# LibTmux::Batch

- **Package:** LibTmux
- **Language:** Raku
- **Kind:** module
- **Source:** https://github.com/libtmux/libtmux-raku/blob/e76160bcce6e03976d49424da15b7c31afb2c68e/lib/LibTmux/Batch.rakumod#L4
- **Page:** https://libtmux.org/en/raku/latest/reference/libtmux-batch/

# Partial outcomes, not transactions

Operation requires either acknowledgement-only or a Promise of Evidence. In
command scope, Complete means a successful command acknowledgement; it does not
prove an asynchronous external effect. In effect scope, Complete additionally
requires matching named Evidence with satisfied=True. Evidence is supplied by
the caller, who must arm and correlate its operation-specific observer before
dispatch. A name match is not proof of causation. No caller callback runs inside
the batch. Its deadline bounds waiting, not the caller's independent work.
Evidence Promises are one-shot: rerunning effect-aware commands requires newly
armed evidence, rather than treating an old observation as a new completion.

The immutable Batch captures finite membership, preserving order and rejecting
duplicate names. Empty membership is a no-op. run/run-async accept an existing
Runtime, Control connection or compatible CommandExecutor and never close it.
Adapters must validate without effects, honor absolute deadlines and cancellation,
settle their execution Promises with Receipt values, and preserve effect certainty
in typed errors.
All operations share one absolute deadline. A supplied ` :deadline(Instant) `
can shorten the local ` timeout-ms ` budget; it never extends that budget. The
same Instant is passed to every command and retained in the report. An already
expired deadline skips dispatch. The executor may use a shorter local limit. Cleanup retains
the executor's own separate bounds. Cancelling a dispatched Control request can
close that connection according to its documented delivery contract.

Every position receives an OperationResult. Failure stops subsequent dispatch
by default; on-error=continue attempts remaining operations while time and
cancellation permit. Never-dispatched suffixes are Skipped. A timed out or lost
in-flight effect is Indeterminate, even if acknowledgement was received. The
original exception and its outcome remain available through error/error-outcome.
No rollback is attempted or promised, and reports retain no executor owner.

output-budget-bytes defaults to 8 MiB. After each operation, Batch counts receipt
output and Command exception stdout/stderr, following shared Command causes only
once. Reaching or exceeding the threshold stops further dispatch even under
on-error=continue. The complete threshold-crossing receipt/error is retained and
the undispatched suffix is Skipped. This is an admission threshold: retained
output can reach the budget plus one executor-bounded response. It is not a hard
RSS cap; object overhead, arbitrary adapter/evidence exceptions and independent
caller-owned tasks remain outside that bound. Such adapters must accurately
report Receipt.output-bytes and bound their own responses.

## Members

### Other members

- [`Batch`](/en/raku/latest/reference/libtmux-batch-batch/) (class): A finite replayable sequence of explicit commands, without transaction semantics.
- [`Evidence`](/en/raku/latest/reference/libtmux-batch-evidence/) (class): Caller-supplied evidence for one named operation, not a command acknowledgement.
- [`Operation`](/en/raku/latest/reference/libtmux-batch-operation/) (class): One immutable command and an explicit completion contract.
- [`OperationResult`](/en/raku/latest/reference/libtmux-batch-operationresult/) (class): One position's outcome, preserving its acknowledgement and original exception.
- [`Report`](/en/raku/latest/reference/libtmux-batch-report/) (class): Captured per-operation results. No runtime, control owner or caller task is retained.