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Requirement for safety of cache_hash is stronger than documented #503

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rgabbard opened this Issue Feb 13, 2019 · 2 comments

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rgabbard commented Feb 13, 2019

The documentation states:

cache_hash (bool) – Ensure that the object’s hash code is computed only once and stored on the object. If this is set to True, hashing must be either explicitly or implicitly enabled for this class. If the hash code is cached, then no attributes of this class which participate in hash code computation may be mutated after object creation.

A reader could read this as meaning that only the local fields of this object should not be assigned to and that using this on any frozen class is okay. We should clarify that the object needs to be "deeply immutable" for this to be safe.

@rgabbard rgabbard self-assigned this Feb 13, 2019

@rgabbard rgabbard changed the title Require for safety of cache_hash is stronger than documented Requirement for safety of cache_hash is stronger than documented Feb 13, 2019

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hynek commented Feb 14, 2019

PR please? 😇

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rgabbard commented Feb 14, 2019

@hynek : Sure, I'll take care of this one sometime soon.

@hynek hynek added this to the 19.1.0 milestone Feb 14, 2019

@hynek hynek referenced this issue Feb 14, 2019

Merged

Clear cache hash on de-serialization #489

10 of 10 tasks complete

rgabbard added a commit to rgabbard/attrs that referenced this issue Feb 14, 2019

Clarify documentation for hashing
Makes clear that hashable objects need to be deeply immutable, in
practice even if not in theory.

Closes python-attrs#503 .

@hynek hynek closed this in #505 Feb 14, 2019

hynek added a commit that referenced this issue Feb 14, 2019

Improve documentation of safety constraints on hashable objects (#505)
* Clarify documentation for hashing

Makes clear that hashable objects need to be deeply immutable, in
practice even if not in theory.

Closes #503 .

* Use simple past tense in docs

bors bot added a commit to mozilla/normandy that referenced this issue Mar 4, 2019

Merge #1784
1784: Scheduled weekly dependency update for week 09 r=peterbe a=pyup-bot






### Update [attrs](https://pypi.org/project/attrs) from **18.2.0** to **19.1.0**.


<details>
  <summary>Changelog</summary>
  
  
   ### 19.1.0
   ```
   -------------------

Backward-incompatible Changes
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

- Fixed a bug where deserialized objects with ``cache_hash=True`` could have incorrect hash code values.
  This change breaks classes with ``cache_hash=True`` when a custom ``__setstate__`` is present.
  An exception will be thrown when applying the ``attrs`` annotation to such a class.
  This limitation is tracked in issue `494 &lt;https://github.com/python-attrs/attrs/issues/494&gt;`_.
  `482 &lt;https://github.com/python-attrs/attrs/issues/482&gt;`_


Changes
^^^^^^^

- Add ``is_callable``, ``deep_iterable``, and ``deep_mapping`` validators.

  * ``is_callable``: validates that a value is callable
  * ``deep_iterable``: Allows recursion down into an iterable,
    applying another validator to every member in the iterable
    as well as applying an optional validator to the iterable itself.
  * ``deep_mapping``: Allows recursion down into the items in a mapping object,
    applying a key validator and a value validator to the key and value in every item.
    Also applies an optional validator to the mapping object itself.

  You can find them in the ``attr.validators`` package.
  `425 &lt;https://github.com/python-attrs/attrs/issues/425&gt;`_
- Fixed stub files to prevent errors raised by mypy&#39;s ``disallow_any_generics = True`` option.
  `443 &lt;https://github.com/python-attrs/attrs/issues/443&gt;`_
- Attributes with ``init=False`` now can follow after ``kw_only=True`` attributes.
  `450 &lt;https://github.com/python-attrs/attrs/issues/450&gt;`_
- ``attrs`` now has first class support for defining exception classes.

  If you define a class using ``attr.s(auto_exc=True)`` and subclass an exception, the class will behave like a well-behaved exception class including an appropriate ``__str__`` method, and all attributes additionally available in an ``args`` attribute.
  `500 &lt;https://github.com/python-attrs/attrs/issues/500&gt;`_
- Clarified documentation for hashing to warn that hashable objects should be deeply immutable (in their usage, even if this is not enforced).
  `503 &lt;https://github.com/python-attrs/attrs/issues/503&gt;`_


----
   ```
   
  
</details>


 

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/attrs
  - Changelog: https://pyup.io/changelogs/attrs/
  - Homepage: https://www.attrs.org/
</details>





### Update [botocore](https://pypi.org/project/botocore) from **1.12.101** to **1.12.106**.


<details>
  <summary>Changelog</summary>
  
  
   ### 1.12.106
   ```
   ========

* api-change:``ec2``: Update ec2 client to latest version
* api-change:``autoscaling-plans``: Update autoscaling-plans client to latest version
   ```
   
