Trying to get repr() or str() on a queryset that has been .select_for_update() causes oracle backend to throw ORA00907

[kimvais@…]

Doing anything that would get a string representation of any QuerySet that has been selected for update (.select_of_update()) on oracle backend causes the following stacktrace

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.6/site-packages/django/db/models/query.py", line 77, in __repr__
    data = list(self[:REPR_OUTPUT_SIZE + 1])
  File "/usr/lib/python2.6/site-packages/django/db/models/query.py", line 92, in __len__
    self._result_cache.extend(self._iter)
  File "/usr/lib/python2.6/site-packages/django/db/models/query.py", line 301, in iterator
    for row in compiler.results_iter():
  File "/usr/lib/python2.6/site-packages/django/db/models/sql/compiler.py", line 775, in results_iter
    for rows in self.execute_sql(MULTI):
  File "/usr/lib/python2.6/site-packages/django/db/models/sql/compiler.py", line 840, in execute_sql
    cursor.execute(sql, params)
  File "/usr/lib/python2.6/site-packages/django/db/backends/oracle/base.py", line 717, in execute
    six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
  File "/usr/lib/python2.6/site-packages/django/db/backends/oracle/base.py", line 710, in execute
    return self.cursor.execute(query, self._param_generator(params))
django.db.utils.DatabaseError: ORA-00907: missing right parenthesis

[Tim Graham]

Reproduced with the attached regression test.

[Shai Berger]

As can be seen in the stack trace, this is because the query is sliced for presentation -- which means this is really a duplicate of the more focused #23147.

The test case should be added when the problem is solved, though.