OpenAPITools/openapi-generator · error · RuntimeException

Error! Codegen Property not yet supported in getPydanticType

Error message

Error! Codegen Property not yet supported in getPydanticType: {cp}

What it means

In AbstractPythonPydanticV1Codegen's getPydanticType for properties, every CodegenProperty must reduce to a Python type through the handled branches (primitives, containers, enums, model refs). A property matching no branch falls through to this RuntimeException — the pydantic-v1 mapper has no type mapping for that property shape yet.

Source

Thrown at modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPythonPydanticV1Codegen.java:1596

                    if (circularImports.get(cp.dataType).contains(classname)) {
                        hasModelsToImport = true;
                        postponedModelImports.add(cp.dataType);
                        postponedExampleImports.add(cp.dataType);
                        // cp.dataType import map of set contains this model (classname), don't import
                        LOGGER.debug("Skipped importing {} in {} due to circular import.", cp.dataType, classname);
                    } else {
                        // not circular import, so ok to import it
                        hasModelsToImport = true;
                        modelImports.add(cp.dataType);
                        exampleImports.add(cp.dataType);
                    }
                } else {
                    LOGGER.error("Failed to look up {} from the imports (map of set) of models.", cp.dataType);
                }
            }
            return cp.dataType;
        } else {
            throw new RuntimeException("Error! Codegen Property not yet supported in getPydanticType: " + cp);
        }
    }

    public void setMapNumberTo(String mapNumberTo) {
        if ("Union[StrictFloat, StrictInt]".equals(mapNumberTo)
                || "StrictFloat".equals(mapNumberTo)
                || "float".equals(mapNumberTo)) {
            this.mapNumberTo = mapNumberTo;
        } else {
            throw new IllegalArgumentException("mapNumberTo value must be Union[StrictFloat, StrictInt], StrictStr or float");
        }
    }

    public String toEnumVariableName(String name, String datatype) {
        name = name.replace(".", "_DOT_");

        if ("int".equals(datatype)) {
            return "NUMBER_" + name.replace("-", "MINUS_");

View on GitHub (pinned to fcec517be3)

Solutions

1. Find the failing property from the CodegenProperty dump and restructure it — hoist composed inner schemas into named components
2. Upgrade openapi-generator to the latest release with improved pydantic-v1 coverage
3. Still failing, open a GitHub issue with the model snippet — the exception says the case is not yet supported

Example fix

# before
metadata:
  type: object
  additionalProperties:
    oneOf:
      - type: string
      - type: boolean

# after
metadata:
  type: object
  additionalProperties:
    $ref: '#/components/schemas/MetadataValue'

try {
    new DefaultGenerator().opts(clientOptInput).generate();
} catch (RuntimeException e) {
    if (e.getMessage() != null && e.getMessage().contains("not yet supported in getPydanticType")) {
        // CodegenProperty dump in the message names the failing property: hoist/simplify it
        throw new BuildFailure("Unsupported pydantic-v1 property: " + e.getMessage(), e);
    }
    throw e;
}

When it happens

Trigger: Generating -g python-pydantic-v1 when a model property uses a combination the mapper does not cover — e.g. maps of composed schemas or other nested constructs, depending on release. The message dumps the full CodegenProperty, identifying the offender.

Common situations: Complex enterprise specs with unusual nesting; running a newer spec against an older pinned generator; migrating from -g python to -g python-pydantic-v1 and hitting v1-specific gaps.

Related errors

• Error! Codegen Property not yet supported in getPydanticType
• property %s in model %s has invalid generated Python field n
• recursionLimit must be an integer, e.g. 2000.
• Could not process model '{name}'.Please make sure that your
• Could not process operation: Tag: {tag} Operation: {oper

AI-assisted analysis of OpenAPITools/openapi-generator@fcec517be3 (2026-08-22). Data as JSON: /api/errors/7a1f3e6ccc915ec7. Report an issue: GitHub.