Fix param name to match the doc in SelectorList.xpath()

[laggardkernel]

Trivial typo spotted during reading the source code.

Replace param xpath in SelectorList.xpath() with name query to match the name used in the doc and Selector.xpath().

class SelectorList(list):
    ...
-    def xpath(self, xpath, namespaces=None, **kwargs):
+    def xpath(self, query, namespaces=None, **kwargs):
        """
        ...
        ``query`` is the same argument as the one in :meth:`Selector.xpath`
        ...
        """
-        return self.__class__(flatten([x.xpath(xpath, namespaces=namespaces, **kwargs) for x in self]))
+        return self.__class__(flatten([x.xpath(query, namespaces=namespaces, **kwargs) for x in self]))
    ...

class Selector(object):
    ...
    def xpath(self, query, namespaces=None, **kwargs):
        ...

[codecov]

Codecov Report

Merging #220 (7cab4ce) into master (80509e4) will decrease coverage by 1.64%.
The diff coverage is 37.50%.

❗ Current head 7cab4ce differs from pull request most recent head 9621c01. Consider uploading reports for the commit 9621c01 to get more accurate results

@@             Coverage Diff             @@
##            master     #220      +/-   ##
===========================================
- Coverage   100.00%   98.35%   -1.65%     
===========================================
  Files            5        5              
  Lines          298      304       +6     
  Branches        51       53       +2     
===========================================
+ Hits           298      299       +1     
- Misses           0        4       +4     
- Partials         0        1       +1     

Impacted Files	Coverage Δ
parsel/selector.py	96.91% <37.50%> (-3.09%)	⬇️

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[Gallaecio]

The issue with this change is that it breaks backward compatibility if the parameter is specified with a keyword (i.e. .xpath(xpath=…)).

What about making the parameter query=None, then doing query = query or kwargs.pop('xpath', None), and finally raising an exception about a parameter being missing if query is still None at that point?

[laggardkernel]

@Gallaecio I thought for a while about the compatibility thing before pushing this pr. Considering it's a trivial change, I just ignored the backward compatibility support.

What about this one with backward compatibility support and deprecation warning? laggardkernel/parsel@6fa4867

[Gallaecio]

What about this one with backward compatibility support and deprecation warning? laggardkernel/parsel@6fa4867

I have minor feedback, mostly style-related, but I think that’s the best approach, yes.

[laggardkernel]

@Gallaecio Thanks for the advice about the code style. I applied them and force pushed the commit to this PR.

[Gallaecio]

Ideally, we should have a test for the fix, i.e. test that passing query= works, that xpath= logs a warning, and that None raises a ValueError.

I do wonder what was the behavior before when passing None as xpath. If that did not raise a ValueError before, we may need to adapt to whatever the behavior was.