One of our customers is selling goods to IRAN. He has the IRANI fiscal number but this is not available as Tryton tax identifier (neither it is available on python-stdnum).
Altought this can be entered as other type on the party form, this has the drawback that the tax identifier is not automatically selected when issuing the invoice so the user needs to manually check that the field is filled before posting the invoice, causing some problems as they sometimes forget about it.
I’m wondering if it will be a good idea to have a “Other tax identifier” selection option in the types of identifiers which is not validated by python-stdnum but is considered a tax identifier.
I do not see the point. You can add any extra type on identifier (as long as it does not contain _ it will not be tested with python-stdnum). And you can add this identifier to the tax identifier types list.
Well the tax identifier is not very important when doing international trading because there is no taxes to deduce.
Also user can fill the number in the description for example and if they want to be rid of this they will just add it to python-stdnum.
Globally I dislike the idea of adding a carryall tax identifier because it will be misused (for example to skip validation).
Maybe if we make filling such non-validated tax identifier hard enough it will not be misused. For example we could raise a warning when created or modified. Also we could check that it is not a valid VATIN and so we reject it.