Partial custom fields design document

[Joel Peshkin]

Gervase Markham wrote:

>
> If we are making custom fields product-specific instead of global 
> (which I believe is the plan), then we shouldn't add them to the bugs 
> table.
>
The problem with that particular item is that it is a terrible plan.  
Having custom fields come and go from the UI on a per-product basis is 
great.  Having them come and go from the DB on a per-product basis is a 
recipe for dataloss.  Once a bug has a custom field, it should be stuck 
with that field forever, even if it is moved to a product where that 
field is not supported and then back again.