fix(objectql): hook 条件对完整 record 求值 —— stored ⊕ payload,与 #4649 同源 (#4770)

A declarative hook `condition` was evaluated against `ctx.input.data` — the
fields the current write happens to carry. `ctx.previous` sat behind it,
unreachable, and the two were never merged, so a condition could only reference
a field the update touched. Anything else aborted the CEL expression with
`No such key`, which the gate swallowed into `false` plus one WARN line.

For a guard-style hook that reads as "let it through"; for an audit-style hook
it reads as "do not record it". `showcase_audit_task_completion`
(`record.done == true`) therefore did NOT run on the most ordinary updates
there are — change the status, change the assignee — and the only trace was ten
warn lines per showcase boot.

The record a condition reads is now built exactly the way a validation
predicate's is (#1871 / #4649): stored ⊕ payload, made total over the object's
DECLARED fields, `null` when a declared key is in neither. `materializeDeclaredFields`
moves out of `validation/rule-validator.ts` into `declared-fields.ts` and is
shared by both paths, because `record.done == true` must not mean two different
things depending on which surface evaluates it.

Declared-only is the load-bearing half: a typo'd or undeclared key stays
unevaluable and is still reported. Materialisation runs only when the persisted
state is in hand — an insert, or an update whose prior row was fetched — so a
predicate bulk update keeps its payload rather than gaining nulls that
contradict N stored rows. `ctx.ql.getObject()` is an in-memory registry read;
no code path fetches a record it did not already load.

Out of scope, deliberately unchanged: what happens when a condition is STILL
unevaluable after merging (warn + treat as false). Its failure direction is
opposite for guard and audit hooks and is tracked separately.

`has(...)` is not a null guard once the record is total — the showcase's
over-budget condition is rewritten with `!= null`, and the hook docs that
prescribed `has(record.x)` are corrected with it.

Evidence: `pnpm dev -- --fresh` on this branch logs 0 `condition evaluation
failed` lines; the same boot with the fix reverted logs exactly the 10 the issue
reported.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018iARDqtrhQgz6fVHDeDkbQ

Author: claude

.changeset/hook-condition-merged-record.md

@@ -0,0 +1,59 @@
+---
+'@objectstack/objectql': minor
+---
+
+**A declarative hook `condition` is now evaluated against the RECORD — the stored row overlaid with this write's payload — not against the update payload alone (#4770).**
+
+⚠️ **Behaviour change — read this before upgrading.** The condition gate used to evaluate
+against `ctx.input.data`: only the fields the current write happened to carry.
+`ctx.previous` sat behind it, unreachable, and the two were never merged. So a condition
+could reference only a field the update *happened* to touch; referencing anything else
+aborted the CEL expression with `No such key` — which the gate swallowed into `false`,
+leaving one WARN line as the sole trace.
+
+For a guard-style hook that reads as "let it through"; for an audit-style hook it reads as
+"do not record it". `condition: "record.done == true"` on an audit hook therefore did NOT
+run on the most ordinary updates there are — change the status, change the assignee —
+because `done` was not in the payload.
+
+The record a condition reads is now built the same way a validation predicate's is
+(#1871 / #4649, via one shared helper so the two cannot drift):
+
+- **stored ⊕ payload** — the prior record overlaid with this write's data, so a condition
+  may reference any field of the record, not just the changed ones. The payload still
+  wins for the fields it carries.
+- **total over the object's DECLARED fields** — `null` for a declared field present in
+  neither, so a driver that stores only the columns it wrote no longer decides whether an
+  expression is evaluable.
+- **declared fields only** — an undeclared or typo'd key (`record.stauts`) stays
+  unevaluable and is still reported, exactly as before.
+
+Materialisation happens only when the persisted state is actually in hand — an insert, or
+an update whose prior row was fetched. A predicate (`multi: true`) bulk update carries no
+prior row, so its payload is left as it is rather than gaining `null`s that would
+contradict the stored rows. No code path fetches a record it did not already load.
+
+**What you may see after upgrading**
+
+- **Conditions that never fired start firing.** A hook gated on a field the payload rarely
+  carried was silently skipped; it now evaluates. This is the declaration finally being
+  honoured, but expect hooks to run on writes where they previously did not.
+- **A condition is now about the record's STATE, not about this write's diff.**
+  `record.done == true` fires on every update of a task that *is* done, not only on the
+  update that set it. A condition cannot express a transition today — the CEL scope binds
+  `record` only.
+- **Conditions guarded with `has(...)` need `!= null`.** `has(x)` asks whether the key is
+  **present**, and a declared field holding `null` is present — so
+  `has(a) && has(b) && a > b` still faults on `null > null`. Same lesson as #4649:
+
+  ```diff
+  - condition: 'has(record.spent) && has(record.budget) && record.spent > record.budget'
+  + condition: 'record.spent != null && record.budget != null && record.spent > record.budget'
+  ```
+
+  `has()` remains correct for asking whether an **undeclared** key exists.
+
+**Unchanged, deliberately:** what happens when a condition is *still* unevaluable after
+merging — it is logged at WARN and treated as `false`, as before. Whether that fallback
+should differ by hook category (a guard fails open, an audit fails silent) is a separate
+decision, tracked on its own issue.

