I want to get data from foreign keys (what I believe in the codebase is called "subfields" [1]) of the account.move.line model.

I expected the field name format used in the "/web/export/csv" endpoint also worked for the XML-RPC operations, but it seems not to be the case.

This is an excerpt of my code:

# OpenERP 6.1.1
args = [('account_id', 'ilike', account_id), ]
line_ids = sock.execute(dbname, uid, pwd, 'account.move.line', 'search', args)
fields = ['id', 'move_id/name', 'move_id/ref', 'move_id/state', 'period_id', 'date', 'journal_id/name', 'account_id/code', 'account_id/name', 'ref', 'name', 'partner_id/name', 'debit', 'credit', 'amount_currency', 'currency_id/name', 'date_maturity', 'reconcile_id/name']
lines = sock.execute(dbname, uid, pwd, model, 'read', ids, fields)
pprint(lines[0])
# The resulting records do not contain these fields: "X/Y" (eg. move_id/state)
#  {'amount_currency': 0.0,
#  'credit': 0.0,#  'date': '2016-04-29',
#  'date_maturity': False,#  'debit': 0.0,
#  'id': 186462,#  'name': '[35975.00882] 031003-03 Metallic Blank Plate for Panels',
#  'ref': 'DIM-MovSal-2016-04376'}

[1] https://github.com/odoo/odoo/blob/fc2e80cb4bcc450762c7ac5cb82a3e2d88062b38/addons/web/controllers/main.py#L1222