How to Delegate Code Reviews to CI

This post was updated at December 2020 with fresh know-how.
What is new?

The Bitbucket was dropped, as unused services and the demo repository is not maintained. The Travis was dropped, as it does not support open-source anymore and for private projects are better alternatives.


Are you doing code reviews? No? Yes?

In both cases, you won't have too. Just add a couple of YAML lines to your CI.

I'm very grateful that Rector is getting traction lately. More and more PHP developers save dozens of hours by running simple CLI commands on their codebases.


It's a lot. But you want more laziness, right?


Rector can do much more without you even running it.

What do you Review in Code?

If you do code-review, what do you mostly do?

  1. Look for patterns, explain them, report them everywhere or just somewhere and hope the other person will fix them all.

  2. Discuss the design and why and what should be done about it.

Well, the 2nd cannot be automated, unless you're able to put it in clear step-by-step, e.g SOLID laws in procedural code. So you still have to do that, sorry.

Dead Fat Code

But 1st step can be easily automated. How? Well, let's take a dead code for example. In the last project I've helped to improve with Rector, there were 2 years of dead-code piled up. A dead that you have to:

So many human-hours wasted. In the end, we removed over 12 % of "dead fat code". Wouldn't it be better if that fat would never be got it?

Add Rector in CI in 3 Steps

  1. Install Rector
composer require rector/rector --dev
  1. Create rector.php config just for code-reviews
use Rector\Set\ValueObject\SetList;
use Rector\Config\RectorConfig;

return function (RectorConfig $rectorConfig): void {
    $rectorConfig->import(SetList::DEAD_CODE);
};
  1. And add to your CI bash
vendor/bin/rector process src --dry-run

How to add Rector CI to your Favorite CI?

I've prepared a demo with PHP code and a testing pipeline for all widely used CI services.


There you'll find all the configuration you need to let your CI do code-reviews.

1. GitHub Actions


Repository

# .github/workflows/php.yml
name: Rector Code Review

on: [push]

jobs:

    build:
        runs-on: ubuntu-latest

        steps:
            - uses: actions/checkout@v1

            -
                name: Validate composer.json and composer.lock
                run: composer validate

            -
                name: Install dependencies
                run: composer install --no-progress --no-suggest

            -
                name: Code Review
                run: ./vendor/bin/rector process --dry-run

2. Gitlab CI

# .gitlab-ci.yml
# inspired from https://docs.gitlab.com/ee/ci/examples/php.html

# see https://github.com/RobBrazier/docker-php-composer
image: robbrazier/php:7.2

before_script:
    # install composer dependencies for all stages
    - composer install --prefer-dist --no-ansi --no-interaction --no-progress

stages:
    - test

tests:
    stage: test
    script:
        - vendor/bin/phpunit

code-review:
    stage: test
    script:
        - vendor/bin/rector process --dry-run

What sets to Start With?

Here are my favorite sets I apply first:

use Rector\Nette\Set\NetteSetList;
use Rector\Set\ValueObject\SetList;
use Rector\Config\RectorConfig;

return function (RectorConfig $rectorConfig): void {
    $rectorConfig->import(SetList::CODING_STYLE);
    $rectorConfig->import(SetList::CODE_QUALITY);
    $rectorConfig->import(SetList::DEAD_CODE);
    $rectorConfig->import(NetteSetList::NETTE_UTILS_CODE_QUALITY);
};

But you don't have to stop there. Pick any of 100+ sets that Rector provides.



That's it!

Oh... one more thing. You don't have to resolve all the Rector reported flaws manually, just remove the --dry-run option and run it locally before pushing:

vendor/bin/rector process src

Enjoy your coffee!



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