RFC: Document unexpected behaviour of --fatal-warnings

[Jan Beulich]

On 23.01.2024 13:28, Nick Clifton wrote:
> Hi Guys,
> 
>   It was recently pointed out to me that the bfd linker's
>   --fatal-warnings option can behave in an unexpected manner.  For
>   example:
> 
>     $ ld.bfd -z bad-option --fatal-warnings -e 0/dev/null
>     ld.bfd: warning: -z bad-option ignored
>     $ echo $?
>     0
> 
>   ie the warning about the ignored option is not being treated as an
>   error.  This happens because the --fatal-warnings option only takes
>   affect after it has been processed, and we process the options in a
>   linear order.  So the following works:
> 
>     $ ld.bfd --fatal-warnings -z bad-option -e 0 /dev/null
>     ld.bfd: warning: -z bad-option ignored
>     $ echo $?
>     1
> 
>   This behaviour differs from gold and lld, both of which honour
>   --fatal-warnings no matter where it occurs on the command line.
> 
>   So we could fix the linker, create a two pass argument scan and the
>   problem would be solved.  But a) I am lazy and b) we already have a
>   precedent for options on the command line only affecting options that
>   come after it.  (I am thinking of the -L option here, although there
>   are probably several others).  So instead I am considering documenting
>   the current behaviour as expected.  (See the patch below).
> 
>   What do people think ?

I'd be fine either way, and I agree documenting is cheaper and sufficient.

Jan