dupe entries in alembic_versions can break revision logic

[sqlalchemy-bot]

Migrated issue, originally created by Michael Bayer (@zzzeek)

e.g.

#!


sqlite> select * from alembic_version;
32f69b44319
32f69b44319

this should raise an error on the stamp, but versioning fails:

#!


Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/runpy.py", line 170, in _run_module_as_main
    "__main__", mod_spec)
  File "/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/Users/classic/tmp/alembic_0_7_7/alembic/config.py", line 442, in <module>
    main()
  File "/Users/classic/tmp/alembic_0_7_7/alembic/config.py", line 439, in main
    CommandLine(prog=prog).main(argv=argv)
  File "/Users/classic/tmp/alembic_0_7_7/alembic/config.py", line 433, in main
    self.run_cmd(cfg, options)
  File "/Users/classic/tmp/alembic_0_7_7/alembic/config.py", line 416, in run_cmd
    **dict((k, getattr(options, k)) for k in kwarg)
  File "/Users/classic/tmp/alembic_0_7_7/alembic/command.py", line 193, in downgrade
    script.run_env()
  File "/Users/classic/tmp/alembic_0_7_7/alembic/script.py", line 390, in run_env
    util.load_python_file(self.dir, 'env.py')
  File "/Users/classic/tmp/alembic_0_7_7/alembic/util.py", line 244, in load_python_file
    module = load_module_py(module_id, path)
  File "/Users/classic/tmp/alembic_0_7_7/alembic/compat.py", line 68, in load_module_py
    module_id, path).load_module(module_id)
  File "<frozen importlib._bootstrap>", line 539, in _check_name_wrapper
  File "<frozen importlib._bootstrap>", line 1614, in load_module
  File "<frozen importlib._bootstrap>", line 596, in _load_module_shim
  File "<frozen importlib._bootstrap>", line 1220, in load
  File "<frozen importlib._bootstrap>", line 1200, in _load_unlocked
  File "<frozen importlib._bootstrap>", line 1129, in _exec
  File "<frozen importlib._bootstrap>", line 1471, in exec_module
  File "<frozen importlib._bootstrap>", line 321, in _call_with_frames_removed
  File "foo/env.py", line 70, in <module>
    run_migrations_online()
  File "foo/env.py", line 65, in run_migrations_online
    context.run_migrations()
  File "<string>", line 7, in run_migrations
  File "/Users/classic/tmp/alembic_0_7_7/alembic/environment.py", line 738, in run_migrations
    self.get_context().run_migrations(**kw)
  File "/Users/classic/tmp/alembic_0_7_7/alembic/migration.py", line 302, in run_migrations
    for step in self._migrations_fn(heads, self):
  File "/Users/classic/tmp/alembic_0_7_7/alembic/command.py", line 182, in downgrade
    return script._downgrade_revs(revision, rev)
  File "/Users/classic/tmp/alembic_0_7_7/alembic/script.py", line 315, in _downgrade_revs
    current_rev, destination)
  File "/Users/classic/tmp/alembic_0_7_7/alembic/revision.py", line 512, in iterate_revisions
    inclusive, assert_relative_length
  File "/Users/classic/tmp/alembic_0_7_7/alembic/revision.py", line 450, in _relative_iterate
    inclusive=inclusive, implicit_base=implicit_base))
  File "/Users/classic/tmp/alembic_0_7_7/alembic/revision.py", line 672, in _iterate_revisions
    total_space.remove(rev.revision)
KeyError: '32f69b44319'

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

if we have an 0.7.8, then backport. otherwise keep it in 0.8.

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

• Fixed bug where in the erroneous case that alembic_version contains
  duplicate revisions, some commands would fail to process the
  version history correctly and end up with a KeyError. The fix
  allows the versioning logic to proceed, however a clear error is
  emitted later when attempting to update the alembic_version table.
  fixes dupe entries in alembic_versions can break revision logic #314

→ e155fa6

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• changed status to closed