panproto 0.42.0

Automatic schema migration and version control for 51 schema languages and 248 programming languages

panproto

Native Python bindings for panproto. Define schemas, detect breaking changes, and automatically convert data between schema versions. Supports 51 schema languages (OpenAPI, ATProto, Protobuf, JSON Schema, and more) and can parse source code in 250 programming languages via tree-sitter.

Built with PyO3 for direct access to the Rust engine (no WASM, no subprocess). Requires Python 3.13+.

Installation

pip install panproto

Quick start

import panproto as pp

# Build two versions of a schema
builder = pp.SchemaBuilder("atproto")
builder.vertex("post", "record", nsid="app.bsky.feed.post")
builder.vertex("post:body", "object")
builder.vertex("post:body.text", "string")
builder.edge("post", "post:body", "record-schema")
builder.edge("post:body", "post:body.text", "prop", name="text")
builder.constraint("post:body.text", "maxLength", "3000")
old_schema = builder.build()

# ... build new_schema similarly, with renamed fields ...

# Check whether the change is breaking
report = pp.diff_and_classify(old_schema, new_schema, protocol)
print(report.compatible)        # True or False
print(report.report_text())     # human-readable summary

# Auto-generate a bidirectional converter.
# Returns (lens, alignment_quality, coerce_proposals); the last is empty
# unless `stringency="exploratory"` is passed.
lens, quality, coerce_proposals = pp.auto_generate_lens(old_schema, new_schema, protocol)
view, complement = lens.get(instance)
restored = lens.put(view, complement)

# Parse and emit data in any supported format
io = pp.IoRegistry()
schema = io.parse_schema("json-schema", json_schema_str)
output = io.emit_schema("json-schema", schema)

# Version control
repo = pp.VcsRepository.init("/path/to/repo")
repo.add(schema)
repo.commit("add post schema", "your-name")
repo.branch("feature")
repo.merge("feature", "your-name")

API overview

Schema and protocols

Function / Class	What it does
list_builtin_protocols()	List all 76+ built-in protocol names.
get_builtin_protocol(name)	Load a protocol definition by name.
define_protocol(...)	Define a custom protocol.
SchemaBuilder(protocol)	Build schemas with vertex(), edge(), constraint(), then build().
Schema	An immutable schema with vertex, edge, and constraint accessors.
Protocol	A schema language definition with edge rules and feature flags.

Breaking change detection

Function / Class	What it does
diff_schemas(old, new)	Compute a structural diff between two schemas.
diff_and_classify(old, new, protocol)	Diff and classify changes as breaking or non-breaking.
SchemaDiff	The diff result: added, removed, and changed elements.
CompatReport	Compatibility report with details on each breaking change.

Migration and lenses

Function / Class	What it does
auto_generate_lens(src, tgt, protocol)	Generate a bidirectional converter between two schemas.
Lens	A converter with get(instance) (forward) and put(view, complement) (backward).
Complement	The data dropped during forward conversion, needed for lossless backward conversion.
MigrationBuilder	Build a migration by specifying vertex and edge mappings.
compile_migration(src, tgt, migration)	Compile a migration for application.
compose_migrations(m1, m2)	Chain two migrations into one.
check_existence(src, tgt, migration, protocol)	Validate that a migration is well-formed.

Data I/O

Function / Class	What it does
Instance	A data record with from_json(), to_json(), and validate().
IoRegistry	Parse and emit schemas and data in any of the 76+ supported formats.

Theory engine

Function / Class	What it does
create_theory(name, sorts, ops, eqs)	Define a custom schema language theory.
Theory	A theory with sort, operation, and equation accessors.
colimit_theories(t1, t2, shared)	Combine two theories into one.
check_morphism(morphism, domain, codomain)	Validate a structure-preserving map between theories.
Model	A concrete model of a theory.

Version control

Function / Class	What it does
VcsRepository.init(path)	Initialize a new panproto repository.
VcsRepository.open(path)	Open an existing repository.
repo.add(schema)	Stage a schema for commit.
repo.commit(message, author)	Create a new commit.
repo.branch(name)	Create a branch.
repo.merge(branch, author)	Merge a branch into the current one.

Documentation

Full documentation at panproto.dev.

License

MIT