1.4.0

1.4.0

Released: February 4, 2020

feature

• [feature] [batch] Added new parameters BatchOperations.add_column.insert_before,
  BatchOperations.add_column.insert_after which provide for
  establishing the specific position in which a new column should be placed.
  Also added Operations.batch_alter_table.partial_reordering
  which allows the complete set of columns to be reordered when the new table
  is created. Both operations apply only to when batch mode is recreating
  the whole table using recreate="always". Thanks to Marcin Szymanski
  for assistance with the implementation.

  References: #640

bug

• [bug] [autogenerate] Adjusted the unique constraint comparison logic in a similar manner as that
  of #421 did for indexes in order to take into account SQLAlchemy's
  own truncation of long constraint names when a naming convention is in use.
  Without this step, a name that is truncated by SQLAlchemy based on a unique
  constraint naming convention or hardcoded name will not compare properly.

  References: #647

• [bug] [autogenerate] A major rework of the "type comparison" logic is in place which changes the
  entire approach by which column datatypes are compared. Types are now
  compared based on the DDL string generated by the metadata type vs. the
  datatype reflected from the database. This means we compare types based on
  what would actually render and additionally if elements of the types change
  like string length, those changes are detected as well. False positives
  like those generated between SQLAlchemy Boolean and MySQL TINYINT should
  also be resolved. Thanks very much to Paul Becotte for lots of hard work
  and patience on this one.

  References: #605

usecase

• [usecase] [environment] Moved the use of the __file__ attribute at the base of the Alembic
  package into the one place that it is specifically needed, which is when
  the config attempts to locate the template directory. This helps to allow
  Alembic to be fully importable in environments that are using Python
  memory-only import schemes. Pull request courtesy layday.

  References: #648

misc

• [change] The internal inspection routines no longer use SQLAlchemy's
  Inspector.from_engine() method, which is expected to be deprecated in
  1.4. The inspect() function is now used.

1.3.3

1.3.3

Released: January 22, 2020

bug

• [bug] [postgresql] Fixed issue where COMMENT directives for PostgreSQL failed to correctly
  include an explicit schema name, as well as correct quoting rules for
  schema, table, and column names. Pull request courtesy Matthew Sills.

  References: #637

usecase

• [usecase] [operations] Added support for rendering of "computed" elements on Column
  objects, supported in SQLAlchemy via the new Computed element
  introduced in version 1.3.11. Pull request courtesy Federico Caselli.

  Note that there is currently no support for ALTER COLUMN to add, remove, or
  modify the "GENERATED ALWAYS AS" element from a column; at least for
  PostgreSQL, it does not seem to be supported by the database. Additionally,
  SQLAlchemy does not currently reliably reflect the "GENERATED ALWAYS AS"
  phrase from an existing column, so there is also no autogenerate support
  for addition or removal of the Computed element to or from an
  existing column, there is only support for adding new columns that include
  the Computed element. In the case that the Computed
  element is removed from the Column object in the table metadata,
  PostgreSQL and Oracle currently reflect the "GENERATED ALWAYS AS"
  expression as the "server default" which will produce an op that tries to
  drop the element as a default.

  References: #624

1.3.2

1.3.2

Released: December 16, 2019

bug

• [bug] [api] [autogenerate] Fixed regression introduced by #579 where server default rendering
  functions began to require a dialect implementation, however the
  render_python_code() convenience function did not include one, thus
  causing the function to fail when used in a server default context. The
  function now accepts a migration context argument and also creates one
  against the default dialect if one is not provided.

  References: #635

1.3.1

1.3.1

no release date

bug

• [bug] [mssql] Fixed bug in MSSQL dialect where the drop constraint execution steps used
  to remove server default or implicit foreign key constraint failed to take
  into account the schema name of the target table.

  References: #621

1.3.0

1.3.0

Released: October 31, 2019

feature

• [feature] [command] Added support for ALEMBIC_CONFIG environment variable,
  refers to the location of the alembic configuration script
  in lieu of using the -c command line option.

  References: #608

bug

• [bug] [autogenerate] Fixed bug in new Variant autogenerate where the order of the arguments to
  Variant were mistakenly reversed.

  References: #131

misc

• [change] [compatibility] Some internal modifications have been made to how the names of indexes and
  unique constraints work to make use of new functions added in SQLAlchemy
  1.4, so that SQLAlchemy has more flexibility over how naming conventions
  may be applied to these objects.

1.2.1

1.2.1

Released: September 24, 2019

bug

• [bug] [command] Reverted the name change of the "revisions" argument to
  command.stamp() to "revision" as apparently applications are
  calling upon this argument as a keyword name. Pull request courtesy
  Thomas Bechtold. Special translations are also added to the command
  line interface so that it is still known as "revisions" in the CLI.

  References: #601

• [bug] [tests] Removed the "test requirements" from "setup.py test", as this command now
  only emits a removal error in any case and these requirements are unused.

