Useless assertion in twisted.web.microdom.Node.replaceChild

[exarkun]

The assertion is always positive. Plus asserts are almost always pointless.

[jparise]

Corrects assert syntax

[jparise]

The attached patch corrects the syntax of the offending assert statement. This assert now functions as intended and no longer generates warnings under Python 2.6+. There should be no other behavioral differences.

[exarkun]

Asserts are silly. Can you instead change it to an explicit check which raises some documented interface and add a unit test for the behavior?

[jparise]

Replaces asserts with exceptions

[jparise]

I've attached a new patch that replaces a handful of assertions with exceptions. The unit test has been updated, and the exceptions are documented in the methods' docstrings.

There are still some remaining assertions in microdom.py that could also be replaced with exceptions. Those cases are more "interesting", however, as they would benefit most from custom exception classes given their microdom-ish-specific nature. If there's a desire to convert those as well, it might be best to track that work under a separate ticket.

[jparise]

Adding the Python-2.6 milestone because the current trunk code produces a warning under Python 2.6.

[exarkun]

(In [25490]) Branching to 'microdom-assert-3421'

[exarkun]

(In [25491]) apply microdom.assert2.diff

refs #3421

[exarkun]

(In [25493]) split replaceChild ValueError test into separate method

refs #3421

[exarkun]

(In [25494]) remove useless dom parent fakes

refs #3421

[exarkun]

(In [25495]) raise ValueError from Document.appendChild if there are too many children

refs #3421

[exarkun]

(In [25496]) some docstrings

refs #3421

[exarkun]

thanks jparise.

I've made a few more changes in the branch. Someone else should take a look at this now.

[mwh]

The exception in the branch make more sense than the assertions in trunk. They're still not very good, as they don't really provide much help in fixing your problem (like, what type was it if it wasn't a Node? For replaceChild, which parameter was it?).

OTOH, microdom is on it's way out anyway (right?), so I don't see much point in expending effort in fixing the above.

Land the branch, IOW.

[exarkun]

(In [25554]) Merge microdom-assert-3421

Author: jparise, exarkun Reviewer: exarkun, mwhudson Fixes: #3421

Remove most asserts from microdom and replace them with checks which raise some documented exception. In particular, remove one assertion which could never fail and which produced a warning on Python 2.6.