Fix numeric natural keys resolving to the wrong asset on import

shopdb/core/services/csvimport.py

@@ -427,12 +427,41 @@ class Resolver:
     def resolve(self, tablename, idcolumn, value):
         if value is None:
             return None
-        # A number is taken at face value: exports round-trip, and some sites do
-        # know their ids.
-        if isinstance(value, int) or (isinstance(value, str) and value.strip().isdigit()):
+        # An int is an id. It cannot be anything else.
+        if isinstance(value, int):
             return int(value)
 
         label = _label_column(tablename)
+
+        # An ALL-DIGIT STRING IS AMBIGUOUS, and used to be taken at face value
+        # as an id. That is wrong wherever a site's natural keys are numeric,
+        # and this one numbers operations 0NNN: assetnumber `0600` was read as
+        # id 600, which is a different asset - a printer, in the case that
+        # found this - or none at all, which surfaced as a foreign-key error
+        # partway through an Azure device import.
+        #
+        # The label wins when one matches. Somebody writing `0600` in a column
+        # keyed on assetnumber means the asset called 0600, and silently
+        # binding a row to an unrelated record is far worse than the error.
+        # Fall through to the id reading only when no label matches, which
+        # keeps round-tripped exports and sites that do know their ids working.
+        if isinstance(value, str) and value.strip().isdigit():
+            if label:
+                key = (tablename, value.strip().lower())
+                if key in self._cache:
+                    return self._cache[key]
+                table = db.metadata.tables[tablename]
+                row = db.session.execute(
+                    table.select().where(
+                        db.func.lower(db.func.trim(table.c[label]))
+                        == value.strip().lower())
+                ).first()
+                if row is not None:
+                    found = getattr(row, idcolumn)
+                    self._cache[key] = found
+                    return found
+            return int(value)
+
         if not label:
             raise ValueError(
                 "cannot look up %s by name - give the numeric %s instead" % (tablename, idcolumn))