Re: shopt compat

[Chet Ramey]

On 8/14/24 2:25 AM, Martin Kealey wrote:
> Hi Chet
>
> I have worked up a patch that considerably simplifies the logic for
> setting and displaying the shopt compatXX settings, by getting rid of
> the numberous boolean variables and simply computing the setting level
> directly.

Thanks. The boolean variables and corresponding shopt options are frozen
and only remain for backwards compatibility; there are no compatXX shopt
options beyond compat44; the BASH_COMPAT variable is the current way to
set the compatibility level.

> However before I submit my compatXX patch, I would like to ensure I've
> correctly accounted for the intention of the commit below, which I
> assume is fairly described by this comment:
>
> > If we're unsetting one of the compatibility options, make sure the
> > current value is in the range of the compatNN space.
>
> In partiular, I'm puzzled by the introduction of this boolean expression
>
> > (oldval > 44 && shell_compatibility_level < DEFAULT_COMPAT_LEVEL)

There are no compat options beyond compat44, so any value greater than
that must have been set via BASH_COMPAT.

> For example, once it's possible to use 'shopt -s compat52', we would then
> find that 'shopt -u compat52' would have no effect, unless the number
> "44" is updated to match any new available levels.

We're not going to do that.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

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