Geoff Clare wrote, on 19 Aug 2020:
>
> > ----------------------------------------------------------------------
> > (0004926) geoffclare (manager) - 2020-08-19 09:22
> > https://austingroupbugs.net/view.php?id=1392#c4926
> > ----------------------------------------------------------------------
>
> > I think we should issue a "standard is silent" interpretation, thus
> > allowing both behaviours for Issue 7, but we should make a change in Issue
> > 8 to require the BSD behaviour.
>
> I started looking into a wording change for this, but I'm not too
> keen on where it would end up. It would have a particular difference
> from chmod that would "stick out like a sore thumb", which is that
> when '=' is used without a "who", find ignores the umask but chmod
> uses it.
>
> Is that what BSD find does? Or is it consistent with chmod here
> (contrary to what the standard requires)?
This got answered via a bug note (4941): macOS (which uses BSD find)
is consistent with chmod.
> Perhaps we should allow the difference but recommend against it.
I think I would prefer just to require consistency with chmod in Issue 8.
The difference from chmod violates the principle of least surprise.
Another reason to disallow ignoring the umask for '=' without a "who"
is that this makes it identical to 'a=', thus reducing the available
functionality for no reason.
I propose:
The <i>mode</i> argument is used to represent file mode bits. It shall
be processed in an identical matter to the <i>symbolic_mode</i> operand
described in <i>chmod</i>, except that:
1. The changes to file mode bits shall be applied to a template instead
of to any files. The template shall initially have all file mode
bits cleared.
2. The <i>op</i> symbol '-' cannot be the first character of <i>mode</i>;
this avoids ambiguity with the optional leading <hyphen-minus>. Since
the initial mode is all bits off, there are not any symbolic modes
that need to use '-' as the first character.
If the <hyphen-minus> is omitted, ...
with a new paragraph in RATIONALE:
Earlier versions of this standard were silent regarding whether the
<b>-perm</b> primary takes into account the file mode creation mask
when the <i>op</i> symbols '+' and '-' are used without <b>who</b>
being specified, and required the mask to be disregarded when the
<i>op</i> symbol '=' is used without <b>who</b>. The latter resulted
in a surprising inconsistency with <i>chmod</i>, and also meant that
'=' without <b>who</b> just worked the same as '=' with a <b>who</b>
of 'a', disallowing useful functionality. Some implementations used
the mask anyway, despite the requirement not to. The standard now
requires that the way <i>find</i> handles these <i>op</i> symbols is
consistent with <i>chmod</i>. Applications that need the old behavior
can simply use '=' with a <b>who</b> of 'a' instead of without
<b>who</b>.
--
Geoff Clare <g.cl...@opengroup.org>
The Open Group, Apex Plaza, Forbury Road, Reading, RG1 1AX, England
