[jira] Updated: (THRIFT-162) Thrift structures are unhashable, preventing them from being used as set elements

["Bryan Duxbury (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/THRIFT-162?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Bryan Duxbury updated THRIFT-162:
---------------------------------

    Fix Version/s:     (was: 0.4)

I'm untagging this for 0.4 because I don't expect it to get done today, but I'd really love it if someone who understands the final state of this issue were to figure it out and either commit it or let me know so I can commit it.

> Thrift structures are unhashable, preventing them from being used as set elements
> ---------------------------------------------------------------------------------
>
>                 Key: THRIFT-162
>                 URL: https://issues.apache.org/jira/browse/THRIFT-162
>             Project: Thrift
>          Issue Type: Bug
>          Components: Compiler (Python), Library (Python)
>            Reporter: Esteve Fernandez
>            Priority: Minor
>         Attachments: immut-no-slots-v1.diff, immut-v2.diff, immut-v3.diff, immut-v4.diff, reading-containers.diff, thrift-162_annotiations.patch, thrift-162_v2_annotiations.patch, thrift_py_hash.patch
>
>
> Let Foo be a Thrift structure:
> struct Foo {
>  1: i32 bar
> }
> If you want to use it properly as a set element or a as a dictionary key, the autoegenerated Python code will complain about not being hashable:
> >>> f1 = Foo()
> >>> f1.bar = 1
> >>> f2 = Foo()
> >>> f2.bar = 1
> >>> f1 == f2
> True
> >>> set([f1]) & set([f2])
> set([])
> >>> d = {}
> >>> d[f1] = 2
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
> TypeError: unhashable instance
> Since Thrift structures already implement __eq__ and __ne__, they should implement __hash__ as well. The attached patch tries to mimic the behaviour of the Java compiler, including a HashCodeBuilder class written in Python.

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