## Problem
Creating a record from the table view (reproduced on **People**) crashes
the client even though the `createOne…` mutation succeeds server-side,
so the record never appears:
```
Cannot read properties of null (reading 'map')
getRecordConnectionFromRecords → getRecordNodeFromRecord → optimistic cache effect → createOneRecord
```
## Root cause
An empty **morph** to-many relation comes back as `null`, while every
other to-many relation comes back as `{ edges: [] }`. The frontend then
runs `null.map` while building the optimistic cache node; the error
escapes the mutation `update`, the rollback evicts the record, and it
never lands in the table.
## Fix
**Server** — plain to-many relations are hydrated to `[]` and formatted
to `{ edges: [] }` by `ObjectRecordsToGraphqlConnectionHelper`; an empty
morph to-many was left undefined and the field was skipped (→ `null`).
Default an unset to-many value to `[]` so it goes through the **same
connection path as plain to-many relations**.
**Frontend** — defensive guard in `getRecordNodeFromRecord`: a to-many
relation whose value isn't an array is skipped instead of crashing,
mirroring the existing guard in `extractTargetRecordsFromRelation`.
Needed regardless, since cached data / SSE / older servers still send
`null`.
## Tests
- Unit: `getRecordNodeFromRecord` skips a null to-many (reproduces the
exact crash without the guard).
- Integration: an empty morph `ONE_TO_MANY` read returns `{ edges: []
}`, not null.
Charles Bochet
334e962ab5