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Temporary metaclass should not inherit from "meta" #191

Merged
merged 1 commit into from
Sep 17, 2017
Merged

Temporary metaclass should not inherit from "meta" #191

merged 1 commit into from
Sep 17, 2017

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jdemeyer
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In the current implementation of with_metaclass, the temporary metaclass inherits from meta. Later we call type.__new__(metaclass, ...). This can lead to errors of the form

type.__new__(metaclass) is not safe, use ....__new__()

if meta is an extension type instead of a plain Python class.

Since I see no reason for inheriting from meta, this patch fixes that to inherit from the base class type instead.

@benjaminp benjaminp merged commit 024fcbb into benjaminp:master Sep 17, 2017
benjaminp added a commit that referenced this pull request Sep 17, 2017
@benjaminp
changelog for pr #191
a3b7706
@dghubble dghubble mentioned this pull request Sep 18, 2017
Closed
@jdemeyer jdemeyer deleted the with_metaclass branch September 18, 2017 07:51
jmoldow added a commit to box/box-python-sdk that referenced this pull request Sep 18, 2017
@jmoldow
Fix some issues with six dependency
9c21053 
Add a fallback for `six.raise_from`, which isn't available in
six 1.4.0. It isn't available until six 1.9.0. We could also
have raised the lower bound for the six requirement, but this is
an easy way to allow clients to keep using their existing
versions of six.

Fix support for the latest version of six, 1.11.0. That release
changed the temporary metaclass returned from
`with_metaclass()`, such that it directly inherits from `type`,
instead of inheriting from the target metaclass [1]. We depended
on this detail, and the change caused

.. code-block:: python

    TypeError('metaclass conflict: ...')

to be raised when defining a class with `with_metaclass()`. We
fix this by manually selecting the most derived metaclass, and
including it in our temporary metaclass.

Also, `__prepare__` is now defined on the temporary metaclass,
in six 1.11.0 [2]. This allows us to skip our own definition of that
method, when using six>=1.11.0.

Fixes #228.

Fixes #239.

[1] <benjaminp/six#191>
[2] <benjaminp/six#178>
jmoldow added a commit to box/box-python-sdk that referenced this pull request Sep 18, 2017
@jmoldow
Fix some issues with six dependency
d8e35da 
Add a fallback for `six.raise_from`, which isn't available in
six 1.4.0. It isn't available until six 1.9.0. We could also
have raised the lower bound for the six requirement, but this is
an easy way to allow clients to keep using their existing
versions of six.

Fix support for the latest version of six, 1.11.0. That release
changed the temporary metaclass returned from
`with_metaclass()`, such that it directly inherits from `type`,
instead of inheriting from the target metaclass [1]. We depended
on this detail, and the change caused

.. code-block:: python

    TypeError('metaclass conflict: ...')

to be raised when defining a class with `with_metaclass()`. We
fix this by manually selecting the most derived metaclass, and
including it in our temporary metaclass.

Also, `__prepare__` is now defined on the temporary metaclass,
in six 1.11.0 [2]. This allows us to skip our own definition of that
method, when using six>=1.11.0.

Fixes #228.

Fixes #239.

[1] <benjaminp/six#191>
[2] <benjaminp/six#178>
@jmoldow jmoldow mentioned this pull request Sep 18, 2017
Merged
jmoldow added a commit to box/box-python-sdk that referenced this pull request Sep 18, 2017
@jmoldow
Fix some issues with six dependency
a03a5bf 
Add a fallback for `six.raise_from`, which isn't available in
six 1.4.0. It isn't available until six 1.9.0. We could also
have raised the lower bound for the six requirement, but this is
an easy way to allow clients to keep using their existing
versions of six.

Fix support for the latest version of six, 1.11.0. That release
changed the temporary metaclass returned from
`with_metaclass()`, such that it directly inherits from `type`,
instead of inheriting from the target metaclass [1]. We depended
on this detail, and the change caused

.. code-block:: python

    TypeError('metaclass conflict: ...')

to be raised when defining a class with `with_metaclass()`. We
fix this by manually selecting the most derived metaclass, and
including it in our temporary metaclass.

Also, `__prepare__` is now defined on the temporary metaclass,
in six 1.11.0 [2]. This allows us to skip our own definition of that
method, when using six>=1.11.0.

Fixes #228.

Fixes #239.

[1] <benjaminp/six#191>
[2] <benjaminp/six#178>
@jmoldow jmoldow mentioned this pull request Sep 18, 2017
Merged
jmoldow added a commit to box/box-python-sdk that referenced this pull request Sep 19, 2017
@jmoldow
Fix some issues with six dependency (#240)
e65d34c 
Update minimum required version of `six` to 1.9.0, so that
`six.raise_from` can be safely used by all clients.

Fix support for the latest version of six, 1.11.0. That release
changed the temporary metaclass returned from
`with_metaclass()`, such that it directly inherits from `type`,
instead of inheriting from the target metaclass [1]. We depended
on this detail, and the change caused

.. code-block:: python

    TypeError('metaclass conflict: ...')

to be raised when defining a class with `with_metaclass()`. We
fix this by manually selecting the most derived metaclass, and
including it in our temporary metaclass.

Also, `__prepare__` is now defined on the temporary metaclass,
in six 1.11.0 [2]. This allows us to skip our own definition of that
method, when using six>=1.11.0.

Fixes #228.

Fixes #239.

[1] <benjaminp/six#191>
[2] <benjaminp/six#178>
jmoldow added a commit to box/box-python-sdk that referenced this pull request Sep 19, 2017
@jmoldow
Fix some issues with six dependency (#241)
ad58f15 
Add a fallback for `six.raise_from`, which isn't available in
six 1.4.0. It isn't available until six 1.9.0. We could also
have raised the lower bound for the six requirement, but this is
an easy way to allow clients to keep using their existing
versions of six.

Fix support for the latest version of six, 1.11.0. That release
changed the temporary metaclass returned from
`with_metaclass()`, such that it directly inherits from `type`,
instead of inheriting from the target metaclass [1]. We depended
on this detail, and the change caused

.. code-block:: python

    TypeError('metaclass conflict: ...')

to be raised when defining a class with `with_metaclass()`. We
fix this by manually selecting the most derived metaclass, and
including it in our temporary metaclass.

Also, `__prepare__` is now defined on the temporary metaclass,
in six 1.11.0 [2]. This allows us to skip our own definition of that
method, when using six>=1.11.0.

Fixes #228.

Fixes #239.

[1] <benjaminp/six#191>
[2] <benjaminp/six#178>
@mkurek mkurek mentioned this pull request Nov 7, 2017
Closed
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2 participants
@jdemeyer @benjaminp