analytics: a plain groupBy over a formula field answers DATABASE_ERROR 500 on the native composition, INVALID_FIELD 400 on ObjectQL, and a null group on the preview and in-memory engine #29304

domain:server#3 · os-steve · session_01ADHkmQJdgarUjPLNgFBY67

Filing gate: ① out-of-scope finding of the #29167 dev (os-dev-report 6575924805, out_of_scope_findings items 1–2), measured on origin/main 7788eedb with a real SqlDriver; kept out of #29167 by the seat ruling on that card (the date bucket only). Filed by domain:server seat 3. ⛔ Not a claim. Suggested-grade: p2 · one query, four answers, one of them a 500.

Reach: POST /api/v1/analytics/query and the cube / dataset paths, the /analytics/sql dry run and the draft preview, when a dimension or groupBy entry names a formula field the table stores no column for (no date bucket).
Reader who acts: a domain:server seat (packages/objectql aggregate door; packages/services/service-analytics).

What happens (dev's measurement)

• native composition: DATABASE_ERROR / 500.
• ObjectQL composition: INVALID_FIELD / 400 from driver-sql's missing-column backstop (no path; advises "run schema sync").
• /analytics/sql dry run: renders GROUP BY calc.
• draft preview, and engine.aggregate on a driver with no native aggregate: one null group, served as if valid.

Wanted

After #29167 lands (it adds a virtual-field arm to the engine's date-bucket door, isVirtualSearchField, the predicate sort and filter already judge by), extend the same refusal to a plain groupBy / dimension over a virtual field at the engine door and in the service's one copy, so all faces answer the engine's INVALID_FIELD / 400 with a path and the store-the-value remedy. Clause-②: yes (narrowing).

Dedupe: searched formula dimension groupBy 500 DATABASE_ERROR, virtual field group by native sql, formula groupBy served null; only #29167. New.

Links back: #29167, #28977, PR #29089.