[10.0][MIG][base_import_match] Migration and update

Includes:

- Normal migration steps.
- Usage of brand new `_inherit = "base"` in Odoo 10, which implies
  removing a lot of monkey-patching code.
- Log a warning when multiple matches are found.

base_import_match/models/base.py

@@ -0,0 +1,54 @@
+# -*- coding: utf-8 -*-
+# Copyright 2017 Jairo Llopis <jairo.llopis@tecnativa.com>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+from odoo import api, models
+
+
+class Base(models.AbstractModel):
+    _inherit = "base"
+
+    @api.model
+    def load(self, fields, data):
+        """Try to identify rows by other pseudo-unique keys.
+
+        It searches for rows that have no XMLID specified, and gives them
+        one if any :attr:`~.field_ids` combination is found. With a valid
+        XMLID in place, Odoo will understand that it must *update* the
+        record instead of *creating* a new one.
+        """
+        # We only need to patch this call if there are usable rules for it
+        if self.env["base_import.match"]._usable_rules(self._name, fields):
+            newdata = list()
+            # Data conversion to ORM format
+            import_fields = map(models.fix_import_export_id_paths, fields)
+            converted_data = self._convert_records(
+                self._extract_records(import_fields, data))
+            # Mock Odoo to believe the user is importing the ID field
+            if "id" not in fields:
+                fields.append("id")
+                import_fields.append(["id"])
+            # Needed to match with converted data field names
+            clean_fields = [f[0] for f in import_fields]
+            for dbid, xmlid, record, info in converted_data:
+                row = dict(zip(clean_fields, data[info["record"]]))
+                match = self
+                if xmlid:
+                    # Skip rows with ID, they do not need all this
+                    row["id"] = xmlid
+                    continue
+                elif dbid:
+                    # Find the xmlid for this dbid
+                    match = self.browse(dbid)
+                else:
+                    # Store records that match a combination
+                    match = self.env["base_import.match"]._match_find(
+                        self, record, row)
+                # Give a valid XMLID to this row if a match was found
+                row["id"] = (match._BaseModel__export_xml_id()
+                             if match else row.get("id", u""))
+                # Store the modified row, in the same order as fields
+                newdata.append(tuple(row[f] for f in clean_fields))
+            # We will import the patched data to get updates on matches
+            data = newdata
+        # Normal method handles the rest of the job
+        return super(Base, self).load(fields, data)