FAQ

How does it work?

Tach works by analyzing the imports in your Python modules. When you define dependencies in your project-level tach.yml, running tach check will verify that the imports in your modules match your expected dependencies.

What is a module?

A 'module' is a Python module with dependencies configured in tach.yml. A module can be a python file or a directory with an __init__.py. The module is identified by its import path from your project root (e.g. a.b for <root>/a/b.py), and its dependencies are listed in the depends_on key containing module paths in the same format.

Are conditional imports checked?

Tach will check all imports in your source files, including those which are called conditionally. The only exceptions are imports made within TYPE_CHECKING conditional blocks. If you want to disable checks for these imports, you can add ignore_type_checking_imports: true to your tach.yml.

Can you catch dynamic references?

Since Tach uses the AST to find imports and public members, dynamic imports (e.g. using a string path) and dynamic names (e.g. using setattr, locals, globals) are not supported. If these usages cause Tach to report incorrect errors, the ignore directive should be sufficient to reach a passing state.

How can I make a feature request or file a bug?

This project uses GitHub Issues to track bugs and feature requests. Search the existing issues before filing new issues to avoid duplicates. File your bug or feature request as a new Issue.

How can I get help?

For help and questions, join the Discord!

How can I report a security issue?

Do not report security vulnerabilities through public GitHub issues. Instead, please send a DM to caelean or nashsando on Discord. You can also email us at caelean@gauge.sh or evan@gauge.sh. If the issue is significant, we will consider paying a bounty.

What information does Tach track?

Tach tracks anonymized usage and error report statistics; we ascribe to Posthog's approach as detailed here. If you would like to opt out of sending anonymized info, you can set disable_logging to true in your tach.yml.