Field-presence policy, starting price 12.50
The following is a synthetic patch contract chosen for this example. A deliberately absent optional price is unchanged. A short CSV row is malformed and must be rejected before this contract is applied; it is not the deliberately absent case. Zero prices are prohibited only by this example's stated purchasing rule.
If the matrix is wider than the box, scroll horizontally to read every column. Keyboard: focus the matrix and use Left/Right.
submitted state | disposition | price after
optional price deliberately absent| unchanged | 12.50
price present, empty string | hold-blank | 12.50
price present, 0.00 | hold-zero | 12.50
price present, 13.25 | replace | 13.25
explicit authorised clear | clear | null
explicit clear without authority | hold-clear | 12.50Product-absence policy, three existing products
The existing set is part-a, part-b and part-c. The incoming feed contains part-a only. Declared coverage is part-a and part-b, so part-c is outside scope. A confirmed complete snapshot marks part-b unavailable under this authored rule; it never deletes it or declares discontinuation. A delta leaves omitted products unchanged.
If the matrix is wider than the box, scroll horizontally to read every column. Keyboard: focus the matrix and use Left/Right.
feed mode and completion | disposition | mark unavailable | unchanged
delta, complete update | accept | none | part-b, part-c
snapshot, complete | accept | part-b | part-c
snapshot, incomplete | hold-completeness | none | part-a, part-b, part-c
unknown mode | hold-mode | none | part-a, part-b, part-cLimits and acceptance
The local authored model tests these dispositions with invented values. It does not parse a file, validate supplier completeness, execute database writes or recover a real import. In an actual application test, compare prior and resulting state for every rejected case, not merely the returned status. Approve the purchasing rule before implementing it.
- An empty CSV value has no universal business meaning.
- No stock, prices or accounts were changed.
- A source-completeness declaration needs authoritative evidence for the exact coverage.
Priced enquiry and non-fit
An existing local field-presence bug may fit the regression-test repair from £295 after bounded reproduction and a fixed quote. One new change-preview interaction may fit the feature-preview offer from £750 only in an existing app with an already available isolated private preview, synthetic data and no sensitive handling changes. Do not bundle both into one assumed small job. Live feed retrieval, stock publication, data recovery and a new inventory system are excluded. Send invented prior state, submitted state and desired disposition, not files or credentials; prices are untested and payment follows agreed checks and sign-off.
Sources and limits
- Python CSV missing-field and None serialization behaviour Checked 2026-10-11.
- Missing row fields and explicitly empty strings can differ on read; writing None as an empty string loses that distinction.
- W3C tabular metadata: declared null markers Checked 2026-10-11.
- Metadata can declare null markers; the default null marker is an empty string.
- Current local-repair terms Checked 2026-10-11.
- Current preview-feature terms Checked 2026-10-11.