hashtree-collection

Immutable content-addressed collections for hashtree.

This Rust crate provides the core collection pieces that hashtree-nostr and other Rust crates can share today:

• canonical by-id roots
• named derived key indexes
• named derived search indexes
• optional schema defaults, normalization, validation, and migration hooks
• incremental put / delete updates
• full rebuilds and explicit reindexing from owned item snapshots
• directory-root read/write helpers
• federated search across many collection sources
• shared search roots for multiple named views
• contextual derived search entries for related entities

reindex is the public "rebuild everything from canonical items" entrypoint. It is useful when you add a new derived index or change derivation rules, but it still requires caller-supplied item snapshots and their CIDs. Collection roots alone are not enough to regenerate new indexes.

The Rust crate now covers the same core lifecycle as the TypeScript @hashtree/collection package: collection roots, derived indexes, schema hooks, and federated search helpers. It still stays focused on immutable collection/index mechanics rather than trying to become a general-purpose database layer.

Published collection roots can include a reserved .collection-manifest.json file for small declarative metadata that peers can inspect directly. The JSON shape matches the TypeScript package and currently includes:

• schemaVersion
• publishedSchema.itemFormat
• publishedSchema.projectionFormat
• optional publishedSchema.schemaRef

Index names are expected to be reasonably self-descriptive, so this metadata does not add a separate per-index description layer by default.

Part of hashtree.