eredu-checkpoint

eredu-checkpoint defines backend-neutral checkpoint contracts for Eredu. It describes stored tensor encodings, logical tensor recipes, checkpoint schemas, selection plans, and encoded tensor leases without allocating backend tensors or executing accelerator operations.

The crate includes portable SafeTensors and GGUF validation, stable filesystem-backed artifact fingerprinting, and storage interfaces. Its canonical SafeTensors shard discovery requires every index mapping to exactly match the referenced shard headers and confines resolved payloads to the checkpoint access root. Neutral stores use the same canonical index parsing and path admission, but validate and buffer a payload shard only when a caller requests one. On first access, the complete opened shard header must exactly match every index mapping for that shard; unopened remote-only shards remain unread. Artifact inspection and conversion tooling use strict discovery. Architecture crates use these types to declare checkpoint intent; backend implementations decide how selected values are materialized and where they reside.

Prepared SafeTensors/GGUF constructors and restricted source views preserve a single physical source cache while exposing exact architecture-selected roles. Restricted views fail closed for metadata, provenance, and lease requests to keys outside their explicit contract.

PreparedCheckpointSource binds the exact admitted catalog, shard identities, provenance, selections, and bounded lease geometry to the source used for later payload reads. Preparation records each admitted file's identity and inspects only its metadata and header; it does not retain a descriptor per shard. The snapshot includes canonical path and Unix change time (plus device and inode); targets whose standard metadata API exposes no equivalent change counter retain the strongest available length and timestamp metadata. After recipe and destination preflight, only a requested shard is reopened and validated, then its exact selected ranges are admitted by matching bounded reads. Immutable cached bytes protect published leases from later path or in-place substitution.

Most applications should use eredu. Use this crate directly when implementing checkpoint tooling, an architecture integration, or a concrete backend.

License

Licensed under either Apache-2.0 or MIT.