Name of unit of measurements should be unique per category

[Marco Dieckhoff]

You can add two Unit of Measurements named "kg" (with the same, or even more severe: with different ratios), in the same category.

To avoid confusion and inconsistent data, the name of the unit should be unique (per category).

This is, among other usages, quite neccessary for external unit conversion e.g. programs contacting OpenERP via xmlrpc.

[Amit Parik (amit-parik)]

Hello,

This bug is generated only in stable 6.0 because in trunk version constraint putted in UOM.

Thanks.

[Amit Dodiya (OpenERP) (ado-openerp)]

Hello Marco,

Its fixed in https://code.launchpad.net/~openerp-dev/openobject-addons/6.0-bug-734686-ado.

It will be merged soon with stable addons branch.

Thanks.

[Olivier Dony (Odoo) (odo-openerp)]

Marco,

Any particular reason you think UoM names should be unique only *per category*? Given that UoMs are like currencies, I would think as their names as being reference "keys", so they should be globally unique, not just within a category.
This would make it even better/easier for external unit conversion.

Or do you have an example where you think using the same UoM name in 2 categories is valid?

PS: I changed status to Confirmed because it does not look like the proposed patch/branch correctly addresses this issue.

[Olivier Dony (Odoo) (odo-openerp)]

BTW, the related fix from trunk came from bug 731035, which I'm not sure was correctly addressed, we may need to reconsider it.

[Marco Dieckhoff (dieck)]

I'm trying hard to remember why I added that "per category".

Even trying to construct a hypothetical case, I can't find any reason.
The only thing that would matter would be equal named units with different meanings, like minutes are time and astronomical angle. But that's way of all use cases I could expect.

I think it was just a mere minimal requirement and can be superseeded by a stronger constraint like "for all".

[Steffi Frank (Bremskerl, DE) (steffi-frank)]

a reason to do it by category would be: stock unit = kg, purchase unit = pce. Therefor you would define 'pce' in category 'weight' as well....

[Marco Dieckhoff (dieck)]

That's a very (very) specialised case, where ALL products you have are of the same weight, to not mess it up.

Here, we had such a special case, something bought as m³ (cubic metres, had to be called on the purchase order like this) and sold as kg.

I think the common way would have been to do a "unit conversion" by manufacturing, but that was too much overhead.

So we added a unit for m³ to weight. But even here, we wanted to avoid any misunderstandings, esp. with future products that may be added, and called it "m³ (48kg)", thus identifying it uniquely.

[Olivier Dony (Odoo) (odo-openerp)]

Steffi and Marco, thanks for the additional details. I guess this
confirms the general rule, so let's go for that.