Jsonschema-rs backend

[p1c2u]

Benchmarks:

• github-jsonschema-rs.prof
  • total_tt: 10.77s
  • total_calls: 19.43M
• github-jsonschema.prof
  • total_tt: 18.24s
  • total_calls: 42.47M

Result:

• jsonschema-rs backend is about 1.69x faster (~41% lower total_tt)
• and does ~23.0M fewer calls (~54% fewer).
  Where the win comes from:
• Huge reductions in Python jsonschema keyword/descend/ref paths:
  • jsonschema.validators.descend: 10.86s -> 3.22s
  • jsonschema._keywords.properties: 10.87s -> 3.22s
  • jsonschema.validators.iter_errors: 10.89s -> 3.24s
  • jsonschema._keywords.ref: 10.74s -> 3.09s
• Some costly keyword handlers disappear entirely with Rust path in this run:
  • patternProperties, oneOf (in Python jsonschema stack).
    Cost introduced by Rust path is small in profile:
• rust_adapters.iter_errors: ~0.058s
• native jsonschema_rs.Validator.validate: ~0.058s

Relates #477

[Copilot]

Pull request overview

Adds an optional jsonschema-rs-powered schema validation backend to improve performance, with environment-based selection and CI coverage to ensure both backends behave acceptably within this codebase.

Changes:

• Introduces backend selection (auto / jsonschema / jsonschema-rs) via OPENAPI_SPEC_VALIDATOR_SCHEMA_VALIDATOR_BACKEND and wires it into schema validator construction.
• Adds a jsonschema-rs adapter layer and updates CLI behavior/output for backend-specific subschema-details handling.
• Updates tests/docs/CI to support both backends and loosen assertions where error strings differ.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
openapi_spec_validator/settings.py	Adds settings field + normalization for backend selection.
openapi_spec_validator/schemas/backend/init.py	Implements backend selection logic and validator factory routing.
openapi_spec_validator/schemas/backend/jsonschema.py	Adds a small factory for the Python jsonschema backend.
openapi_spec_validator/schemas/backend/jsonschema_rs.py	Adds the Rust adapter/wrapper and validator factory.
openapi_spec_validator/schemas/init.py	Switches schema validator proxies to use backend factories and exposes backend selection.
openapi_spec_validator/main.py	Gates subschema detail printing based on backend support.
tests/integration/validation/test_exceptions.py	Makes error-message assertions backend-agnostic (substring-based).
tests/integration/test_main.py	Adjusts CLI-output assertions to handle backend differences and adds a backend-gating test.
tests/integration/test_shortcuts.py	Adds tests for env-driven backend selection and module behavior.
tests/bench/runner.py	Prints configured/effective backend in benchmark output.
docs/python.rst	Documents backend selection env var.
docs/cli.rst	Notes backend selection env var for CLI usage.
README.rst	Documents backend selection env var in performance tuning section.
.github/workflows/python-tests.yml	Runs test matrix for both jsonschema and jsonschema-rs backends.

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[p1c2u]

@copilot open a new pull request to apply changes based on the comments in this thread

[Copilot]

@p1c2u I've opened a new pull request, #480, to work on those changes. Once the pull request is ready, I'll request review from you.