  References: #592

1.2.0

1.2.0

Released: September 20, 2019

• [command] [feature] Added new --purge flag to the alembic stamp command, which will
  unconditionally erase the version table before stamping anything. This is
  useful for development where non-existent version identifiers might be left
  within the table. Additionally, alembic.stamp now supports a list of
  revision identifiers, which are intended to allow setting up muliple heads
  at once. Overall handling of version identifiers within the
  alembic.stamp command has been improved with many new tests and
  use cases added.

  References: #473

• [autogenerate] [bug] Improved the Python rendering of a series of migration operations such that
  a single "pass" is rendered for a UpgradeOps or
  DowngradeOps based on if no lines of Python code actually
  rendered under the operation, rather than whether or not sub-directives
  exist. Removed extra "pass" lines that would generate from the
  ModifyTableOps directive so that these aren't duplicated under
  operation rewriting scenarios.

  References: #550

• [feature] [runtime] Added new feature MigrationContext.autocommit_block(), a special
  directive which will provide for a non-transactional block inside of a
  migration script. The feature requres that: the database driver
  (e.g. DBAPI) supports the AUTOCOMMIT isolation mode. The directive
  also necessarily needs to COMMIT the existing transaction in progress
  in order to enter autocommit mode.

  References: #123

• [change: py3k] Python 3.4 support is dropped, as the upstream tooling (pip, mysqlclient)
  etc are already dropping support for Python 3.4, which itself is no longer
  maintained.

• [autogenerate] [usecase] Added autogenerate support for Column objects that have
  dialect-specific **kwargs, support first added in SQLAlchemy 1.3.
  This includes SQLite "on conflict" as well as options used by some
  third party dialects.

  References: #518

• [autogenerate] [usecase] Added rendering for SQLAlchemy Variant datatypes, which render as the
  base type plus one or more .with_variant() method calls.

  References: #131

• [commands] [feature] Added "post write hooks" to revision generation. These allow custom logic
  to run after a revision Python script is generated, typically for the
  purpose of running code formatters such as "Black" or "autopep8", but may
  be used for any arbitrary post-render hook as well, including custom Python
  functions or scripts. The hooks are enabled by providing a
  [post_write_hooks] section in the alembic.ini file. A single hook
  is provided which runs an arbitrary Python executable on the newly
  generated revision script, which can be configured to run code formatters
  such as Black; full examples are included in the documentation.

  References: #307

• [commands] [usecase] Made the command interface revision lookup behavior more strict in that an
  Alembic revision number is only resolved based on a partial match rules if
  it has at least four characters, to prevent simple typographical issues
  from inadvertently running migrations.

  References: #534

• [environment] [feature] Added new flag --package to alembic init. For environments where
  the Alembic migration files and such are within the package tree and
  importable as modules, this flag can be specified which will add the
  additional __init__.py files in the version location and the
  environment location.

  References: #463

• [autogenerate] [bug] Fixed bug where rendering of comment text for table-level comments within
  Operations.create_table_comment() and
  Operations.drop_table_comment() was not properly quote-escaped
  within rendered Python code for autogenerate.

  References: #549

• [autogenerate] [bug] Modified the logic of the Rewriter object such that it keeps a
  memoization of which directives it has processed, so that it can ensure it
  processes a particular directive only once, and additionally fixed
  Rewriter so that it functions correctly for multiple-pass
  autogenerate schemes, such as the one illustrated in the "multidb"
  template. By tracking which directives have been processed, a
  multiple-pass scheme which calls upon the Rewriter multiple times
  for the same structure as elements are added can work without running
  duplicate operations on the same elements more than once.

  References: #505

1.1.0

1.1.0

Released: August 26, 2019

• [change] Alembic 1.1 bumps the minimum version of SQLAlchemy to 1.1. As was the
  case before, Python requirements remain at Python 2.7, or in the 3.x series
  Python 3.4.

• [change] [internals] The test suite for Alembic now makes use of SQLAlchemy's testing framework
  directly. Previously, Alembic had its own version of this framework that
  was mostly copied from that of SQLAlchemy to enable testing with older
  SQLAlchemy versions. The majority of this code is now removed so that both
  projects can leverage improvements from a common testing framework.

• [bug] [commands] Fixed bug where the double-percent logic applied to some dialects such as
  psycopg2 would be rendered in --sql mode, by allowing dialect options
  to be passed through to the dialect used to generate SQL and then providing
  paramstyle="named" so that percent signs need not be doubled. For
  users having this issue, existing env.py scripts need to add
  dialect_opts={"paramstyle": "named"} to their offline
  context.configure(). See the alembic/templates/generic/env.py template
  for an example.

  References: #562

• [bug] [py3k] Fixed use of the deprecated "imp" module, which is used to detect pep3147
  availability as well as to locate .pyc files, which started emitting
  deprecation warnings during the test suite. The warnings were not being
  emitted earlier during the test suite, the change is possibly due to
  changes in py.test itself but this is not clear. The check for pep3147 is
  set to True for any Python version 3.5 or greater now and importlib is used
  when available. Note that some dependencies such as distutils may still be
  emitting this warning. Tests are adjusted to accommodate for dependencies
  that emit the warning as well.

