Dependencies and partial reruns

Each step declares a ProcessStepDependencies contract containing:

• external source_refs;

• processing_reads; and

• processing_writes.

Many contracts are derived from ProcessStepDescriber.arguments dependency roles. Steps override the contract only for relationships the schema cannot express. Wildcards are conservative fallbacks, not substitutes for dependencies that can be known exactly.

Full execution

A full run executes every graph node in topological order. Use it for the first run, after pipeline configuration changes, or whenever the changed input scope is uncertain.

Selected execution

The local runner can execute selected step identifiers against caller-supplied ProcessingData. The caller is responsible for providing valid prerequisites. This is mainly useful for testing and controlled interactive work.

Partial execution

The runtime service can reuse a previous result:

1. Identify steps that read a changed source or processing path.

2. Expand the dirty set to all downstream descendants.

3. Copy the previous ProcessingData snapshot.

4. Execute only the dirty subgraph.

auto mode attempts this path and falls back to a full run when partial execution fails. A dry run previews the selected steps without mutating session state.

Exact contracts matter: an undeclared read can incorrectly reuse stale data, while an overly broad wildcard discards valid reuse. Extension authors should assert all three dependency sets in focused tests.