Injector Change Log


  • Fixed handling of Union combined with Annotated, thanks to Tobias Nilsson
  • Fixed AssitedBuilder/child Injector interaction, thanks to Erik Cederberg
  • Made get_bindings() and injections work even if a injectee’s return type annotation is a forward reference that can’t be resolved

Backwards incompatible:

  • Dropped Python 3.6 support


  • Added the license to the source distribution, thanks to Joshua Adelman
  • Added Python 3.9 and 3.10 support, this includes fixing Python 3.10 compatibility, thanks to Torge Matthies
  • Improved the documentation, thanks to Takahiro Kojima
  • Improved the source distribution so that it can be used to build and install wheels, thanks to Janusz Skonieczny
  • Added requirements files for easier development, thanks to Greg Eremeev

Backwards incompatible:

  • Removed Python 3.5 support


  • Fixed a bug where only one of multiple NoInject annotations was interpreted


  • Fixed Python 3.5.3 compatibility


  • Added remaining type hints to the codebase so that the client code can have better static typing safety
  • Fixed UnsatisfiedRequirement string representation (this time for real)
  • Added forward return type reference support to provider methods


  • Fixed UnsatisfiedRequirement instantiation (trying to get its string representation would fail)
  • Fixed injecting a subclass of a generic type on Python versions older than 3.7.0
  • Fixed regression that caused BoundKey injection failure


  • Added new public get_bindings function to see what parameters will be injected into a function
  • Added new generic types using a draft implementation of PEP 593: Inject and NoInject. Those serve as additional ways to declare (non)injectable parameters while inject won’t go away any time soon noninjectable may be removed once NoInject is cofirmed to work.

Backwards incompatible:

  • Removed previously deprecated Key, BindingKey, SequenceKey and MappingKey pseudo-types


  • Added support for using typing.Dict and typing.List in multibindings. See multibind.
  • Added multibinding-specific provider variant: multiprovider
  • Deprecated using provider for multibindings
  • Fixed failure to provide a default value to a NewType-aliased type with auto_bind enabled
  • Deprecated Key, SequenceKey and MappingKey – use real types or type aliases instead
  • Deprecated using single-item lists and dictionaries for multibindings - use real types or type aliases instead

Technically backwards incompatible:

  • typing.List and typing.Dict specializations are now explicitly disallowed as bind interfaces and types returned by provider-decorated methods


  • (Re)added support for decorating classes themselves with @inject. This is the same as decorating their constructors. Among other things this gives us dataclasses integration.


  • Reuploaded to fix incorrectly formatted project description


  • Added support for overriding injectable parameters with positional arguments (previously only possible with keyword arguments)
  • Fixed crashes caused by typed self in method signatures
  • Improved typing coverage

Backwards incompatible:

  • Dropped Python 3.4 support
  • Removed previously deprecated constructs: with_injector, Injector.install_into, Binder.bind_scope
  • Dependencies are no longer injected into Module.configure and raw module functions (previously deprecated)

- Removed unofficial support for injecting into parent class constructors


  • Added type information for Injector.create_object() (patch #101 thanks to David Pärsson)
  • Made the code easier to understand (patch #105 thanks to Christian Clauss)
  • Opted the package into distributing type information and checking it (PEP 561)


  • Fixed regression that required all noninjectable parameters to be typed


  • Added NewType support
  • Added type hints

Backwards incompatible:

  • Passing invalid parameter names to @noninjectable() will now result in an error
  • Dropped Python 3.3 support


  • Deprecated with_injector. There’s no one migration path recommended, it depends on a particular case.
  • Deprecated install_into.


  • Fixed a bug with classes deriving from PyQt classes not being able to be instantiated manually (bug #75, patch #76 thanks to David Pärsson)


  • Fixed a bug with values shared between Injectors in a hierarchy (bugs #52 and #72)
  • Binding scopes explicitly (Binder.bind_scope) is no longer necessary and bind_scope is a no-op now.


