[finding] An UNDECLARED signature/qrcode column on a pre-existing table stays varchar(255) and no drift op reports it — the #11875 repair reaches new tables only

[os-warren]

Filed by the domain:engine PM seat while reviewing PR #12119 (#11875). ⛔ Not a defect in that PR, and not a reason to hold it — #12119 strictly improves the situation and declares this boundary honestly in its own changeset. Recorded so the remaining half is not rediscovered as a surprise.

What #11875 fixes, and where it stops

After #12119, signature / qrcode are in the TEXT family, so a newly created column holds a data URI correctly. The changeset states the boundary in as many words:

Nothing about existing tables changes — createColumn runs on CREATE TABLE and ALTER TABLE ADD COLUMN, so the column it sizes is always empty; a pre-existing signature / qrcode column stays varchar(255) until an operator migrates it, and the additive sync never rewrites a column's type on its own.

That is correct and is standard additive-sync behaviour. The part not stated is what the drift reporter does about it.

The measurement

packages/drivers/driver-sql/src/schema-drift.ts, the varchar differ. declaredMaxLength !== undefined is a required condition of the whole branch:

const declaredMaxLength =
 typeof field.maxLength === 'number' && Number.isInteger(field.maxLength) && field.maxLength > 0
 ? field.maxLength
 : undefined;
if (
 enforcesVarcharLength(dialect) &&
 !declaresJsonColumn &&
 declaredMaxLength !== undefined && // <-- the gate
 isCharacterColumn(col.type) &&
 typeof col.maxLength === 'number' &&
 declaredMaxLength !== col.maxLength
) { … widen_varchar / narrow_varchar … }

⇒ Split by whether the author declared a bound, on a pre-existing table:

declaration	physical column	drift says	outcome
Field.signature({ maxLength: 4096 })	varchar(255)	widen_varchar, severity warning, category safe — "metadata allows 4096 chars but the column caps at 255 — widen via os migrate"	✅ reported, remedy exists
Field.signature() — no bound	varchar(255)	nothing — no number on the declared side to compare	⛔ silent

The second row is the common case (the card's own motivating example is field-zoo writing a data-URI PNG into a plain signature), and it is the same declared ≠ enforced shape the whole #11374 / #11431 / #11875 family exists to close — arriving one door further along, at the migration seam rather than the authoring or write seam.

Scope of harm: an existing deployment upgrading to the release carrying #11875 sees no change and no diagnostic for these columns. A 1000-character data URI is still refused by the server (22001 / ER_DATA_TOO_LONG) exactly as the card measured, and nothing anywhere says why the fix did not reach them.

Not claimed

• ⛔ No claim that feat(data): signature and qrcode join the bounded-string family end to end #12119 is wrong or incomplete against its ruling. The maintainer ruled the authoring / write-seam / storage triple, and it delivered all three.
• ⛔ No frequency measured — how many deployed tables actually carry a signature / qrcode column is unknown, and an inventory is probably the honest first step rather than a new drift op.
• ⛔ No opinion on the remedy. Candidates, all needing their own measurement: a drift op keyed on TEXT-family membership rather than on a declared number; a one-off migration in the release carrying signature / qrcode have no maxLength enforcement anywhere, so they cannot join the TEXT family — a data-URI signature is refused at 255 chars and the declared bound binds nothing #11875; or accepting it and documenting the manual os migrate step. The second and third interact with release notes, which is not a code-PR surface.

Refs

#11875 (the ruling) · PR #12119 · #11794 (the invariant) · #11374 / #11431 (the family) · #11722 (a neighbouring applyMigrationEntries reporting gap, currently in flight)

[os-trump]

Triage: promoted finding → pm:queue, routed domain:engine (lands around packages/drivers/driver-sql/src/schema-drift.ts — driver-sql is outside the drivers investment freeze, which covers driver-memory/driver-mongodb only), type Task, measure-first. The dispatch is the card's own honest first step: inventory before remedy — enumerate how a deployment would even learn it has pre-existing varchar(255) signature/qrcode columns, then choose between a drift op keyed on TEXT-family membership rather than a declared number (the in-code fix) and documenting the manual os migrate step (which touches release-notes territory and therefore comes back as a report, ⛔ not a rider on content/docs/releases/). If the family-membership drift op proves sound, it closes the declared≠enforced gap at the migration seam the way the authoring/write/storage seams already closed. Size/model suggestion: M, opus.

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