0.29.1 (2026-08-30)

🚨Security

Arbitrary code generation vulnerability

Prior to this release, malicious OpenAPI documents could cause openapi-python-client to generate arbitrary code, which
would then be executed by consumers of the generated client.

If you generate code from OpenAPI documents you don't control, you should upgrade to this release as soon as possible
and validate any previously-generated code.

See the GitHub advisory for more details.

🚀 Features

• Update uv_build to 0.12 when using --meta=uv (#1473)

🐛 Fixes

• Apply PEP 639 for improved license metadata (#1459)
• update generated code to use StrEnum and -> Self (#1474)
• Remove trailing spaces in README example code (#1475)
• Stopped generating empty docstrings for models with no description

Fixed invalid Python identifiers when resolving naming conflicts

When two property or parameter names conflicted after conversion to snake_case (e.g. foo-bar and fooBar), the conflict-resolution path preserved delimiters like -, ., and spaces in the generated Python identifiers, producing invalid code which failed generation. Conflicting names now keep their original casing but have any characters which are invalid in Python identifiers stripped (e.g. foobar and fooBar).

Improve readability of error messages

Errors and warnings which include a snippet of your OpenAPI document now render that snippet as JSON, making them much easier to read.

📝Notes

Breaking changes for all custom templates

ALL custom templates are expected to break with this version as a result of the security fix.

1. The utils global has been renamed to strings
2. Most string values can no longer be rendered directly into templates,
   you must describe how the value is being used so it can be properly escaped using either a Python function or Jinja filter:
   1. strings.snake_case() / | snakecase (existing)
   2. strings.kebab_case() / | kebabcase (existing)
   3. strings.pascal_case() / | pascalcase (existing)
   4. python_identifier() (existing)
   5. class_name() (existing)
   6. strings.safe_for_docstring() / | safe_for_docstring for values which get injected into a """ docstring
   7. strings.in_f_string_literal() / | in_f_string_literal for values that go into f"" f-strings
   8. strings.in_double_quote_literal() / | in_double_quote_literal for values that go into non-f-string "" literals
   9. .as_unembedded_code() / | as_unembedded_code ONLY for PythonCode values—those that are intended to be Python code which is not embedded into any string/docstring. Examples include usages of .python_code, .get_type_string(), .get_instance_type_string(), .get_type_strings_in_union(). You should not assume these values are safe to put in docstrings, string literals, or f-string literals. Use the dedicated helpers for those.
      As always, you can check the diff of the built in templates for examples. You will also want to check generated output
      for "UntrustedString", which is how any string now requiring one of those functions will appear.

Many control characters now stripped from string literals

Out of an abundance of caution, most Unicode control characters are now stripped from string literals.
If your API uses control characters as part of const values, enums, or JSON body property names you may have issues
with this new version.

Most APIs are not expected to be affected by this change.