  • Improved some error messages


Backwards incompatible:

  • Dropped Python 3.2 support
  • Dropped Injector use_annotations constructor parameter. Whenever @inject is used parameter annotations will be used automatically.
  • Dropped Python 2 support (this includes PyPy)
  • Removed @provides decorator, use @provider instead
  • Removed support for passing keyword arguments to @inject


  • Fixed binding inference in presence of * and ** arguments (previously Injector would generate extra arguments, now it just ignores them)
  • Improved error reporting
  • Fixed compatibility with newer typing versions (that includes the one bundled with Python 3.6)

Technically backwards incompatible:


  • 0.11.0 packages uploaded to PyPI are broken (can’t be installed), this is a fix-only release.


  • The following way to declare dependencies is introduced and recommended now:

    class SomeClass:
        def __init__(self, other: OtherClass):
            # ...

    The following ways are still supported but are deprecated and will be removed in the future:

    # Python 2-compatible style
    class SomeClass
        def __init__(self, other):
            # ...
    # Python 3 style without @inject-decoration but with use_annotations
    class SomeClass:
        def __init__(self, other: OtherClass):
            # ...
    injector = Injector(use_annotations=True)
    # ...
  • The following way to declare Module provider methods is introduced and recommended now:

    class MyModule(Module):
        def provide_something(self, dependency: Dependency) -> Something:
            # ...

    @provider implies @inject.

    Previously it would look like this:

    class MyModule(Module):
        def provide_something(self, dependency: Dependency):
            # ...

    The provides() decorator will be removed in the future.

  • Added a noninjectable() decorator to mark parameters as not injectable (this serves as documentation and a way to avoid some runtime errors)

Backwards incompatible:

  • Removed support for decorating classes with @inject. Previously:

    class Class:


    class Class:
        def __init__(self, something: Something):
            self.something = something
  • Removed support for injecting partially applied functions, previously:

    def some_function(something):
    class Class:
        def __init__(self, function):
            # ...

    Now you need to move the function with injectable dependencies to a class.

  • Removed support for getting AssistedBuilder(callable=...)

  • Dropped Python 2.6 support

  • Changed the way AssistedBuilder and ProviderOf are used. Previously:

    builder1 = injector.get(AssistedBuilder(Something))
    # or: builder1 = injector.get(AssistedBuilder(interface=Something))
    builder2 = injector.get(AssistedBuilder(cls=SomethingElse))
    provider = injector.get(ProviderOf(SomeOtherThing))


    builder1 = injector.get(AssistedBuilder[Something])
    builder2 = injector.get(ClassAssistedBuilder[cls=SomethingElse])
    provider = injector.get(ProviderOf[SomeOtherThing])
  • Removed support for injecting into non-constructor methods


  • Fixed a false positive bug in dependency cycle detection (AssistedBuilder can be used to break dependency cycles now)


  • injector.Provider.get() now requires an injector.Injector instance as its parameter
  • deprecated injecting arguments into modules (be it functions/callables, Module constructors or injector.Module.configure() methods)
  • removed extends decorator
  • few classes got useful __repr__ implementations
  • fixed injecting ProviderOf and AssistedBuilders when injector.Injector auto_bind is set to False (previously would result in UnsatisfiedRequirement error)
  • fixed crash occurring when Python 3-function annotation use is enabled and __init__ method has a return value annotation (“injector.UnknownProvider: couldn’t determine provider for None to None”), should also apply to free functions as well


  • Bug fix release.


  • Child Injector can rebind dependancies bound in parent Injector (that changes Provider semantics), thanks to Ilya Orlov
  • CallableProvider callables can be injected into, thanks to Ilya Strukov
  • One can request ProviderOf (Interface) and get a BoundProvider which can be used to get an implementation of Interface when needed


  • Binding annotations are removed. Use Key() to create unique types instead.


  • Fixed regression with injecting unbound key resulting in None instead of raising an exception


  • Exception is raised when Injector can’t install itself into a class instance due to __slots__ presence
  • Some of exception messages are now more detailed to make debugging easier when injection fails
  • You can inject functions now - Injector provides a wrapper that takes care of injecting dependencies into the original function


  • Made AssistedBuilder behave more explicitly: it can build either innstance of a concrete class (AssistedBuilder(cls=Class)) or it will follow Injector bindings (if exist) and construct instance of a class pointed by an interface (AssistedBuilder(interface=Interface)). AssistedBuilder(X) behaviour remains the same, it’s equivalent to AssistedBuilder(interface=X)


  • Auto-convert to RST for PyPi.


  • Added a ChangeLog!
  • Added support for using Python3 annotations as binding types.