Cannot run migration when using timestamp version numbers

[Andrew]

The changeset method in migrate/versioning/repository.py (around line 200), does not work for timestamped version numbers. The list comprehension which determines the set of versions between :start: and :end: assumes that the versions are 1 apart from each other. This is obviously wrong (most of the time) when using timestamped version numbers, resulting in the following traceback:

Traceback (most recent call last):
  File "/Users/andrew/work/incubator/hilo-backend/venv/bin/migrate", line 11, in <module>
    sys.exit(main())
  File "/Users/andrew/work/incubator/hilo-backend/venv/lib/python3.4/site-packages/migrate/versioning/shell.py", line 209, in main
    ret = command_func(**kwargs)
  File "/Users/andrew/work/incubator/hilo-backend/venv/lib/python3.4/site-packages/migrate/versioning/api.py", line 186, in upgrade
    return _migrate(url, repository, version, upgrade=True, err=err, **opts)
  File "<decorator-gen-15>", line 2, in _migrate
  File "/Users/andrew/work/incubator/hilo-backend/venv/lib/python3.4/site-packages/migrate/versioning/util/__init__.py", line 160, in with_engine
    return f(*a, **kw)
  File "/Users/andrew/work/incubator/hilo-backend/venv/lib/python3.4/site-packages/migrate/versioning/api.py", line 345, in _migrate
    changeset = schema.changeset(version)
  File "/Users/andrew/work/incubator/hilo-backend/venv/lib/python3.4/site-packages/migrate/versioning/schema.py", line 82, in changeset
    changeset = self.repository.changeset(database, start_ver, version)
  File "/Users/andrew/work/incubator/hilo-backend/venv/lib/python3.4/site-packages/migrate/versioning/repository.py", line 225, in changeset
    changes = [self.version(v).script(database, op) for v in versions]
  File "/Users/andrew/work/incubator/hilo-backend/venv/lib/python3.4/site-packages/migrate/versioning/repository.py", line 225, in <listcomp>
    changes = [self.version(v).script(database, op) for v in versions]
  File "/Users/andrew/work/incubator/hilo-backend/venv/lib/python3.4/site-packages/migrate/versioning/repository.py", line 189, in version
    return self.versions.version(*p, **k)
  File "/Users/andrew/work/incubator/hilo-backend/venv/lib/python3.4/site-packages/migrate/versioning/version.py", line 163, in version
    return self.versions[VerNum(vernum)]
KeyError: <VerNum(1)>

[Andrew (mason-y)]

 Closes-Bug: 1512561

This is a quick work-around. The code for sequentially versioned schemas
is left unchanged, but this approach would probably work for those
version numbers as well.

All tests are passing on python 2.x. On python 3.x, there are 4
failures, but none appear related to this change.

[Andrew (mason-y)]

Somehow was able to delete my previous patch, but not change it... oh well.

Anyway, I made a mistake with regards to strictness of inequalities for lower/upper bounds for upgrade/downgrade.
Here is the first part of the patch.

[Andrew (mason-y)]

And here is the second part.

[Andrew (mason-y)]

fixes the lower bound on downgrades, with the added bonus of simplifying some code

[Swati (swatisinghi)]

I still see the issue, is the patch not applied to the main branch. I used pip install sqlalchemy-migrate to install the module. Please help.