Re: true,false: --version,--help exit code

[Pádraig Brady]

On 06/03/2014 03:41 PM, Jim Meyering wrote:
> On Tue, Jun 3, 2014 at 7:23 AM, Jim Meyering <address@hidden> wrote:
>> On Tue, Jun 3, 2014 at 5:16 AM, Pádraig Brady <address@hidden> wrote:
>>> On 06/03/2014 01:12 PM, Eric Blake wrote:
>> ...
>>>> Oh, good point.  Maybe it's better to consistently have --help/--version
>>>> return status 0 (we successfully printed output) or 1 (we encountered
>>>> write failure) regardless of the program being executed (which means
>>>> true is doing it right, and 'false --version' is the odd man out,
>>>> opposite to what the most recent patch proposal does).  I'd wait for
>>>> Paul and/or Jim to weigh in on this, since they made the decisions
>>>> behind the current unpatched behavior.
>>>
>>> My slight preference is to change true to be consistent,
>>> as then it's consistent on all implementations, not
>>> just within coreutils. I.E. the following would now hold everywhere:
>>>
>>>   true --help > /dev/full && echo always ok
>>
>> My rationale in making true --help > /dev/full diagnose the error was
>> to consistently enable detection of write failure.  With --help and
>> --version, we are outside the bounds of POSIX spec. The amended
>> spec is that the program must print the requested output and exit
>> with status reflecting success or failure of the write. Without that
>> check, someone attempting to write-then-parse that help output
>> would be unable to distinguish the successful case and one in which
>> the write hit e.g., EIO or ENOSPC.
>>
>> IMHO, there is no reason to ignore such a write error.
>> Hence, false --version and false --help (currently always failing) are the
>> ones I would change, so that they succeed when there is no write error.
> 
> On second thought, I don't like the idea of making false --help/--version
> exit successfully.
> 
> Maybe, gasp, we should just make true and false the exception from
> GNU's accept --help/--version philosophy, and simply exit 0/1, ignoring
> *all* options. This would add minor complication to true.1 and false.1
> man page generation, but it would not be hard to work around.

Or just leave it as is?
I.E. true can return false in the edge cases where it needs to.

I can fix up the test issues I noticed separately.

thanks,
Pádraig.