Preserve comments in DrupalVM config when adding multisites.

[danepowell]

Workaround for lack of comment support in Symfony YAML parser: symfony/symfony#22516

This isn't tied to a particular ticket, just something that bothered me when refactoring the multisite command previously.

To test, run blt multisite on a BLT project using DrupalVM, and opt to let it update your DrupalVM configuration. You should see that most (not all) of the comments in box/config.yml are preserved.

[alexxed]

Any way this can have a meaningful test? You rely on an external package to edit a very specific, but important user yaml file. If that package is upgraded and breaks it we won't know without tests.

[danepowell]

We can't test DrupalVM in TravisCI or Pipelines. The best we could do is to write a unit test with a mock DrupalVM config file to make sure consolidation/comments rewrites it as expected. Of course, at that point we've basically just duplicated consolidation/comments's own tests: https://github.com/consolidation/comments/blob/master/tests/TestYamlComments.php

Seems like that would have negligible value.

[alexxed]

Right, I was thinking of a test that edits a regular drupalvm yml file with comments and checks that it does not break it, e.g. only what was changed is changed.

[adrianthedev]

Looks good!