How to Patch a Package in Vendor, Yet Allow its Updates

While working with legacy code upgrades, we often need to fix a line or two in 3rd party package in /vendor.

You can fork it, but by that, you take manual responsibility for all the package updates. You can copy a package locally, which is faster, but disables package updates.

Or... you can use "composer patches"?

I'm currently working on one Nette project as a cleaning lady. After making code nice & shiny clean, we'll move from Nette 2.4 to Nette 3.0. During the cleaning process, we got into one delicate issue I'd love to share with you.


We used inject properties:

<?php

abstract class AbstractSomePresenter
{
    /**
     * @inject
     * @var SomeDependency
     */
    public $someDependency;
}

But since PHP 7.4, we could drop the @var annotation:

<?php

abstract class AbstractSomePresenter
{
    /**
     * @inject
     */
    public SomeDependency $someDependency;
}

But... this doesn't work in Nette 2.4. Aww.


We tried to add this feature by replacing native InjectExtension with our own. But native extension is statically hardcoded, so there was no way to replace it.

What else we can do? We looked at GitHub for a commit that added this feature somewhere between Nette 2.4 and 3.0 (with git blame GitHub feature and look at specific lines).

We were lucky. It was just 2 lines that added this feature!

How to Change 2 Lines of code in /vendor?

We needed the same commit in our codebase with Nette 2.4.

How can we do that?

❌

These options are slow or will keep the code changed only on your local machine = your composer install would suck a long time.


Is there some automated way with all the benefits and almost zero maintenance?

✅

Patching For Dummies

Idea behind composer patches is great, but the user experience with making the patch not so much. It's classic pixel coding - you have to edit the patch file the one slash or dot char. If you do it wrong, or the whole process collides with "fatal error". That's why there is over 10 comments under Czech post by Tomas Pilar, asking about the pixel coding.

I don't want developers to be frustrated over pixel coding. I want developers to play and explore their abilities to their limits.

We made a Symplify package that adds UX layer that handles the tedious maintenance for you.

4 Steps to Generate Your First Patch

1. Install Packages

composer require cweagans/composer-patches symplify/vendor-patches --dev

2. Create a Copy of /vendor file you Want To Change with *.old Suffix

For example, if you edit:

vendor/nette/di/src/DI/Extensions/InjectExtension.php

The copied file would be:

vendor/nette/di/src/DI/Extensions/InjectExtension.php.old

3. Open the Original file and Change it

         if (DI\Helpers::parseAnnotation($rp, 'inject') !== null) {
-           if ($type = DI\Helpers::parseAnnotation($rp, 'var')) {
+           if ($type = \Amateri\Reflection\Helper\StaticReflectionHelper::getPropertyType($rp)) {
+           } elseif ($type = DI\Helpers::parseAnnotation($rp, 'var')) {
               $type = Reflection::expandClassName($type, Reflection::getPropertyDeclaringClass($rp));

Only *.php file is loaded, not the *.php.old one. This way, you can be sure the new code is working before you generate patches.

4. Run generate command to Create Patch File and Register it

vendor/bin/vendor-patches generate

The Symplify tool will generate patch files for all files created this way in /patches directory:

/patches/nette-di-di-extensions-injectextension.php.patch

The patch path is created from the original file path, so the patch name is always unique.

Also, the configuration for cweagans/composer-patches is added your composer.json:

{
    "extra": {
        "patches": {
            "nette/di": [
                "patches/nette_di_di_extensions_injectextension.patch"
            ]
        }
    }
}

That's it!


Now all you need to do is run composer:

composer install

And your patches are applied to your code!


Happy coding!



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