DataList->column mutates underlying DataQuery

[MasonD]

Affected Version

Silverstripe 4.5

Description

DataList->column calls distinct(false) on its DataQuery without cloning it first, causing errors if the DataList is used for anything else afterwards.

Steps to Reproduce

Have a member in multiple groups. Run the following code.

$members = Member::get()->applyRelation('Groups.ID');
$members->column('ID'); // This mutates the DataQuery of $members and removes distinct.
foreach ($members as $member) {
    echo $member->Name . "\n"; // members with multiple groups are represented multiple times
}

[sminnee]

Nice find - do you want to do a pull request?

[MasonD]

Sure thing. Which branch should I target?

[sminnee]

Since it's a bug I think 4.6 is fine