+schema or generated-artifact change.

packages/lint/src/index.ts

@@ -271,6 +271,23 @@ export type {
   ExtractedHookBodyWrite,
 } from './validate-hook-body-writes.js';
 
+// The same write-set check on action bodies — same schema, same sandbox, same
+// silent no-op. Its ledger is a declared partition of HOOK_BODY_WRITE_PATTERNS
+// (only the `ctx.api` family survives the context change), so the two rules
+// share one extractor rather than growing two.
+export {
+  validateActionBodyWrites,
+  ACTION_BODY_WRITE_PATTERNS,
+  ACTION_BODY_WRITE_PATTERN_IDS,
+  ACTION_BODY_WRITE_EXCLUSIONS,
+  ACTION_BODY_WRITE_UNKNOWN_FIELD,
+} from './validate-action-body-writes.js';
+export type {
+  ActionBodyWriteFinding,
+  ActionBodyWriteSeverity,
+  ActionBodyWriteExclusion,
+} from './validate-action-body-writes.js';
+
 // One entry point for the reference-resolution rules above (#3583 §5 D5).
 // Adding a rule to `REFERENCE_INTEGRITY_RULES` runs it on `validate`, `lint`
 // and `compile` at once — the CLI call sites do not change.

packages/lint/src/lazy-deps.test.ts

@@ -74,15 +74,21 @@ describe('lazy dependency loading (kernel boot-path contract)', () => {
         if (loaded(dep)) fail(dep + ' was loaded eagerly, at import time');
       }
       const jsHook = (source, language) => ({ objects: [{ name: 'a', fields: { amount: {} } }], hooks: [{ name: 'h', object: 'a', events: ['beforeInsert'], body: { language: language ?? 'js', source } }] });
+      const jsAction = (source, language) => ({ objects: [{ name: 'a', fields: { amount: {} } }], actions: [{ name: 'act', label: 'Act', objectName: 'a', body: { language: language ?? 'js', source } }] });
       mod.validateHookBodyWrites(jsHook('input.x > 0', 'expression'));
       if (loaded('typescript')) fail('the hook-body write gate on an L1-only stack must not load typescript');
+      mod.validateActionBodyWrites(jsAction('input.x > 0', 'expression'));
+      mod.validateActionBodyWrites(jsAction('ctx.input.amout = 1;'));
+      if (loaded('typescript')) fail('the action-body write gate must not load typescript for a body that never touches ctx.api');
       const syntax = mod.validateReactPages(${reactStack('function Page(){ return <div>oops; }')});
       if (!loaded('sucrase')) fail('sucrase was not loaded by a react-page syntax validation');
       if (loaded('typescript')) fail('the syntax gate must not load typescript');
       if (!syntax.some((f) => f.rule === 'react-page-syntax')) fail('syntax gate produced no finding');
       const hookWrites = mod.validateHookBodyWrites(jsHook('ctx.input.amout = 1;'));
       if (!loaded('typescript')) fail('typescript was not loaded by an L2 hook-body write validation');
       if (!hookWrites.some((f) => f.rule === 'hook-body-write-unknown-field')) fail('hook-body write gate produced no finding');
+      const actionWrites = mod.validateActionBodyWrites(jsAction("await ctx.api.object('a').update({ amout: 1 });"));
+      if (!actionWrites.some((f) => f.rule === 'action-body-write-unknown-field')) fail('action-body write gate produced no finding');
       const props = mod.validateReactPageProps(${reactStack('function Page(){ return <ObjectForm mode="edit" />; }')});
       if (!loaded('typescript')) fail('typescript was not loaded by a react-page props validation');
       if (!props.some((f) => f.rule === 'react-prop-missing-required')) fail('props gate produced no finding');
@@ -117,7 +123,8 @@ describe('lazy dependency loading (kernel boot-path contract)', () => {
 
   it('loads each dep lazily in-process and the gates still work', async () => {
     const req = createRequire(import.meta.url);
-    const { validateReactPages, validateReactPageProps, validateHookBodyWrites } = await import('./index.js');
+    const { validateReactPages, validateReactPageProps, validateHookBodyWrites, validateActionBodyWrites } =
+      await import('./index.js');
 
