Re: [PATCH v4 2/2] sequencer: fix quoting in write_author_script

[Phillip Wood <phillip.wood@talktalk.net>]

Hi Eric

On 07/08/18 11:23, Eric Sunshine wrote:
> On Tue, Aug 7, 2018 at 5:35 AM Phillip Wood <phillip.wood@talktalk.net> wrote:
>>      - Reverted the implementation to v2 with more robust detection of the
>>        missing "'" on the last line of the author script based on a
>>        suggestion by Eric. This means that this series needs to progress
>>        closely with Eric's series of fixes or the fallback code will never
>>        be called.
> 
> Thanks for working on this. I haven't read the patch closely yet, but
> one thing caught my attention as I ran my eye over it...
> 
>> +static int quoting_is_broken(const char *s, size_t n)
>> +{
>> +       /* Skip any empty lines in case the file was hand edited */
>> +       while (n > 0 && s[--n] == '\n')
>> +               ; /* empty */
>> +       if (n > 0 && s[n] != '\'')
>> +               return 1;
> 
> To be "technically correct", I think the condition in the 'if'
> statement should be ">=". It should never happen in practice that the
> entire content of the file is a single character followed by zero or
> more newlines, but using the proper condition ">=" would save future
> readers of this code a "huh?" moment.
> 

I'm not sure it is that simple. If the script consists solely of a
single quote then we should return 1, if it is a single character that
is not "'" then it should return 0. Currently it returns 0 in both those
cases so is technically broken when the script is "'". If it used ">="
instead then I think it would return 0 when it should return 1 and vice
versa. As you say this shouldn't happen in practice.

Best Wishes

Phillip