[FIXED] How to disable the removal of unused packages in composer?

Issue

I have many branches in git with different set of packages in composer.json

After each git checkout I need to do composer install and composer starts to download missing packages. In that moment, composer removes packages that are needed for other branch. And when I will checkout to other branch, I will need to download that packages again. When it comes to packages such as PHPUnit, Codeception or other frameworks, it takes a very long time.

Is it possible to disable the removal of unused packages in composer? (I have met this feature in bower or npm.)

Thank you.

Solution

Right now this is not supported, as install just performs the actions needed to comply to the project requirements. As technically in your case the requirements change, its behavior is correct. While the feature could be implemented in Composer it's not trivial, as it's 'unnatural' behavior that is quite low-level to hack.

However I think the real issue here is that your workflow is not correct. If different branches in Git have wildly different dependencies it is first of all doubtful that they should really be branches, and not entirely different repositories as they're really different projects then.

If that is not the case the easiest solution is just to clone the repository multiple times, and keep the different clones at their respective branches. That solves all your problems immediately and lets Composer do its work like it was intended. This is also a very common workflow in bigger projects, as in-place branch switching is really only practical for short-lived branches like PR's and feature branches.

Answered By - Niels Keurentjes