what is pre commit looks like and how to implement it

4 minute read

The pre-commit can find and fix common issues before changes are submitted for code review;

Code reviewers should pay attention to the architecture of a change and not worry about trivial errors like syntax error, not following code style, test missing.

How to implement pre-commit [TL;DR]

  1. write a python script(pre-commit.py) to check all the checkable files and print error messages;
    1. get all committed files;
    2. filter with exclude files;
    3. split files into .py, .js and .html;
    4. check with customize pep8, pylint, isort, jshint, jscs etc;
    5. commit continue if all check pass, else we will have more details in report file.
  2. write a shell script(pre_commit)(name should not change) which actually called by git command;
    1. active the specific env(which create by step 3);
    2. execute the real checker script.
  3. write another shell script(install_pre_commit.sh) to install pre-commit;
    1. make a independent env with virtualenv;
    2. install third libs in this env, such as pep8, pylint, isort etc(make sure they have specific version number);
    3. copy the pre_commit shell script to git directory and make it executable.

Actually you should not reinvent the wheel

  1. pip install pre-commit;
  2. pre-commit install;
  3. create file .pre-commit-hooks.yaml at the root of your repo and configure your hooks.

the simplest hooks configuration like this:

- repo: git://github.com/pre-commit/pre-commit-hooks
  sha: v0.4.2
  - id: trailing-whitespace

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