CPACS Schema Tool

cpacs-schema-tool is the shared formatter, checker, linter, and explicit migration utility for CPACS XML Schema files. It is intended for the official CPACS repository, TiGL, and project-internal CPACS schema instances.

The package ships the CPACS Standard Schema Rules. Projects use those rules without copying a configuration file and may layer small, explicit overrides on top when necessary.

Commands

cpacs-schema format schema/cpacs_schema.xsd --in-place
cpacs-schema check schema/cpacs_schema.xsd
cpacs-schema lint schema/cpacs_schema.xsd
cpacs-schema rename-types schema/cpacs_schema.xsd
cpacs-schema prune-unused schema/cpacs_schema.xsd

The commands deliberately distinguish representation-preserving formatting from schema-changing migrations:

• format normalizes ordering, attributes, whitespace, and redundant occurrence defaults.
• check verifies canonical formatting and XSD compilation.
• lint checks CPACS conventions, references, reachability, prefixes, and XSD validity.
• rename-types produces a dry-run plan unless --apply is supplied.
• prune-unused produces a dry-run plan unless --apply is supplied.

Writes are atomic. Existing files are overwritten only with --in-place; an optional --backup creates <schema>.bak.

Installation

Development installation:

python -m pip install -e ".[dev]"
python -m pytest

Using Conda:

conda create -n cpacs-schema -c conda-forge python=3.10 pip git
conda activate cpacs-schema
python -m pip install "cpacs-schema-tool @ git+https://github.com/DLR-SL/cpacs-schema-tool.git@v0.1.1"
cpacs-schema --version

Using Pixi:

pixi run check

Until the package is published on PyPI, a consumer can pin the released Git tag:

[pypi-dependencies]
cpacs-schema-tool = {
    git = "https://github.com/DLR-SL/cpacs-schema-tool.git",
    tag = "v0.1.1"
}

Built-in policy

Running a command without --rules uses the bundled standard policy:

cpacs-schema lint schema/cpacs_schema.xsd

The bundled policy defines, among other things:

• the cpacs root element and cpacsType root type;
• canonical top-level declaration and attribute ordering;
• CPACS base-type ordering;
• type naming rules;
• reference and reachability checks;
• XSD/XLink prefix conventions;
• severities for diagnostics CPACS001 through CPACS011.

The policy has its own metadata:

[policy]
name = "CPACS Standard Schema Rules"
version = "1.0"

Partial project overrides

--rules applies a partial TOML file over the bundled CPACS defaults. The option may be repeated; later files take precedence.

cpacs-schema lint project_schema.xsd \
    --rules project_schema_overrides.toml

Example:

[reachability]
keep_add = ["projectMetadataType"]

[naming.types]
exceptions_add = ["LegacyProjectType"]

[rules.CPACS009]
severity = "error"

Tables are merged recursively. Scalar values and ordinary arrays replace the corresponding defaults. For array-valued settings, _add and _remove modify the existing standard list without copying it:

[reachability]
keep_add = ["publicProjectType"]
keep_remove = ["obsoletePublicType"]

A complete independent policy can be supplied with --replace-rules. It must contain every required table and is mutually exclusive with --rules.

cpacs-schema lint another_schema.xsd \
    --replace-rules complete_policy.toml

The effective merged policy can be inspected reproducibly:

cpacs-schema lint schema.xsd --print-effective-rules

Policy and tool versioning

Consumer repositories should pin a released tool version or full Git commit. Changes that alter canonical formatting or turn formerly accepted constructs into errors must be documented in the changelog. Explicit rename mappings are best supplied as release-specific override files rather than accumulated in the permanent standard policy.

License

Apache License 2.0. See LICENSE and NOTICE.