When using --sql the current revision seems unknown

[sqlalchemy-bot]

Migrated issue, originally created by xealot (@xealot)

Running this command:

$ alembic upgrade head

Alembic correctly starts from the revision which is set in the alembic_version table as expected. However after adding a --sql flag, Alembic no longer attempts to read the version from the DB and so the output is always from the beginning of all migrations.

$ alembic upgrade head --sql

Alternatively when I attempt to use --autogenerate with --sql in some cases I get the error "Database is not up to date". I assume this is because of the same or similar reason.

Am I missing something? Something that makes --sql behave the same as when not using --sql.

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

• The alembic revision command accepts the --sql option to
  suit some very obscure use case where the revision_environment
  flag is set up, so that env.py is run when alembic revision
  is run even though autogenerate isn't specified. As this flag is
  otherwise confusing, error messages are now raised if
  alembic revision is invoked with both --sql and
  --autogenerate or with --sql without
  revision_environment being set.
  fixes #248

→ 15376ba

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• changed status to closed

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

--autogenerate is an instruction that specifically requires that a database connection is present, so in the absense of very unique customizations to one's env.py, there's no reason you'd want to use --autogenerate with --sql and in fact there's never any reason to use --sql with alembic revision at all; this flag is allowed apparently as a means to help very specific env.py setups.

For upgrading/downgrading in --sql mode while being able to control the starting revision, please see
http://alembic.readthedocs.org/en/rel_0_6/tutorial.html#getting-the-start-version.

[sqlalchemy-bot]

xealot (@xealot) wrote:

Gah, sorry for the trouble. I was all over this section of the documentation and I thought I this pattern. I must have done something stupid because it does indeed work. Thanks again.

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

the --sql flag accepted by alembic revision is completely screwy and I think i need that a long time ago for something, so thanks for bringing it up that its confusing!

[sqlalchemy-bot]

xealot (@xealot) wrote:

I didn't actually need the command but I too thought it didn't make sense so I thought I would see what happened. It felt like the same error to me so I mentioned it. My use case is definitely with the update/downgrade command.