idiolect-migrate

Source: crates/idiolect-migrate/

This crate is publish = false and is not on docs.rs. The authoritative reference is the source above plus the rustdoc built locally with cargo doc -p idiolect-migrate --open.

Schema-diff classification plus lens-based record migration. Thin typed façade over panproto-check (for diff classification) and idiolect-lens (for record translation).

Because the crate is publish = false, depend via git or path:

[dependencies]
idiolect-migrate = { git = "https://github.com/idiolect-dev/idiolect", tag = "v0.8.0" }

Public surface

The crate exposes:

classify(src, tgt) — runs the panproto diff and returns a CompatReport distinguishing compatible from breaking changes.
plan_auto(src, tgt, hints) — for breaking diffs that are covered by shipped migration recipes, returns a MigrationPlan carrying source / target schema hashes plus a lens body the caller can publish. For breaking diffs that resist automation, returns Err(PlannerError::NotAutoDerivable) listing the offending changes.
migrate_record(lens, source_record, schema_loader) — wraps idiolect_lens::apply_lens for the one-shot case.
MigrationPlan — the typed plan struct.
MigrateError, MigrateResult, PlannerError — the error types.
Re-exported CompatReport and SchemaDiff from panproto-check for convenience.

Migration shapes

Diff	Behavior
Non-breaking (added optional, added vertex, added edge)	`classify` returns `compatible = true`; no plan is needed.
Auto-derivable breaking (removed optional, renamed vertex via hint)	`plan_auto` returns a `MigrationPlan` with a protolens-chain body.
Non-auto breaking (removed required, changed required type, added required without default)	`plan_auto` returns `NotAutoDerivable`. The caller writes the lens by hand.

Why this is a separate crate from idiolect-lens

Two reasons:

The migration-shaped API (classify-then-plan-then-migrate) is a different shape than the runtime API (apply_lens plus resolvers).
idiolect-migrate depends on panproto-check, which is a heavier dep than the lens runtime itself. Keeping it separate keeps the runtime crate's compile-time small.

Scope

The crate owns no runtime state. It is a thin façade; the runtime cost of a migration equals the cost of one apply_lens per record.