     // Stacks without a react-source page never touch either dep.
     expect(validateReactPages({ pages: [{ name: 'p', kind: 'object' }] })).toEqual([]);
@@ -129,6 +136,17 @@ describe('lazy dependency loading (kernel boot-path contract)', () => {
     expect(validateHookBodyWrites({ hooks: [hook(undefined)] })).toEqual([]);
     expect(validateHookBodyWrites({ hooks: [hook({ language: 'expression', source: 'input.x > 0' })] })).toEqual([]);
     expect(validateHookBodyWrites({ hooks: [hook({ language: 'js', source: 'return 1;' })] })).toEqual([]);
+    // Action bodies narrow it further: the only pattern the action rule carries
+    // is rooted at `ctx.api`, so even an L2 body that writes params never parses.
+    const action = (body: unknown) => ({ name: 'act', label: 'Act', objectName: 'a', body });
+    expect(validateActionBodyWrites({ actions: [action(undefined)] })).toEqual([]);
+    expect(validateActionBodyWrites({ actions: [action({ language: 'expression', source: 'input.x > 0' })] })).toEqual([]);
+    expect(
+      validateActionBodyWrites({
+        objects: [{ name: 'a', fields: { amount: {} } }],
+        actions: [action({ language: 'js', source: 'ctx.input.amout = 1; ctx.record.nope = 2;' })],
+      }),
+    ).toEqual([]);
     for (const dep of LAZY_DEPS) {
       expect(depLoaded(req.cache, dep), `${dep} loaded before any react-source or L2-body validation`).toBe(false);
     }
@@ -151,6 +169,15 @@ describe('lazy dependency loading (kernel boot-path contract)', () => {
     expect(depLoaded(req.cache, 'typescript')).toBe(true);
     expect(hookWrites.some((f) => f.rule === 'hook-body-write-unknown-field' && f.severity === 'warning')).toBe(true);
 
+    // …and the action gate works on the same terms (#4271 follow-up).
+    const actionWrites = validateActionBodyWrites({
+      objects: [{ name: 'a', fields: { amount: {} } }],
+      actions: [action({ language: 'js', source: "await ctx.api.object('a').update({ amout: 1 });" })],
+    });
+    expect(actionWrites.some((f) => f.rule === 'action-body-write-unknown-field' && f.severity === 'warning')).toBe(
+      true,
+    );
+
     const props = validateReactPageProps({
       pages: [{ name: 'r', kind: 'react', source: 'function Page(){ return <ObjectForm mode="edit" />; }' }],
     });

packages/lint/src/reference-integrity-suite.test.ts

@@ -27,6 +27,7 @@ describe('reference-integrity suite — membership', () => {
       'validateAiToolReferences',
       'validateAiAgentAuthoring',
       'validateHookBodyWrites',
+      'validateActionBodyWrites',
     ]);
   });
 
@@ -60,6 +61,18 @@ describe('reference-integrity suite — every member actually runs', () => {
     actions: [
       // validateObjectReferences: a param pointing at an object nothing declares.
       { name: 'assign', label: 'Assign', params: [{ name: 'owner', reference: 'user' }] },
+      // validateActionBodyWrites: the L2 body persists a field crm_lead does
+      // not declare — the action returns success and the column never lands
+      // (#4271, the action half of the hook rule below).
+      {
+        name: 'score_now',
+        label: 'Score Now',
+        objectName: 'crm_lead',
+        body: {
+          language: 'js',
+          source: "await ctx.api.object('crm_lead').update({ lead_score: 100 });",
+        },
+      },
     ],
     views: [
       {
@@ -171,6 +184,7 @@ describe('reference-integrity suite — every member actually runs', () => {
     expect(rules).toContain('ai-skill-tool-unresolved');
     expect(rules).toContain('agent-authoring-withdrawn');
     expect(rules).toContain('hook-body-write-unknown-field');
+    expect(rules).toContain('action-body-write-unknown-field');
   });
 
   it('carries a gating flow-template finding through the suite (#3810)', () => {
@@ -192,9 +206,9 @@ describe('reference-integrity suite — every member actually runs', () => {
       expect(typeof f.message).toBe('string');
       expect(typeof f.hint).toBe('string');
     }
-    // Object references run first, hook-body writes last.
+    // Object references run first, action-body writes last.
     expect(findings[0].rule).toBe('object-reference-unknown');
-    expect(findings[findings.length - 1].rule).toBe('hook-body-write-unknown-field');
+    expect(findings[findings.length - 1].rule).toBe('action-body-write-unknown-field');
   });
 
   it('returns nothing for an empty stack', () => {

packages/lint/src/reference-integrity-suite.ts

@@ -66,6 +66,7 @@ import { validateAiSurfaceAffinity } from './validate-ai-surface-affinity.js';
 import { validateAiToolReferences } from './validate-ai-tool-references.js';
 import { validateAiAgentAuthoring } from './validate-ai-agent-authoring.js';
 import { validateHookBodyWrites } from './validate-hook-body-writes.js';
+import { validateActionBodyWrites } from './validate-action-body-writes.js';
 
 export type ReferenceIntegritySeverity = 'error' | 'warning';
 
@@ -118,6 +119,11 @@ export const REFERENCE_INTEGRITY_RULES: readonly ReferenceIntegrityRule[] = [
   // read-side membership (#4271). Lazy: only a hook that actually carries a
   // `language:'js'` body loads the TypeScript parser.
   { name: 'validateHookBodyWrites', run: validateHookBodyWrites },
+  // The same check on the other surface that carries a `HookBodySchema` body:
+  // action bodies, run by the same sandbox. Only the `ctx.api` write family
+  // carries over — an action's `ctx.input` is its params bag, not a record
+  // (see that module's ledger). Lazy on the same terms.
+  { name: 'validateActionBodyWrites', run: validateActionBodyWrites },
 ];
 
 /**