[migration] Improve update of in-memory schema during 3.18 CWAttribute.defaultval change
We weren't updating the schema properly so a bunch of structures still
had the old rdef with 'String' as object. That caused failures to add
new attributes later in the migration as their default value would be a
Binary object but the schema would expect a String.
Closes #3683640
from yams import schema2sql as y2sql
dbhelper = repo.system_source.dbhelper
rdefdef = schema['CWSource'].rdef('name')
attrtype = y2sql.type_from_constraints(dbhelper, rdefdef.object, rdefdef.constraints).split()[0]
cursor = session.cnxset['system']
sql('UPDATE entities SET asource = source WHERE asource is NULL')
dbhelper.change_col_type(cursor, 'entities', 'asource', attrtype, False)
dbhelper.change_col_type(cursor, 'entities', 'source', attrtype, False)
dbhelper.change_col_type(cursor, 'deleted_entities', 'source', attrtype, False)