FA-44740 / Data systems / Member archive

Schema union reuses the first batch schema for later batches · case 05

Schema union reuses the first batch schema for later batches.

Member previewVariant 5 · 3 implementations · 7 checks per implementation

Case contract

Union batches using stable numeric field identities. The output schema is an ordered list [id,current_name,default]; batch schemas map old names to IDs. Project each batch row into output order, use defaults only for absent columns, and preserve explicit nulls and all rows.

Why this case matters

A bounded deterministic data engine model makes representation and changelog faults reproducible.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
reordered batch	`[[5, 6], [7, 8]]`	`[[5, 6], [8, 7]]`	Failed

MEMBER ARCHIVE

The complete case is available to members.

This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

Member access is invitation-based. Sign in with your invited account to inspect the sources.