Module run_graph 

Workspace-wide scheduler that turns a validated TaskGraph into a sequence of run_task calls subject to the workspace’s concurrency caps.

The public surface is run_graph: a single async function that walks the graph, admits ready tasks in canonical (ProjectName, TaskName) order subject to the workspace’s global cap (EXEC-004) and per-tag caps (EXEC-005), and threads each completed task’s (stdout, stderr) content hashes into every downstream call so cache-key derivation has the predecessor-stream contribution it needs (CACHE-007 / DAG-017).

The loop is built on futures::stream::FuturesUnordered. Each pushed future borrows ctx and owns a snapshot of the current predecessor map; awaiting completion returns the (TaskId, Result<CompletedRecord, RunTaskError>) pair so the main body can re-acquire its own mutable borrows. The outcomes map stores the broader [RunOutcome] sum (Completed wraps the record; Skipped lands once the cascade work in a follow-up commit wires the variant).

Mutex composition (EXEC-006 condition 3, EXEC-007) is delivered through a lookup-then-spawn pipeline: each admitted task first runs [cache_lookup_phase]; on a hit the scheduler records the outcome immediately, and on a miss it consults its live mutex hold set before acquiring the mutex and driving [run_fresh]. Cache hits never touch the hold set per MUTEX-007. A task whose mutex is incompatible after lookup is returned to ready per MUTEX-005, its slot is released, and the next admission round re-evaluates.

Cancellation (EXEC-012..015), the formal Skipped state and its typed diagnostics (EXEC-011), runtime cycle / overlap detection (EXEC-019..020), and live-mode output presentation (EXEC-016) are all wired through this module alongside the lookup-then-spawn pipeline.

Structs

RunGraphOutcome

Outcome of a single run_graph invocation.

Enums

RunGraphError

Top-level error raised by run_graph.

RuntimeInvariantViolation

A workspace-level invariant the scheduler detected at runtime.

Functions

run_graph

Run every task in the validated graph subject to the workspace’s concurrency caps and the mutex compatibility rules of EXEC-006 condition 3 + EXEC-007.