A list with two embedding fields double-writes on generation once the write surface lands

[borisno2]

The problem

A list with more than one embedding field double-writes on generation.

RAG generates in an afterTransaction hook and protects against re-entry by comparing the stored source hash: the sudo write names only the embedding column, so its own re-entrant pass sees an unchanged hash and returns. That reasoning holds for one field. With two embedding fields on the same list, each sudo write re-enters the hook, and the other field's pass has no stored hash yet, so it writes again.

The result is redundant provider calls and redundant writes, growing with the number of embedding fields on the list.

Why it is latent today

The secured write surface does not execute at all on prisma-8 — write-pipeline.ts still speaks Prisma 6 — so the sudo write currently fails before any of this can happen. This becomes live the moment #1124 lands.

What to do

Make the re-entry protection independent of how many embedding fields a list has. Either mark the sudo write so the hook can recognise its own re-entry directly, or generate every embedding field for a row in one pass rather than one write per field.

The acceptance test is a list with two embedding fields producing exactly one provider call per field per source change.

Context

• feat(rag): embedding() as a native pgvector column with index, write denial and dimension checks #1263 / RAG's embedding field as a native vector column with index, distance function, write denial and dimension checks #1168 — where the post-commit generation hook landed and this was found in review.
• Spec: The secured surface, writes — connect, transactions, the row lock and stack-owned errors #1124 — the secured write surface, which makes this live.
• Re-point RAG's write-denial tests at context.db once the secured write surface lands (#1127) #1272 — re-pointing RAG's write tests at the real surface.
• Spec: Third-party field packages — RAG's native vector column, storage and tiptap on the new builder contract #1128 — build spec 8.

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[borisno2]

This issue's "latent" framing is void — the write surface executes now.

It was filed saying a list with two embedding fields would double-write, but only once the secured write surface landed. It has landed (deebb594), and QA confirmed by execution that creates, updates and deletes run and that embedding generation works end to end.

Two things have changed underneath this issue, and they pull in opposite directions:

• It is live, not latent. Anything described here as "the moment Spec: The secured surface, writes — connect, transactions, the row lock and stack-owned errors #1124 lands" is now simply true.
• The mechanism it describes has been replaced. PR fix(rag): say that embedding generation runs, and test it through context.db (#1128, #1272) #1332 stopped the plugin's write from re-running the hook pipeline at all. It now writes a single field through writePluginOwnedField, which runs no hooks — so the re-entry this issue's reasoning depends on may no longer happen.

Re-derive before fixing. The double-write may already be gone as a side effect, or it may survive by a different route. Reproduce it against the current code first, with two embedding fields on one list, and count the provider calls. If it no longer reproduces, close this with the reproduction recorded rather than assuming.

Note also that the source-hash short-circuit now genuinely runs in the delivered path — QA confirmed it — so any reasoning here that treated the hash comparison as untested no longer applies.

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[borisno2]

This was generated by AI during triage.

Closing as wontfix — re-derived against the current code per this issue's own comment, rather than assumed. The double-write mechanism this issue depends on no longer exists.

The reasoning was: the plugin's escalated write (sudo().db.<list>.update()) re-runs the whole hook pipeline including this list's merged afterTransaction, so a second embedding field's write re-enters the hook and, seeing no stored hash yet for itself, writes again. That write is gone. PR #1332 replaced it with writePluginOwnedField (packages/core/src/context/plugin-field-write.ts), which:

• calls updateFirst() from packages/core/src/secured/write.ts directly — a raw scoped UPDATE, not hookPipeline.run()
• never goes through runWithTransactionBoundary/runWriteInTransaction at all

So writing one embedding field's column cannot re-trigger the list's afterTransaction dispatch a second time — there is no route back into the hook chain for the re-entry this issue describes. With two embedding fields, both fire once (in sequence, within the single afterTransaction firing for the original write's commit) and neither's write causes a further firing.

One gap: there's no automated regression test pinning "two embedding fields on one list produce exactly one provider call per field per source change" (the acceptance test this issue asks for). Worth adding as a small follow-up, but the defect itself doesn't reproduce against the current write path.

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