bugfix: honor configured OpenAPI Generator version across generation pipeline

[bsayli]

Describe the bug

The configured openapi-generator.version property was not consistently honored across the full client generation pipeline.

While consumers could override the OpenAPI Generator plugin version, other generation stages could still resolve a different generator version through transitive dependency management or implicit artifact resolution.

This created a mixed runtime where:

• openapi-generator-maven-plugin
• extracted upstream templates (model.mustache)
• plugin runtime dependencies (openapi-generator-core, openapi-generator)
• internal generator execution

could silently diverge.

As a result, overriding openapi-generator.version in consumer projects did not guarantee deterministic generator alignment.

The issue became observable when testing custom OpenAPI Generator versions against the openapi-generics-java-codegen-parent setup.

Steps to reproduce

1. Create a consumer project using openapi-generics-java-codegen-parent
2. Override:

<openapi-generator.version>...</openapi-generator.version>

3. Run:

mvn clean generate-sources

4. Observe that:

• plugin execution version,
• extracted upstream templates,
• and generator runtime dependencies

are not guaranteed to resolve to the same OpenAPI Generator version.

Expected behavior

The configured openapi-generator.version property should act as the single authoritative version source across the entire generation lifecycle.

The following components must always resolve to the exact same version:

• openapi-generator-maven-plugin
• openapi-generator
• openapi-generator-core
• extracted upstream templates

This ensures deterministic and reproducible generation behavior for all consumers.

Affected area

• generator version alignment
• build orchestration
• advanced generator customization

Environment

No response

Additional context

Root cause was implicit version resolution through dependency management combined with partial plugin-level version overrides.

The fix explicitly wires ${openapi-generator.version} into:

• template extraction artifacts
• plugin runtime dependencies
• generator plugin version

This restores deterministic version alignment across the entire generation pipeline.

Fixed on main and currently available in 1.0.3-SNAPSHOT.
Planned for the next public release.

Implementation reference:
e58466a