Spaces are not ignored in the "column" list of a uniqueConstraints

In a YAML configuration file

Behavior correct for this:

  uniqueConstraints:
    myConstraint:
      columns: column1,column2

However, if I add a space in the "columns" list:

  uniqueConstraints:
    myConstraint:
      columns: column1, column2

I end up with the following exception:

exception 'Doctrine\DBAL\Schema\SchemaException' with message 'There is no column with name ' column2' on table 'myTable'.

This can be very confusing, especially if (by any chance) you have a line return just on the space in the command line: you never see the space in the exception message.

It seems that YAML allows spaces in lists (http://en.wikipedia.org/wiki/YAML#Lists), but this line doesn't seem to be a YAML list. If it is parsed by Doctrine (split on ","), spaces should be ignored (or trimmed).