# `CommitOptions.expectRevision`

> Contract 2.0.0 · package sha256 `a857eca95b35921109faf997094bb4192f12527d9d0fcd4be7e97f06425bad6e` · generated from `configurator-runtime.d.ts` by `services/onsite-scripter/scripts/build-contract-docs.mjs`; edit the source, not this file.

Property of [`CommitOptions`](CommitOptions.md) · inherited by [`WriteOptions`](WriteOptions.md), [`TransactionOptions`](TransactionOptions.md) · stable · since 2.0.0

```ts
expectRevision?: number;
```

If-match on [`session.revision`](Session.revision.md). A mismatch refuses the write ('refused', reason 'conflict');
nothing runs. While a transaction is open or queued ahead of it, or while a recorded write
ahead of it in the write queue is pending, it is refused 'busy' at once. Behind pending
look-only writes alone ([`apply`](Writer.apply.md), [`Collection.set`](Collection.set.md), [`stage.set`](Stage.set.md)) it waits its turn: those never
move `revision`. It waits behind a dry run too, a write or a transaction with `dryRun: true`,
open or queued: a dry run never moves `revision` (spec section 6.1, O2e).

**Default:** undefined (no check)

## Generic-API test (spec 3.1)

| Rule | Result |
| --- | --- |
| 1. Neutral name | pass: `expectRevision` names no product |
| 2. A precedent | not recorded: no ledger row (coverage.json) names this member or its owner |
| 3. Two apps, or labs | not recorded: no ledger row names this member or its owner |
| 4. The cheaper fix first | not recorded per member (Appendix B decides it per need) |