Failure.parents has duplicate class

[lvh]

In #4928, amaury commented that twisted.python.failure.Failure.parents now contains the initial class twice. This is not a real correctness problem, but it's a bit stupid and inefficient.

[retenodus]

Patch to remove duplicate class of Failure.parents

[retenodus]

getmro already returns the type, so the line isn't necessary.

[dustin]

This is very straightforward - presumably this error was introduced in the switch from allYourBase to getmro, where the former does not return the given class, and the latter does. I'm tempted to say that this should have tests to verify that the the behavior has changed appropriately, but that seems like overkill here.

The existing tests continue to pass for me. Please merge.

[dustin]

Er, this also needs a topfiles addition - so do not merge yet!

[retenodus]

Euh, what topfile ?

I can't merge, the doc says that a core developper will merge it.

[exarkun]

The topfile can be a .misc for this change I think. I'll add it and apply the patch now. Thanks for your work on this retenodus, and for the review dustin.

[exarkun]

Ah, also, just to clarify one point. I agree that we don't need a unit test here - because the patch is a pure deletion. Generally it's okay to delete code without adding new tests, as long as some executing tests are executing the code being changed (if no tests had previously been running the if suite including the change, then a new test probably would have been required).

[exarkun]

(In [32306]) Remove duplicate exception from Failure.parents

Author: retenodus Reviewer: dustin Fixes: #4957

When twisted/python/failure.py switched from allYourBase to inspect.getmro, a duplicate of the type of failure.value was introduced into failure.parents. Remove it.