Conditions

When prunes part of the graph at run start, so a pull-request run and a main-branch run can share one pipeline.

deploy := p.Workflow("deploy",
	senro.Needs("build"),
	senro.When(senro.Branch("main")))
deploy.Step("apply", exec.Command("sh", "-c", "make deploy"))

senro.Run(ctx, p, senro.WithParams(senro.Params{"branch": currentBranch}))

When exists at three levels, all taking the same Condition:

A condition is evaluated once, at the start of the run, against facts the run already has, never against anything a step produces.

The three conditions

• senro.Branch(name): true when the run’s "branch" parameter equals name.
• senro.ParamIs(name, value): true when the named run parameter equals value. Branch is this with the parameter fixed to "branch".
• senro.EnvIs(name, value): true when an environment variable equals value, read from the coordinator’s own process, not the step’s. Conditions run before any sandbox exists.

Parameters come from senro.WithParams; see Run options and outcomes, or Triggers for where branch comes from when an event started the run.

There is deliberately no And, Or or Not. Calling When more than once, at any level or mix of levels, already means AND.

senro does not read git for you

currentBranch above is whatever your pipeline binary decided, read from git or from CI’s environment. senro deliberately does not shell out to git itself: a plan depending on ambient repository state would behave differently in a container or a detached checkout.

A gated step is skipped, not failed

A step whose conditions are not all true settles as skipped_condition, and its dependents settle the same way, cascading transitively.

The difference from a failure is the run’s result:

• A run made entirely of skipped_condition steps still reports succeeded, which leaves a pull request’s run green when its Branch("main")-gated deploy does not fire.
• Dependents of an actually failed step get skipped_upstream_failed instead, which makes the run partial or failed.
• ContinueOnError does not rescue a skipped_condition dependent. It promises a dependent survives a failure, not that it runs against output that was never produced.

See Step states for the whole taxonomy.

Where to go next

• Step states: skipped_condition and how it propagates.
• Fan-out: When on a whole expansion.
• Run options and outcomes: senro.WithParams, which Branch and ParamIs read.
• Triggers: run parameters an event supplies.