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``aspectlib`` is an aspect-oriented programming, monkey-patch and decorators library. It is useful when changing

Project Description

aspectlib is an aspect-oriented programming, monkey-patch and decorators library. It is useful when changing behavior in existing code is desired. It includes tools for debugging and testing: simple mock/record and a complete capture/replay framework.

  • Free software: BSD license


pip install aspectlib


Docs are hosted at python-aspectlib docs.

Implementation status

Weaving functions, methods, instances and classes is completed.


  • “Concerns” (see docs/todo.rst)

If aspectlib.weave doesn’t work for your scenario please report a bug!


Runtime:Python 2.6, 2.7, 3.3, 3.4 or PyPy

Python 3.2, 3.1 and 3.0 are NOT supported (some objects are too crippled).

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1.4.2 (2016-05-10)

  • Fix forgotten debug prints.

1.4.1 (2016-05-06)

  • Fixed weaving of objects that don’t live on root-level modules.

1.4.0 (2016-04-09)

  • Corrected weaving of methods, the weaved function should be unbound.
  • Rolling back only applies undos once.
  • Added a convenience weave fixture for pytest.

1.3.3 (2015-10-02)

  • Fixed typo in ABSOLUTELLY_ALL_METHODS name (now ABSOLUTELY_ALL_METHODS). Old name is still there for backwards compatibility.

1.3.2 (2015-09-22)

  • Fixed another tricky bug in the generator advising wrappers - result was not returned if only Proceed was yielded.

1.3.1 (2015-09-12)

  • Corrected result handling when using Aspects on generators.

1.3.0 (2015-06-06)

  • Added messages property to aspectlib.test.LogCapture. Change call to have level name instead of number.
  • Fixed a bogus warning from aspectlib.patch_module` when patching methods on old style classes.

1.2.2 (2014-11-25)

  • Added support for weakrefs in the __logged__ wrapper from aspectlib.debug.log decorator.

1.2.1 (2014-10-15)

  • Don’t raise exceptions from Replay.__exit__ if there would be an error (makes original cause hard to debug).

1.2.0 (2014-06-24)

  • Fixed weaving methods that were defined in some baseclass (and not on the target class).
  • Fixed wrong qualname beeing used in the Story/Replay recording. Now used the alias given to the weaver instead of whatever is the realname on the current platform.

1.1.1 (2014-06-14)

  • Use ASPECTLIB_DEBUG for every logger in aspectlib.

1.1.0 (2014-06-13)

  • Added a bind option to aspectlib.Aspect so you can access the cutpoint from the advisor.
  • Replaced automatic importing in aspectlib.test.Replay with extraction of context variables (locals and globals from the calling aspectlib.test.Story). Works better than the previous inference of module from AST of the result.
  • All the methods on the replay are now properties: aspectlib.test.Story.diff, aspectlib.test.Story.unexpected and aspectlib.test.Story.missing.
  • Added aspectlib.test.Story.actual and aspectlib.test.Story.expected.
  • Added an ASPECTLIB_DEBUG environment variable option to switch on debug logging in aspectlib’s internals.

1.0.0 (2014-05-03)

  • Reworked the internals aspectlib.test.Story to keep call ordering, to allow dependencies and improved the serialization (used in the diffs and the missing/unexpected lists).

0.9.0 (2014-04-16)

  • Changed aspectlib.test.record:

    • Renamed history option to calls.
    • Renamed call option to iscalled.
    • Added callback option.
    • Added extended option.
  • Changed aspectlib.weave:

    • Allow weaving everything in a module.
    • Allow weaving instances of new-style classes.
  • Added aspectlib.test.Story class for capture-replay and stub/mock testing.

0.8.1 (2014-04-01)

  • Use simpler import for the py3support.

0.8.0 (2014-03-31)

  • Change aspectlib.debug.log to use aspectlib.Aspect and work as expected with coroutines or generators.
  • Fixed aspectlib.debug.log to work on Python 3.4.
  • Remove the undocumented aspectlib.Yield advice. It was only usable when decorating generators.

0.7.0 (2014-03-28)

  • Add support for decorating generators and coroutines in aspectlib.Aspect.
  • Made aspectlib raise better exceptions.

0.6.1 (2014-03-22)

  • Fix checks inside aspectlib.debug.log that would inadvertently call __bool__/__nonzero.

0.6.0 (2014-03-17)

  • Don’t include __getattribute__ in ALL_METHODS - it’s too dangerous dangerous dangerous dangerous dangerous dangerous … ;)
  • Do a more reliable check for old-style classes in debug.log
  • When weaving a class don’t weave attributes that are callable but are not actually routines (functions, methods etc)

0.5.0 (2014-03-16)

  • Changed aspectlib.debug.log:

    • Renamed arguments to call_args.
    • Renamed arguments_repr to call_args_repr.
    • Added call option.
    • Fixed issue with logging from old-style methods (object name was a generic “instance”).
  • Fixed issues with weaving some types of builtin methods.

  • Allow to apply multiple aspects at the same time.

  • Validate string targets before weaving. aspectlib.weave('mod.invalid name', aspect) now gives a clear error (invalid name is not a valid identifier)

  • Various documentation improvements and examples.

0.4.1 (2014-03-08)

  • Remove junk from 0.4.0’s source distribution.

0.4.0 (2014-03-08)

  • Changed aspectlib.weave:

    • Replaced only_methods, skip_methods, skip_magicmethods options with methods.
    • Renamed on_init option to lazy.
    • Added aliases option.
    • Replaced skip_subclasses option with subclasses.
  • Fixed weaving methods from a string target.

0.3.1 (2014-03-05)

  • ???

0.3.0 (2014-03-05)

  • First public release.

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