I'm just making some notes here for context:

• @mbishopim3 reported git fetch failing after the introduction of ssh-connect because it was trying to use default MySQL credentials
  • EXCEPTION: (AphrontQueryConnectionException) Attempt to connect to root@localhost failed with error #1045: Access denied for user 'root'@'localhost' (using password: NO).
• I guessed that this is because PHABRICATOR_ENV is not propagating correctly, and provided P1002 as a patch.
• This fixed the issue.

Normally, PHABRICATOR_ENV should propagate correctly on its own and the patch shouldn't be necessary. However, the implementation of setEnv() in ExecFuture uses $env + $_ENV if we aren't wiping the environment, and I believe $_ENV does not always populate correctly (for example, we use getenv() in PhabricatorEnv). This may be a function of variables_order omitting E.

I'm moving forward by promoting P1002 toward the upstream rather than dealing with $_ENV because this should be the only such variable which matters and being explicit should be safe and reasonable, but an alternate fix may be:

• Require $_ENV populate?
  • Test for it during configuration/setup?
  • Advise users to include E in variables_order if not present?

This is a more complicated fix to develop and test, but if we apply it at some point in the future we could revert the P1002 fix.