add a fixed version of core's InstallCommand

[joachim-n]

Core's InstallCommand makes assumptions about Drupal's location. There's no workaround for this -- they're hardcoded.

One fix would be for this add-on to provide its own fixed version of the InstallCommand class -- there is one in the MR for https://www.drupal.org/node/1792310.

Though there's also an issue to make Drush commands work with this - #29 - in which case fixing drupal install might not be necessary.

[justafish]

This addon is geared towards developing core with the git checkout so it does make an assumption about Drupal's location. Please feel free to re-open if this changes in core.

[joachim-n]

It is, but it would be good if it also supported developing core when installed using a Composer path repository. This is the standard way of developing a Composer package in the wider context of a project.