pomerium / pomerium / 38771402980

54%

Build Type

push

github

Committed by web-flow

Commit Message

fix(databroker): postgres conditional write must not restore a deleted record (#6857)

## Summary

On Postgres, a conditional `Put` (`if_match_version`) at version N > 0
succeeds when the record was deleted after it was read, and re-creates
it. The file and in-memory backends reject that write with
`RECORD_VERSION_MISMATCH`, since a deleted record has no stored version.

Postgres now does the same. A conditional write at version N > 0 only
updates a record that still exists at version N; otherwise it fails with
`RECORD_VERSION_MISMATCH` and nothing in the batch is written. Only a
version-0 write can create a record. This holds when the delete is
concurrent too: the write waits for the delete, then fails instead of
re-creating the record. The write stays a single compare-and-swap
statement with no extra locking. Unconditional `Put`, conditional
creates and conditional deletes are unchanged.

Without this, a read-then-conditional-write caller can undo a delete: a
session refresh racing a revocation brings the revoked session back.

## Related issues

Fixes a regression from #6773. It is in no release yet, so no backport.

## User Explanation

None. Internal databroker API; the bug is unreleased.

## AI disclosure

Claude Code wrote the fix and tests from my bug description and
constraints; I reviewed.

## Checklist

- [x] reference any related issues
- [x] updated unit tests
- [ ] add appropriate label (`bug`)
- [x] disclosed AI usage (or wrote "none") per AI_POLICY.md
- [ ] ready for review

Coverage Stats

13 of 25 new or added lines in 2 files covered. (52.0%)

28 existing lines in 10 files now uncovered.

34842 of 65038 relevant lines covered (53.57%)

316.75 hits per line