Python dependency checker (with support for zope zcml files and doctests)
Latest commit f22c03a Dec 16, 2017 @gforcada gforcada Merge pull request #63 from reinout/gforcada-db-package
Database and Package



Checks which imports are done and compares them to what's in and warn when discovering missing or unneeded dependencies.

What it does

z3c.dependencychecker reports on:

  • Unused imports: pyflakes is another tool that does this (and that also reports on missing variables inside the files).

  • Missing (test) requirements: imports without a corresponding requirement in the There might be false alarms, but at least you've got a (hopefully short) list of items to check.

    Watch out for packages that have a different name than how they're imported. For instance a requirement on pydns which is used as import DNS in your code: pydns and DNS lead to separate "missing requirements: DNS" and "unneeded requirements: pydns" warnings.

  • Unneeded (test) requirements: requirements in your that aren't imported anywhere in your code. You might need them because not everything needs to be imported. It at least gives you a much smaller list to check by hand.

  • Requirements that should be test-only: if something is only imported in a test file, it shouldn't be in the generic defaults. So you get a separate list of requirements that should be moved from the regular to the test requirements.

It checks the following locations:

  • Python files for regular imports.
  • Zcml files for package="some.thing" attributes. It also supports Plone's generic setup files.
  • Python files, .txt and .rst files for imports in doctests.

Note on running the tests

The tests are quite sensitive to other python packages being available. If the tests do not run, first wrap the buildout in a virtualenv to make double sure there are no interfering packages. Or make sure you use a clean (system) python.


z3c.dependencychecker is a different application/packaging of zope's importchecker utility. It has been used in quite some projects, I grabbed a copy from lovely.recipe's checkout.

Source code, forking and reporting bugs

The source code can be found on github:

You can fork and fix it from there. And you can add issues and feature requests in the github issue tracker.

Every time you commit something, bin/code-analysis is automatically run. Pay attention to the output and fix the problems that are reported. Or fix the setup so that inappropriate reports are filtered out.