Load plugins on composer install/update (v2)

[aschempp]

This re-adds #9

It works in my local test case, I'm not sure what the original problem with incomplete classes was.

[leofeyer]

This is impossible to review. Can you please make two separate PRs one for the PHP 7.1 upgrade and one for the actual changes from #9?

[aschempp]

I have merged the PHP 7.1 changes into master directly and removed them from this PR. Tests for the Plugin and Installer classes are currently missing, will add when we decide on this.

[leofeyer]

Does the code work for you? I remember having broken unit tests and getting incomplete PHP objects instead of bundle objects when I tried it the first time.

[aschempp]

I just tested this in a live installation and it works fine for me. I'm not sure this config in composer.json is good though?

{
    "extra": {
        "contao-manager": {
            "disabled-plugins": ["vendor/package"],
        }
    }
}

[leofeyer]

Regarding the discussion in https://github.com/contao/manager-bundle/pull/72#issuecomment-400568776, I would prefer to release these changes as version 3.0. Then we can also drop the $installedJson argument.

[aschempp]

I would prefer to release these changes as version 3.0

Not possible, because no extension could be installed anymore. The all require plugin v2

[leofeyer]

That's true.

[leofeyer]

Thank you @aschempp.