precog 0.0.2

Installation

To install from PyPI, run pip install precog. To install the githook, run precog. This will try to write to your pre-commit file (.git/hooks/pre-commit), and will abort if it already exists, so move or remove it if you want to use precog.

Usage

Once you have precog installed, your commits will be checked that they conform. By default it will abort a commit if any of flake8, isort or eslint do not exit cleanly, but will make no effort to fix any problems. The pre-commit file contains the default values for the options, but you can override the behaviour with environment variables when committing, or if you can edit the defaults in the pre-commit file.

The ISORT_FORCE option

This one is a bit mad. Because isort knows how to fix the problems it finds (while flake8 and eslint do not), rather than complaining at you, this option tells precog to tweak your changed files to conform to the isort checking. Though this is a bit scary, so is disabled by default.

In the case where all of a file is staged for commit, this is fairly straight-forward: precog will just run isort on the file and then re-add it to include those changes in the commit. But if only part of file is staged, then we don’t want to add the whole file. So we make use of the -k option to git stash to stash only the unstaged changes. We then run isort, add the file, then pop the stash.

There are almost certainly edge-cases in this, and if it mucks up your commit, then I am sorry. Out of your sadness, a PR/issue can rise to make it not happen again.

Integration with eslint

To lint your JavaScript, precog will invoke eslint on any changed .js files. Because it is not a Python dependency, installing precog makes no attempt to install eslint, but will try to find it at node_modules/.bin/eslint. If it doesn’t find it, it will assume it is installed globally. You can set the ESLINT_PATH environment variable if this doesn’t find it - if so you may want to set it as a default in your pre-commit file.