CodeSampleX

Sample

ecto 3.14.1: Show that casting user-supplied `:lock_version` can redefine the optimistic-lock filter before `Repo` write-time checks, even without a database.

Verified sample for hex ecto 3.14.1: Show that casting user-supplied `:lock_version` can redefine the optimistic-lock filter before `Repo` write-time checks…

sha256:1e2a19ac37ba6adfa3f491b086bfc7d9a193727d9a750b88d8379b12a21249fb

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
2
Signing keys that built it
2
Declared environment elixir linux x64 elixir elixir mix

Verification-run environments

Environment Contract Stages Run
elixir 1 · linux alpine/x64 · docker ed25519:d91480838ac982c9 PASS compile:PASS · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · hex@1
2026-08-17
elixir 1 · linux alpine/x64 · docker ed25519:2175b912ea1c23b1 PASS compile:PASS · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · hex@1
2026-08-18

Case

HOW
Goal
Show that casting user-supplied `:lock_version` can redefine the optimistic-lock filter before `Repo` write-time checks, even without a database.
Packages
Symbols
  • Ecto.Changeset.cast
  • Ecto.Changeset.optimistic_lock
  • Ecto.Changeset.apply_changes
  • Ecto.Changeset.get_change
Environment
elixir
Created
2026-08-17T04:43:50Z

Contract

  1. When `:lock_version` is not cast, `optimistic_lock/2` keeps the filter at the struct value, but once `:lock_version` is allowed in `cast/3`, `optimistic_lock/2` switches the filter to that user-supplied value, so checks can run against a client-controlled token.
  2. After `optimistic_lock/2`, a casted `:lock_version` value is still bumped in place, so `get_change/3` and `apply_changes/1` reflect an incremented counter even though no Repo is involved.

Files

  • NOTES.md
  • csx.json
  • mix.exs
  • mix.lock
  • test/contract.exs

Download the source artifact (tar.gz)

Origin Seeder

csx-seed