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chained-run

An advisory by default: it explains, and blocks nothing, on magus runs sequenced with && or ;, which a pipe of the same stages runs ordered and fail-fast.

What it catches

Magus runs sequenced with && or ;, which a pipe of the same stages runs ordered and fail-fast.

Why

A pipe of magus runs keeps what the chain was for: stages whose projects overlap run in order, a failed stage stops the ones after it, and the last stage exits with the first failure (MGS3030), so no set -o pipefail is needed. It differs from && in one way, which the deny states: a stage on disjoint projects runs alongside the others and finishes even after an upstream stage fails. The pipeline still exits red. The same target chained over several project sets is served the pipe too, which keeps the order the chain chose; the deny names the one call for when order does not matter. It advises instead, and says why, wherever the pipe would do something else. That covers ||, a redirect or any other command on the line, and a later affected stage, which reads its projects from the diff before the upstream's writes land: affected generate:rw stays its own call ahead of affected ci. It also covers a later run naming no projects, which would inherit the upstream's; a stage that reads stdin, takes no locks, or writes -o output upstream; stages on different binaries or roots; a stage after go-build or build in magus's own checkout, since every stage starts at once and would run the ./magus being replaced; and Windows, where no pipe proves its upstream.

Default and override

By default this rule takes the decision advise. A workspace sets it by name, in its root magusfile, to deny, advise or off:

magus\guard.builtins({"chained-run": "deny"})

A loosening takes effect once it is committed; a tightening applies at once.

Seeing it

A verdict names its rule in brackets, which is how you got here:

advise [chained-run]: ...

magus describe rule chained-run prints the same entry at a terminal, and magus describe rules lists every rule this workspace enforces.

See also

ReferencePages in this section. ChangelogEvery change to magus, newest first, in Keep a Changelog format, starting with the unreleased entries. Generated from changes/unreleased/ and releases/*.yaml. Cache modelHow magus computes a content-addressed cache key from a target's declared inputs, replays outputs on a hit without rerunning the body, and stores it all as plain files under .magus. ConcurrencyHow magus coordinates parallel work: the intra-process scheduler that parallelizes a single run, the cross-process workspace lock that keeps two separate magus invocations from clobbering each other's outputs and cache, and the broker-held machine budget that keeps every magus on the host from oversubscribing it.
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Glossary

Workspace

The magus root directory that owns a set of projects and shared config; the unit magus operates over. See workspace.

Project

A directory magus recognizes as a unit of work (it has a magusfile); the unit of caching, scheduling, and dependency tracking. See workspace.

Magusfile

The magusfile.buzz that declares a project's targets (as export funs) and binds its spells. See targets.

Target

A named operation (build, test, ...) you invoke with magus run <target>; it may compose a spell's tool-native operations and depend on other targets. See targets.

Op

A single tool-native command a target composes (long form: operation); the middle of the work hierarchy (Spell to Op to Target). See operations.

Buzz

The language magusfiles are written in (the .buzz engine). See engines.

Affected

The set of projects touched by a change; magus affected <target> runs a target only over them. See affected.

CI

An ordinary magusfile-defined target you compose yourself with magus\needs: magus does not hardcode its stages. Magus.RunCI treats it specially only in that it strips the rw charm, it is the anchor magus affected ci keys off, and a selected scope with no project declaring it is a load error rather than a silent no-op. See targets.

Window

The terminal a command runs in. It keys fire-once notices for a caller no host gave a session, and is never recorded as a session.

Run

One target executing under one magus invocation, such as magus run test web or magus affected ci. A run keeps its captured output behind an output reference. Every magus run is a run whether or not any job asked for it; see Job for how the two relate.

Advisor

One read-only check from the advice suite: it reads the changeset through magus and writes one titled section of findings. The same advisors run as a pull request comment in CI and inside magus diff --impact locally.

Conventions

This page uses none of the site's convention markers. The full set is on the conventions page.