commanddepends

Commanddepends is a concept used in workflow automation and build orchestration to specify that the execution of one command should occur only after one or more other commands have completed successfully. It expresses a dependency relation in a directed graph of tasks, with edges from prerequisites to dependents that guide the scheduling of work.

In practice, commanddepends enables parallel execution where possible and serial execution when needed. It also provides a mechanism for failure handling: if a prerequisite fails, dependent commands are halted or marked as failed, and the overall workflow can fail fast or trigger retries and compensating actions. Dependencies can be static, defined at design time, or dynamic, determined at runtime based on results or environment.

Various tools implement this constraint with different syntax and semantics. Make uses target prerequisites to encode dependencies; modern continuous integration systems use needs or depends_on directives; workflow engines express upstream and downstream relationships that resemble commanddepends. A typical use is to declare that a deploy step depends on successful build and test steps, ensuring that downstream work only runs after all prerequisites succeed. Dependency graphs also influence scheduling decisions, allowing independent branches to run in parallel while preserving correct order for dependent steps.

Common challenges include avoiding circular dependencies, handling long-running tasks, and managing partial failures or retries. Effective use of commanddepends relies on clear modeling of task relationships, robust error propagation, and observability to diagnose which prerequisites influenced downstream outcomes.

See also: dependency graph, build system, task runner, workflow automation, continuous integration.