[code-quality] Error codes (Was: Pyflakes forked to Frosted)

[Ian Cordasco]

On Sun, Jan 19, 2014 at 11:12 AM, Kay Hayen <kay.hayen at gmail.com> wrote:
> Hello,
>
> this was interesting to me:
>
>> Error numbers in tools such as pep8 and pyflakes (although flake8 adds
>> them to pyflakes) are usually not made to be entirely successive. For
>> the most part, there are groupings of errors. The best explanation of
>> this is pep8's documentation:
>> http://pep8.readthedocs.org/en/latest/intro.html#error-codes
>>
>> Anything starting with E1 is related to indentation, anything starting
>> with E2 is related to whitespace. These are conceptually classes of
>> errors. PyLint also follows this convention if I remember correctly
>> and you would do well to do the same. The error codes that Flake8 adds
>> to PyFlakes follow that convention as well.
>
>
> So for my compiler Nuitka, there are very few warnings so far, mostly
> because
> it is very limited in its tracing abilities, but I am expanding this now,
> and so far
> I was kind of clueless on how to properly format error and warning messages.
>
> It probably will a while, before I find the need to expand it, but it would
> be good
> to have a common ground, reusable data. For PyLint, these texts seem spread
> out in the variables files.

You would do best to research (and possibly revive) past conversations
on this list about a standardization of error messages. I believe the
standard that Flake8 uses is also pep8's format (which is similar to
PyLint). pep257 also has a rewrite branch to use that format. Trying
to create a standard about something so subjective is difficult and it
becomes more difficult when tools like pep8 support providing your own
formatter.

> Is there an easy way to access the PyLint warning/error message texts.

I would hope so, but I do not personally know.

> Would you be OK with me to grep these out of PyLint or Wiki, and use them under
> ASF2
> in my project as well. I would of course prefer, for these to exist a place
> that makes
> reuse easier.

I cannot grant you permission to do this because I am not associated
with the project. For others reading the list, the ASF2 refers to
https://www.apache.org/licenses/LICENSE-2.0, also known as the Apache
License 2.0. I'm also a bit fuzzy on the compatibility of the LGPL2.1
with Apache 2.0. I'm also not entirely certain how PyLint's error
codes would benefit your project.

> Basically, I am saying, why isn't this some kind of standard. And can we
> make it
> one.

Standardizing anything is difficult. People rarely agree on anything.
One way to achieve your standard, however, may be to write a package
(ideally permissively licensed like Nuitka) that provides formatters
for the more popular options, i.e., pep8 and pyflakes. Then simply
encourage those writing similar tools to use that to reduce code
duplication and possible errors. If your module achieves enough
popularity, it would then become a de facto standard rather than a
standard designed by committee.

Further, you seem to be conflating ideas:

- Message/warning formatting
- Error code design

The former deals with how the message is printed, while the latter is
far more semantic in how error codes are assigned. The latter will be
far harder to codify than even the former. Again a module to help with
this may work but I would guess that people will be less inclined to
use it than a module which formats the messages for them.

Cheers,
Ian