examples/app-showcase/src/data/hooks/index.ts

@@ -63,11 +63,15 @@ export const WarnOverBudgetHook = {
   label: 'Warn On Over-Budget Project',
   object: 'showcase_project',
   events: ['afterUpdate'] as LifecycleEvent[],
-  // Guard with has(): an afterUpdate fired by a partial write (e.g. the
-  // task-rollup that only touches task_count) carries a record WITHOUT
-  // spent/budget, and CEL throws "No such key" on a bare `record.spent`.
-  // has() is the missing-key-safe macro — the hook simply skips those.
-  condition: "has(record.spent) && has(record.budget) && record.spent > record.budget",
+  // Guard with `!= null`, NOT with `has()` (#4770, same lesson as #4649). A
+  // condition is evaluated against the STORED record overlaid with this
+  // write's payload, made total over the object's declared fields — so a
+  // partial write (the task-rollup that only touches task_count) still sees
+  // spent/budget, and `has(record.spent)` is uniformly TRUE for a declared
+  // field, including one holding null. Only `!= null` actually keeps
+  // `null > null` — which CEL has no overload for — from aborting the
+  // expression.
+  condition: "record.spent != null && record.budget != null && record.spent > record.budget",
   body: {
     language: 'js' as const,
     source: "var r = ctx.result || ctx.input || {}; ctx.log.warn('project over budget: ' + (r.name || r.id || 'unknown') + ' (' + r.spent + ' / ' + r.budget + ')');",

packages/objectql/src/declared-fields.ts

@@ -0,0 +1,58 @@
+// Copyright (c) 2025 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * Make a record TOTAL over an object's DECLARED fields.
+ *
+ * Shared by the two places that evaluate a CEL expression against "the
+ * record": object-level validation predicates
+ * (`validation/rule-validator.ts`, #1871 / #4649) and declarative hook
+ * `condition`s (`hook-wrappers.ts`, #4770). They used to disagree — a
+ * predicate saw a total record while a hook condition saw only the fields the
+ * current write happened to carry — which is precisely the drift this module
+ * exists to prevent: an author cannot be expected to know that the same
+ * `record.done == true` means two different things depending on which surface
+ * reads it.
+ *
+ * CEL is strict about missing keys: `record.x` on a record that does not carry
+ * the key `x` aborts the whole expression with `No such key`, which is NOT the
+ * same as reading `null`. Whether a key is carried is a property of the DRIVER
+ * (a driver that stores only written columns returns a record missing every
+ * column the write never touched), not of the data — so without this an
+ * expression's evaluability depends on storage internals the author cannot
+ * see.
+ *
+ * Scope is deliberately the object's **declared fields only**. Materialising
+ * every key an expression happens to name would paper over author typos: a
+ * `record.stauts` must stay unevaluable so it is reported (fail-closed for
+ * validation, #4649) rather than silently read as `null` and quietly answered
+ * "no violation" / "condition false".
+ *
+ * `undefined` counts as absent (not just a missing key): CEL treats an own key
+ * holding `undefined` exactly as it treats no key at all.
+ *
+ * ## Only ever call this when the record's persisted state is IN HAND
+ *
+ * On insert there is nothing to know — absence genuinely means "no value". On
+ * update it is knowable only when the prior row was actually fetched. Without
+ * it, defaulting a declared field to `null` would not be materialising an
+ * absent value, it would be FABRICATING one that contradicts the stored row.
+ * Callers decide; this function only applies the rule.
+ *
+ * ## Consequence worth knowing before writing an expression
+ *
+ * Because a declared field is always present afterwards, `has(record.<declared
+ * field>)` is uniformly TRUE (a materialised `null` is a present key holding
+ * null — CEL's own rule). `has()` therefore guards against an UNDECLARED key,
+ * not against an empty value; test emptiness with `record.x != null`.
+ */
+export function materializeDeclaredFields<T extends Record<string, unknown>>(
+  record: T,
+  fields: Record<string, unknown> | undefined | null,
+): T {
+  if (!fields || typeof fields !== 'object') return record;
+  const target = record as Record<string, unknown>;
+  for (const name of Object.keys(fields)) {
+    if (target[name] === undefined) target[name] = null;
+  }
+  return record;
+}