Re: Review of git multimail

[Michael Haggerty <mhagger@alum.mit.edu>]

On 07/03/2013 12:21 AM, Junio C Hamano wrote:
> Ramkumar Ramachandra <artagnon@gmail.com> writes:
> 
>>>     def get(self, name, default=''):
>>>         try:
>>>             values = self._split(read_git_output(
>>>                     ['config', '--get', '--null', '%s.%s' % (self.section, name)],
>>>                     env=self.env, keepends=True,
>>>                     ))
>>
>> Wait, what is the point of using --null and then splitting by hand
>> using a poorly-defined static method?  Why not drop the --null and
>> splitlines() as usual?
> 
> You may actually have spotted a bug or misuse of "--get" here.
> 
> With this sample configuration:
> 
>         $ cat >sample <<\EOF
>         [a]
>                 one = value
>                 one = another
> 
>         [b]
>                 one = "value\nanother"
>         EOF
> 
> A script cannot differentiate between them without using '--null'.
> 
> 	$ git config -f sample --get-all a.one
>         $ git config -f sample --get-all b.one
> 
> But that matters only when you use "--get-all", not "--get".  If
> this method wants to make sure that the user did not misuse a.one
> as a multi-valued configuration variable, use of "--null --get-all"
> followed by checking how many items the command gives you back would
> be a way to do so.

No, the code in question was a simple sanity check (i.e., mostly a check
of my own sanity and understanding of "git config" behavior) preceding
the information-losing next line "return values[0]".  If it had been
meant as a check that the user hadn't misconfigured the system, then I
wouldn't have used assert but rather raised a ConfigurationException
with an explanatory message.

I would be happy to add the checking that you described, but I didn't
have the impression that it is the usual convention.  Does code that
wants a single value from the config usually verify that there is
one-and-only-one value, or does it typically just do the equivalent of
"git config --get" and use the returned (effectively the last) value?

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu
http://softwareswirl.blogspot.com/