PyChecker messages

[Eric Brunel]

Frans Englich wrote:
> Hello,
> 
> I take PyChecker partly as an recommender of good coding practice, but I 
> cannot make sense of some of the messages. For example:
> 
> runner.py:878: Function (main) has too many lines (201)
> 
> What does this mean? Cannot functions be large? Or is it simply an advice that 
> functions should be small and simple?

This is an advice. You can set the number after which the warning is triggered 
via the maxLines option in your .pycheckrc file.

> runner.py:200: Function (detectMimeType) has too many returns (11)
> 
> The function is simply a long "else-if" clause, branching out to different 
> return statements. What's wrong? It's simply a "probably ugly code" advice?

Same thing; the corresponding option in .pycheckrc is maxReturns. Other options 
that may interest you are maxBranches, maxArgs, maxLocals and maxReferences. 
Please see PyChecker's documentation for more details.

> A common message is these:
> 
> runner.py:41: Parameter (frame) not used
> 
> But I'm wondering if there's cases where this cannot be avoided. For example, 
> this signal handler:
> 
> #-------------------------------------------
> def signalSilencer( signal, frame ):
>     """
>     Dummy signal handler for avoiding ugly
>     tracebacks when the user presses CTRL+C.
>     """
>     print "Received signal", str(signal) + ", exiting."
>     sys.exit(1)
> #-------------------------------------------
> 
> _must_ take two arguments; is there any way that I can make 'frame' go away?

See/set the unusedNames option in .pycheckrc; this is a list of names for which 
this kind of warnings are not triggered. If you set for example:

unusedNames = [ 'dummy' ]

in .pycheckrc and if you define your function with:

def signalSilencer(signal, dummy):
   ...

the warning will not be triggered.

BTW, if your signal handler is just here to catch Ctrl-C, you'd better do a 
try/except on KeyboardInterrupt...

HTH
-- 
- Eric Brunel <eric (underscore) brunel (at) despammed (dot) com> -
PragmaDev : Real Time Software Development Tools - http://www.pragmadev.com