Feature: Add command to generate patches

[andyexeter]

It'd be great if there was a way to create patches within this plugin.

There's an NPM package called patch-package which does this in the NPM/Node ecosystem. The way it works is you make changes to the file(s) in the node_modules directory then run a command like:

npx patch-package package-name

The package then performs the following steps:

1. Downloads the package-name package at the same version in the project's lock file to a temporary directory
2. Diffs the "clean" package against the version in node_modules and creates a patch file in a patches directory in the project root
3. Deletes the temporary directory

I was wondering whether there's any scope for doing that within this project? I'd be happy to give it a go and submit a PR but would like some feedback before starting :)

I see it working pretty similarly to the above method, with the addition of adding an entry to the extra.patches object in composer.json

[Liinkiing]

@andyexeter Hi! I've had the exam same feeling as you, and found this package that does exactly like the patch-package: https://github.com/symplify/vendor-patches, it actually uses underneath this package, so all is great! 🥳

[andyexeter]

@Liinkiing Thanks! That package looks awesome. I will keep this issue open for the time being, to see if the maintainer of this package would like this sort of functionality natively.

[cweagans]

I'd rather keep this plugin focused on applying patches, rather than generating them.