OpenAPITools/openapi-generator · error · RuntimeException

Error! Codegen Parameter not yet supported in getPydanticTyp

Error message

Error! Codegen Parameter not yet supported in getPydanticType: %s

What it means

In AbstractPythonCodegen's getPydanticType(CodegenParameter, ...), a parameter is expected to have either a resolved dataType (the normal path for typed parameters) or request-body style content. A parameter with neither falls through to this RuntimeException — the generator has no pydantic type mapping for that parameter at all.

Source

Thrown at modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPythonCodegen.java:2364

            if (result == null) {
                if (!cp.isPrimitiveType) {
                    // add model prefix
                    hasModelsToImport = true;
                    modelImports.add(cp.getDataType());
                    exampleImports.add(cp.getDataType());
                    result = new PythonType(cp.getDataType());
                } else if (cp.getContent() != null) {
                    LinkedHashMap<String, CodegenMediaType> contents = cp.getContent();
                    for (String key : contents.keySet()) {
                        CodegenMediaType cmt = contents.get(key);
                        // TODO process the first one only at the moment
                        if (cmt != null)
                            // TODO: don't loop back to the deprecated getPydanticType method
                            return getPydanticType(cmt.getSchema(), modelImports, exampleImports, postponedModelImports, postponedExampleImports, moduleImports, classname);
                    }
                    throw new RuntimeException("Error! Failed to process getPydanticType when getting the content: " + cp);
                } else {
                    throw new RuntimeException("Error! Codegen Parameter not yet supported in getPydanticType: " + cp);
                }
            }

            return result;
        }

        private String finalizeType(CodegenParameter cp, PythonType pt) {
            if (!cp.required || cp.isNullable) {
                moduleImports.add(TYPING, "Optional");
                PythonType opt = new PythonType("Optional");
                opt.addTypeParam(pt);
                pt = opt;
            }

            if (!StringUtils.isEmpty(cp.description)) { // has description
                pt.annotate("description", cp.description);
            }

View on GitHub (pinned to fcec517be3)

Solutions

1. Add an explicit schema to the failing parameter, e.g. schema: { type: string }
2. Resolve or inline the parameter's $ref so it carries a real schema
3. Run a Spectral/swagger-cli validation pass — parameters without schemas are flagged before generation ever runs

Example fix

# before
parameters:
  - name: q
    in: query

# after
parameters:
  - name: q
    in: query
    schema:
      type: string

// JS: every operation parameter must carry a schema (or valid $ref to one)
for (const item of Object.values(spec.paths || {})) {
  for (const op of Object.values(item)) {
    for (const p of (op && op.parameters) || []) {
      if (!p.schema && !p.$ref) fail(`parameter '${p.name}' has no schema`);
    }
  }
}

try { generator.generate(); } catch (RuntimeException e) { if (String.valueOf(e.getMessage()).contains("Codegen Parameter not yet supported")) { /* message prints the parameter: add its missing schema */ } throw e; }

When it happens

Trigger: A query/header/path parameter with no usable schema so dataType stays unset, e.g. { name: q, in: query } with the schema block missing, or a schema whose type the mapper leaves unresolved, or a $ref that resolves to an object without a schema.

Common situations: Typos that drop the schema: block; spec converters/prototools emitting parameters without schemas; lenient OpenAPI 3.1 parsing letting incomplete parameters through to generation.

Related errors

• Error! Codegen Parameter not yet supported in getPydanticTyp
• Error! Failed to process getPydanticType when getting the co
• Please report the issue as the parameter name cannot be null
• Empty method name (operationId) not allowed
• Error! Failed to process getPydanticType when getting the co

AI-assisted analysis of OpenAPITools/openapi-generator@fcec517be3 (2026-08-22). Data as JSON: /api/errors/f254e0a5d4df64e0. Report an issue: GitHub.