panproto 0.42.2

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

panproto

Python bindings for panproto, a schematic version-control system that treats every supported schema language (around 50, including ATProto, OpenAPI, AsyncAPI, Avro, Protobuf, JSON Schema, and Kubernetes CRDs) as views over a single graph format.

The bindings are built with PyO3 against the Rust core directly: no WASM runtime, no subprocess, no shelling out. The full panproto surface is available from Python, including the schema/migration/lens/VCS pipelines and the tree-sitter-driven parser for ~250 programming languages.

Status

panproto is pre-1.0. The 0.x series carries arbitrary breaking changes between minor versions; the panproto package version tracks the workspace version on every release. Python 3.13+ is required (the wheels are abi3 and forward-compatible across newer Python releases).

Installation

pip install panproto

Wheels are published on PyPI for Linux x86_64/aarch64, macOS arm64+x86_64, and Windows x86_64. No Rust toolchain is required to install.

Synopsis

import panproto

# Pick a built-in protocol, or define your own with `Protocol.from_theories`.
atproto = panproto.get_builtin_protocol("atproto")

# Build a schema using the fluent builder.
v1 = atproto.schema()
v1.vertex("post", "record", "app.bsky.feed.post")
v1.vertex("post:body", "object")
v1.vertex("post:body.text", "string")
v1.edge("post", "post:body", "record-schema")
v1.edge("post:body", "post:body.text", "prop", "text")
v1.constraint("post:body.text", "maxLength", "3000")
schema_v1 = v1.build()

# (build schema_v2 the same way, with the field renamed to `content` ...)

# Detect breaking changes.
report = panproto.diff_and_classify(schema_v1, schema_v2, atproto)
print(report.compatible)        # True or False
print(report.report_text())     # human-readable summary

# Auto-generate a bidirectional converter.
lens, quality, _ = panproto.auto_generate_lens(schema_v1, schema_v2, atproto)
view, complement = lens.get(instance)
restored = lens.put(view, complement)

# Version-control schemas.
repo = panproto.Repository.init("/path/to/repo")
repo.add(schema_v1)
repo.commit("initial schema")
repo.branch("feature")
repo.merge("feature")

API overview

Module / class	Purpose
Schema, SchemaBuilder	Fluent schema construction; Schema.validate(protocol) checks rules.
Protocol	Schema-language definition. Protocol.from_theories(...) builds one from a Theory.
get_builtin_protocol(name)	Load any of the ~50 builtin protocols by name.
define_protocol(spec)	Define a custom protocol from a dict.
Theory, create_theory	GAT-level theory construction (sorts, ops, equations, directed_eqs).
diff_schemas, diff_and_classify	Structural diff and breaking-change classification.
auto_generate_lens	Generate a bidirectional Lens from two schemas.
Lens	get(instance) -> (view, complement), put(view, complement) -> instance.
MigrationBuilder, compile_migration, compose_migrations	Hand-rolled migration construction.
Instance, IoRegistry	Parse/emit data across the 50+ supported formats.
Repository	Filesystem-backed VCS: init, commit, branch, merge, log, blame, bisect, stash, tag, plus data versioning.
AstParserRegistry, parse_source_file, ParseEmitLens	Full-AST parsing across ~250 languages via tree-sitter.
Expr, parse_expr, pretty_print_expr	Embedded expression language.

Performance notes

• The _native extension talks to the Rust core through PyO3's zero-copy pyclass slabs. Schemas, theories, and lenses are reference-counted Rust objects on the Python side; mutations go through dedicated builder types (SchemaBuilder, MigrationBuilder) that consume on build(), so you can't accidentally observe partial state.
• Cross-thread sharing of these objects requires the GIL; for parallel work, fan out at the data layer (e.g. parallelise lens.get calls with concurrent.futures) and keep the schema/lens objects per worker.
• Wheel-load cost is one-time; the import sets up the protocol registry lazily so cold-start is fast.

Contributing

Source: bindings/python. Issues and pull requests at github.com/panproto/panproto/issues.

The native extension lives at crates/panproto-py on the Rust side; bindings/python/src/panproto/__init__.py is the pure-Python re-export layer that maturin ships alongside the compiled extension.

License

MIT © 2026 Aaron Steven White.