  
  
   ### 1.12.105
   ```
   ========

* api-change:``ssm``: Update ssm client to latest version
* api-change:``apigatewayv2``: Update apigatewayv2 client to latest version
* api-change:``alexaforbusiness``: Update alexaforbusiness client to latest version
* api-change:``application-autoscaling``: Update application-autoscaling client to latest version
   ```
   
  
  
   ### 1.12.104
   ```
   ========

* api-change:``waf-regional``: Update waf-regional client to latest version
* api-change:``waf``: Update waf client to latest version
   ```
   
  
  
   ### 1.12.103
   ```
   ========

* api-change:``discovery``: Update discovery client to latest version
* api-change:``organizations``: Update organizations client to latest version
* api-change:``resource-groups``: Update resource-groups client to latest version
* api-change:``opsworkscm``: Update opsworkscm client to latest version
* api-change:``pinpoint``: Update pinpoint client to latest version
* api-change:``mediaconvert``: Update mediaconvert client to latest version
* api-change:``cur``: Update cur client to latest version
   ```
   
  
  
   ### 1.12.102
   ```
   ========

* api-change:``elbv2``: Update elbv2 client to latest version
* api-change:``mediastore``: Update mediastore client to latest version
* api-change:``ce``: Update ce client to latest version
* api-change:``autoscaling``: Update autoscaling client to latest version
   ```
   
  
</details>


 

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/botocore
  - Changelog: https://pyup.io/changelogs/botocore/
  - Repo: https://github.com/boto/botocore
</details>





### Update [cffi](https://pypi.org/project/cffi) from **1.12.1** to **1.12.2**.


*The bot wasn't able to find a changelog for this release. [Got an idea?](https://github.com/pyupio/changelogs/issues/new)*

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/cffi
  - Changelog: https://pyup.io/changelogs/cffi/
  - Docs: http://cffi.readthedocs.org
</details>





### Update [idna](https://pypi.org/project/idna) from **2.6** to **2.8**.


<details>
  <summary>Changelog</summary>
  
  
   ### 2.8
   ```
   ++++++++++++++++

- Update to Unicode 11.0.0.
- Provide more specific exceptions for some malformed labels.
   ```
   
  
  
   ### 2.7
   ```
   ++++++++++++++++

- Update to Unicode 10.0.0.
- No longer accepts dot-prefixed domains (e.g. &quot;.example&quot;) as valid.
  This is to be more conformant with the UTS 46 spec. Users should
  strip dot prefixes from domains before processing.
   ```
   
  
</details>


 

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/idna
  - Changelog: https://pyup.io/changelogs/idna/
  - Repo: https://github.com/kjd/idna
</details>





### Update [pyflakes](https://pypi.org/project/pyflakes) from **2.1.0** to **2.1.1**.


*The bot wasn't able to find a changelog for this release. [Got an idea?](https://github.com/pyupio/changelogs/issues/new)*

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/pyflakes
  - Changelog: https://pyup.io/changelogs/pyflakes/
  - Repo: https://github.com/PyCQA/pyflakes
</details>





### Update [google-api-core](https://pypi.org/project/google-api-core) from **1.7.0** to **1.8.0**.


*The bot wasn't able to find a changelog for this release. [Got an idea?](https://github.com/pyupio/changelogs/issues/new)*

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/google-api-core
  - Repo: https://github.com/GoogleCloudPlatform/google-cloud-python
</details>





### Update [google-cloud-core](https://pypi.org/project/google-cloud-core) from **0.28.1** to **0.29.1**.


*The bot wasn't able to find a changelog for this release. [Got an idea?](https://github.com/pyupio/changelogs/issues/new)*

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/google-cloud-core
  - Repo: https://github.com/GoogleCloudPlatform/google-cloud-python
</details>





### Update [protobuf](https://pypi.org/project/protobuf) from **3.6.1** to **3.7.0**.


*The bot wasn't able to find a changelog for this release. [Got an idea?](https://github.com/pyupio/changelogs/issues/new)*

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/protobuf
  - Changelog: https://pyup.io/changelogs/protobuf/
  - Repo: https://github.com/protocolbuffers/protobuf/releases
  - Homepage: https://developers.google.com/protocol-buffers/
</details>





### Update [boto3](https://pypi.org/project/boto3) from **1.9.101** to **1.9.106**.


<details>
  <summary>Changelog</summary>
  
  
   ### 1.9.106
   ```
   =======

* api-change:``ec2``: [``botocore``] Update ec2 client to latest version
* api-change:``autoscaling-plans``: [``botocore``] Update autoscaling-plans client to latest version
   ```
   
