Re: [gentoo-dev] [PATCH 0/2] Add esed.eclass for sed that dies if caused no changes

[Anna V]

On 2022-06-03 00:45, Ionen Wolkens wrote:
> On Fri, Jun 03, 2022 at 06:09:38AM +0200, Michał Górny wrote:
> > On Tue, 2022-05-31 at 07:23 -0400, Ionen Wolkens wrote:
> > > Often preferable to use patches so this happens, but sed have its
> > > uses/convenience and this intend to help reduce the amount of old
> > > broken seds causing issues that go unnoticed on bumps.
> > >
> > > Inspired by app-portage/iwdevtools' qa-sed (warns on any seds), but
> > > this is for more deterministic use in ebuilds.
> > >
> > > Also slightly shortens sed use, -i is default, and no need to || die.
> > > (see @EXAMPLE in eclass for a quick usage overview).
> > >
> >
> > To be honest, I strongly dislike this.  It really feels like trying to
> > make an adapter for a square wheel, while the right solution would be to
> > replace the wheel.  On top of that, ton of evals which are pretty much
> > a huge "no-no".
>
> About evals, the two eval is just to silence this:
>
>     var=$(printf "\0")
 
Or in ksh93 syntax:

var=$'\0'

> The 2>/dev/null doesn't work without wrapping it, aka
>
>     eval 'var=$(printf "\0")' 2>/dev/null
>
> No variables are expanded pre-eval so it's just evaluating a
> static statement. eval can be removed, but it'll be noisy
> if someone happens to sed binary files.
>
> >
> > Perhaps it would be better to forget about trying to work miracles with
> > sed and instead write a trivial shell replacement for the most common
> > use cases.  One thing I'd love to see is a simple substitution command
> > that would work for paths/CFLAGS on RHS without having to worry about
> > them conflicting with the pattern delimiter.
> >
> > --
> > Best regards,
> > Michał Górny
> >
> >
>
> --
> ionen