ensure that only one migration command is running on one db

[cebe]

to avoid broken db states, ensure that only one db migration command is running.
this is relevant for environments such as testing servers that run migrations automatically.

[samdark]

You mean implementing some kind of exclusive lock?

[samdark]

I think that can be a good enhancement for Yii core migrations.

[cebe]

okay, will think about a solution that fits core migrations.