base_business_document_import: selecting partner in a multicompany environment

[astirpe]

Tested with 11.0.

Here is the scenario:

• In a multicompany environment, user A is allowed to access multiple companies, eg. Company1 and Company2.
• For Company1, a vendor (partner) with vat number = XYX is present.
• In Company2 there is also a vendor with same vat number = XYX; so that vendor is known in both Company1 and Company2.
• The module base_business_document_import is capable to select the partner based on the result of method def _match_partner(). In our scenario, the match is based on the vat number: see lines.

User A logs in with Company1 and tries to import a document (eg. an invoice).

I would expect that the retrieved vendor (partner) is the one with vat = XYX belonging to Company1.
But it could happen that the def _match_partner() retrieves the wrong partner: the one of Company2.

Adding ('company_id', '=', self.env.user.company_id.id) in the domain of these lines seems fixing the problem.
However there could be other cases where a patch is needed in order to make the module multicompany compliant.
I don't have time to investigate further and I will not have time to propose a PR during the next weeks, so I open this issue as a reminder to open a PR. In the meanwhile any help will be very appreciated!