Investigate adding rule to detect FormField types from dataFieldByValue

[silbinarywolf]

Currently get errors like:

Call to an undefined method FormField::getConfig().

When using $fields->dataFieldByValue('Name'); wherein 'Name' is a GridField.
Would like to see if I can add some complex checks so that the correct type can be determined.

EDIT: I might look into executing scaffoldFormFields directly on a singleton() so that the exact form fields and structure are retained.

[nglasl]

@silbinarywolf can you please confirm if this is still an issue? I noticed heaps of commit references above, but they seem unrelated?

[nglasl]

Confirmed on #1 and #18.

[sminnee]

Incidentally this discussion relates: silverstripe/silverstripe-framework#9659

In the end it seems like doing this was preferred to adding more code to core for this:

$field = $fieldList->fieldByName('MyTable');
assert($field instanceof GridField);
$field->getConfig()->bla...