  
  
   ### 1.9.105
   ```
   =======

* api-change:``ssm``: [``botocore``] Update ssm client to latest version
* api-change:``apigatewayv2``: [``botocore``] Update apigatewayv2 client to latest version
* api-change:``alexaforbusiness``: [``botocore``] Update alexaforbusiness client to latest version
* api-change:``application-autoscaling``: [``botocore``] Update application-autoscaling client to latest version
   ```
   
  
  
   ### 1.9.104
   ```
   =======

* api-change:``waf-regional``: [``botocore``] Update waf-regional client to latest version
* api-change:``waf``: [``botocore``] Update waf client to latest version
   ```
   
  
  
   ### 1.9.103
   ```
   =======

* api-change:``discovery``: [``botocore``] Update discovery client to latest version
* api-change:``organizations``: [``botocore``] Update organizations client to latest version
* api-change:``resource-groups``: [``botocore``] Update resource-groups client to latest version
* api-change:``opsworkscm``: [``botocore``] Update opsworkscm client to latest version
* api-change:``pinpoint``: [``botocore``] Update pinpoint client to latest version
* api-change:``mediaconvert``: [``botocore``] Update mediaconvert client to latest version
* api-change:``cur``: [``botocore``] Update cur client to latest version
   ```
   
  
  
   ### 1.9.102
   ```
   =======

* api-change:``elbv2``: [``botocore``] Update elbv2 client to latest version
* api-change:``mediastore``: [``botocore``] Update mediastore client to latest version
* api-change:``ce``: [``botocore``] Update ce client to latest version
* api-change:``autoscaling``: [``botocore``] Update autoscaling client to latest version
   ```
   
  
</details>


 

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/boto3
  - Changelog: https://pyup.io/changelogs/boto3/
  - Repo: https://github.com/boto/boto3
</details>





### Update [django-cors-headers](https://pypi.org/project/django-cors-headers) from **2.4.0** to **2.4.1**.


<details>
  <summary>Changelog</summary>
  
  
   ### 2.4.1
   ```
   ------------------

* Fix ``DeprecationWarning`` from importing ``collections.abc.Sequence`` on
  Python 3.7.
   ```
   
  
</details>


 

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/django-cors-headers
  - Changelog: https://pyup.io/changelogs/django-cors-headers/
  - Repo: https://github.com/ottoyiu/django-cors-headers
</details>





### Update [django-mozilla-product-details](https://pypi.org/project/django-mozilla-product-details) from **0.13** to **0.13.1**.


*The bot wasn't able to find a changelog for this release. [Got an idea?](https://github.com/pyupio/changelogs/issues/new)*

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/django-mozilla-product-details
  - Repo: https://github.com/mozilla/django-product-details/
</details>





### Update [djangorestframework](https://pypi.org/project/djangorestframework) from **3.9.1** to **3.9.2**.


*The bot wasn't able to find a changelog for this release. [Got an idea?](https://github.com/pyupio/changelogs/issues/new)*

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/djangorestframework
  - Changelog: https://pyup.io/changelogs/djangorestframework/
  - Homepage: https://www.django-rest-framework.org/
</details>





### Update [jsonschema](https://pypi.org/project/jsonschema) from **3.0.0** to **3.0.1**.


*The bot wasn't able to find a changelog for this release. [Got an idea?](https://github.com/pyupio/changelogs/issues/new)*

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/jsonschema
  - Changelog: https://pyup.io/changelogs/jsonschema/
  - Repo: https://github.com/Julian/jsonschema
</details>





### Update [pytest-django](https://pypi.org/project/pytest-django) from **3.4.7** to **3.4.8**.


<details>
  <summary>Changelog</summary>
  
  
   ### 3.4.8
   ```
   ------------------

Bugfixes
^^^^^^^^

* Fix DB renaming fixture for Multi-DB environment with SQLite (679)
   ```
   
  
</details>


 

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/pytest-django
  - Changelog: https://pyup.io/changelogs/pytest-django/
  - Docs: https://pytest-django.readthedocs.io/
</details>





### Update [google-cloud-storage](https://pypi.org/project/google-cloud-storage) from **1.13.0** to **1.14.0**.


*The bot wasn't able to find a changelog for this release. [Got an idea?](https://github.com/pyupio/changelogs/issues/new)*

<details>
  <summary>Links</summary>
  
  - PyPI: https://pypi.org/project/google-cloud-storage
  - Repo: https://github.com/GoogleCloudPlatform/google-cloud-python
</details>







Co-authored-by: pyup-bot <github-bot@pyup.io>
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