check does not work with ExecuteSQLOp present

[CaselIT]

Discussed in #1334

^{Originally posted by BayerSe October 23, 2023}
Hi,

we're using ExecuteSQLOp to add triggers to some columns.

With these added, alembic check nowadays raises a not implemented error, it seems as if because ExecuteSQLOp does not implement .to_diff_tuple().

op = ops.ExecuteSQLOp(sqltext='CREATE OR REPLACE TRIGGER ...')
op.to_diff_tuple()  # NotImplementedError

This used to work in version 1.6.5 and I think this error was introduced in 1.7.0 when .to_diff_tuple() was added to the base class MigrateOperation, see here.

Here's the stacktrace of alembic check:

INFO  [alembic.runtime.migration] Context impl OracleImpl.
INFO  [alembic.runtime.migration] Will assume non-transactional DDL.
INFO  [alembic.autogenerate.compare] Detected added table 'his_test'
Traceback (most recent call last):
  File "/home/user/PycharmProjects/project/.venv/bin/alembic", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/home/user/PycharmProjects/project/.venv/lib/python3.11/site-packages/alembic/config.py", line 630, in main
    CommandLine(prog=prog).main(argv=argv)
  File "/home/user/PycharmProjects/project/.venv/lib/python3.11/site-packages/alembic/config.py", line 624, in main
    self.run_cmd(cfg, options)
  File "/home/user/PycharmProjects/project/.venv/lib/python3.11/site-packages/alembic/config.py", line 601, in run_cmd
    fn(
  File "/home/user/PycharmProjects/project/.venv/lib/python3.11/site-packages/alembic/command.py", line 294, in check
    diffs = migration_script.upgrade_ops.as_diffs()
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/PycharmProjects/project/.venv/lib/python3.11/site-packages/alembic/operations/ops.py", line 2556, in as_diffs
    return list(OpContainer._ops_as_diffs(self))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/PycharmProjects/project/.venv/lib/python3.11/site-packages/alembic/operations/ops.py", line 2566, in _ops_as_diffs
    yield op.to_diff_tuple()
          ^^^^^^^^^^^^^^^^^^
  File "/home/user/PycharmProjects/project/.venv/lib/python3.11/site-packages/alembic/operations/ops.py", line 88, in to_diff_tuple
    raise NotImplementedError
NotImplementedError

I have no idea how this worked in 1.6.5 as already there, ExecuteSQLOp and some other ops did not have .to_diff_tuple(), but with .to_diff_tuple() in the base class check does not work as of today.

Thanks
Sebastian

[CaselIT]

Proposed solution from mike #1334 (reply in thread):

yes. see it does not normally make sense that ExecuteSQLOp would be in a diff stream unless as you are doing you have a hook adding it in. the "diff" then wants to show "what changed?" so here it would just be some code like "exec" and then a SQL statement. ill try to look at 1.6.5 to see what this would have done then.

[sqla-tester]

Sebastian Bayer (AE/MFD2-SO) has proposed a fix for this issue in the main branch:

Implement ExecuteSQLOp.to_diff_tuple https://gerrit.sqlalchemy.org/c/sqlalchemy/alembic/+/4914