• [bug] [mysql] Fixed issue where emitting a change of column name for MySQL did not
  preserve the column comment, even if it were specified as existing_comment.

  References: #594

• [bug] [setup] Removed the "python setup.py test" feature in favor of a straight run of
  "tox". Per Pypa / pytest developers, "setup.py" commands are in general
  headed towards deprecation in favor of tox. The tox.ini script has been
  updated such that running "tox" with no arguments will perform a single run
  of the test suite against the default installed Python interpreter.

  References: #592

• [commands] [usecase] The "alembic init" command will now proceed if the target directory exists
  as long as it's still empty. Previously, it would not proceed if the
  directory existed. The new behavior is modeled from what git does, to
  accommodate for container or other deployments where an Alembic target
  directory may need to be already mounted instead of being created with
  alembic init. Pull request courtesy Aviskar KC.

  References: #571

1.0.11

1.0.11

Released: June 25, 2019

• [autogenerate] [batch] [bug] [sqlite] SQLite server default reflection will ensure parenthesis are surrounding a
  column default expression that is detected as being a non-constant
  expression, such as a datetime() default, to accommodate for the
  requirement that SQL expressions have to be parenthesized when being sent
  as DDL. Parenthesis are not added to constant expressions to allow for
  maximum cross-compatibility with other dialects and existing test suites
  (such as Alembic's), which necessarily entails scanning the expression to
  eliminate for constant numeric and string values. The logic is added to the
  two "reflection->DDL round trip" paths which are currently autogenerate and
  batch migration. Within autogenerate, the logic is on the rendering side,
  whereas in batch the logic is installed as a column reflection hook.

  References: #579

• [autogenerate] [bug] [sqlite] Improved SQLite server default comparison to accommodate for a text()
  construct that added parenthesis directly vs. a construct that relied
  upon the SQLAlchemy SQLite dialect to render the parenthesis, as well
  as improved support for various forms of constant expressions such as
  values that are quoted vs. non-quoted.

  References: #579

• [autogenerate] [bug] Fixed bug where the "literal_binds" flag was not being set when
  autogenerate would create a server default value, meaning server default
  comparisons would fail for functions that contained literal values.

• [bug] [mysql] Added support for MySQL "DROP CHECK", which is added as of MySQL 8.0.16,
  separate from MariaDB's "DROP CONSTRAINT" for CHECK constraints. The MySQL
  Alembic implementation now checks for "MariaDB" in server_version_info to
  decide which one to use.

  References: #554

• [bug] [mysql] [operations] Fixed issue where MySQL databases need to use CHANGE COLUMN when altering a
  server default of CURRENT_TIMESTAMP, NOW() and probably other functions
  that are only usable with DATETIME/TIMESTAMP columns. While MariaDB
  supports both CHANGE and ALTER COLUMN in this case, MySQL databases only
  support CHANGE. So the new logic is that if the server default change is
  against a DateTime-oriented column, the CHANGE format is used
  unconditionally, as in the vast majority of cases the server default is to
  be CURRENT_TIMESTAMP which may also be potentially bundled with an "ON
  UPDATE CURRENT_TIMESTAMP" directive, which SQLAlchemy does not currently
  support as a distinct field. The fix addiionally improves the server
  default comparison logic when the "ON UPDATE" clause is present and
  there are parenthesis to be adjusted for as is the case on some MariaDB
  versions.

  References: #564

• [bug] [environment] Warnings emitted by Alembic now include a default stack level of 2, and in
  some cases it's set to 3, in order to help warnings indicate more closely
  where they are originating from. Pull request courtesy Ash Berlin-Taylor.

• [bug] [py3k] Replaced the Python compatbility routines for getargspec() with a fully
  vendored version based on getfullargspec() from Python 3.3.
  Originally, Python was emitting deprecation warnings for this function in
  Python 3.8 alphas. While this change was reverted, it was observed that
  Python 3 implementations for getfullargspec() are an order of magnitude
  slower as of the 3.4 series where it was rewritten against Signature.
  While Python plans to improve upon this situation, SQLAlchemy projects for
  now are using a simple replacement to avoid any future issues.

  References: #563

1.0.10

1.0.10

Released: April 28, 2019

• [bug] [commands] Fixed bug introduced in release 0.9.0 where the helptext for commands
  inadvertently got expanded to include function docstrings from the
  command.py module. The logic has been adjusted to only refer to the first
  line(s) preceding the first line break within each docstring, as was the
  original intent.

  References: #552

• [bug] [mysql] [operations] Added an assertion in RevisionMap.get_revisions() and other methods
  which ensures revision numbers are passed as strings or collections of
  strings. Driver issues particularly on MySQL may inadvertently be passing
  bytes here which leads to failures later on.

  References: #551

• [autogenerate] [bug] [mysql] Fixed bug when using the
  EnvironmentContext.configure.compare_server_default flag set
  to True where a server default that is introduced in the table metadata
  on an Integer column, where there is no existing server default in the
  database, would raise a TypeError.

  References: #553