Re: [RFC/PATCH] pathspec: allow escaped query values

[Ramsay Jones <ramsay@ramsayjones.plus.com>]

On 02/06/16 17:10, Junio C Hamano wrote:
> Ramsay Jones <ramsay@ramsayjones.plus.com> writes:
> 
>> So, at risk of annoying you, let me continue in my ignorance a little
>> longer and ask: even if you have to protect all of this 'magic' from
>> the shell with '/" quoting, could you not use (nested) quotes to
>> protect the <value> part of an <attr>? For example:
>>
>>     git ls-files ':(attr:whitespace="indent,trail,space",icase)'
> 
> That would be workable, I would think.  Before attr:VAR=VAL
> extention, supported pathspec <magic> were only single lowercase-ascii
> alphabet tokens, so nobody would have used " as a part of magic.  So
> quting with double-quote pair would work.

I was thinking about both ' and ", so that you could do:

   $ ./args ':(attr:whitespace="indent,trail,space",icase)'
    1::(attr:whitespace="indent,trail,space",icase)

   $ ./args ":(attr:whitespace='indent,trail,space',icase)"
    1::(attr:whitespace='indent,trail,space',icase)

   $ p=':(attr:whitespace="indent,trail,space",icase)'
   $ ./args "$p"
    1::(attr:whitespace="indent,trail,space",icase)

   $ p=":(attr:whitespace=\"indent,trail,space\",icase)"
   $ ./args "$p"
    1::(attr:whitespace="indent,trail,space",icase)

but limiting it to " would probably be OK too.

> You'd need to come up with a way to quote a double quote that
> happens to be a part of VAL somehow, though.

Yes I was assuming \ quoting as well - I just want to reduce the
need for such quoting (especially on windows).

>                                              I think attribute
> value is limited to a string with non-whitespace letters; even
> though the built-in attributes that have defined meaning to the Git
> itself may not use values with letters beyond [-a-zA-Z0-9,], end
> users and projects can add arbitrary values within the allowed
> syntax, so it is not unconceivable that some project may have a
> custom attribute that lists forbidden characters in a path with
> 
> 	=== .gitattributes ===
>         *.txt forbidden=`"
> 
> that tells their documentation cannot have these letters in it, or
> something like that.

Heh, yeah, that gets ugly:

   $ ./args ":(attr:*.txt forbidden=\'\\\",icase)"
    1::(attr:*.txt forbidden=\'\",icase)

   $ ./args ':(attr:*.txt forbidden=\'\''\",icase)'
    1::(attr:*.txt forbidden=\'\",icase)

[Note the initial ' 1:' above is output from args]

ATB,
Ramsay Jones