Re: [PATCH 3/4] Fit to Plan 9's ANSI/POSIX compatibility layer
- From
Kyohei Kadota <lufia@lufia.org>
- Date
- Aug 10, 2020, 10:53 UTC
- Message-ID
- <CAFMepckAe9r1O8xrQemytHoZKeyLSjEpfdH=yP=+SzKPoCOf8w@mail.gmail.com>
- In-Reply-To
- <xmqq5z9vlk5q.fsf@gitster.c.googlers.com>
Show 39 quoted lines
>
> "brian m. carlson" <sandals@crustytoothpaste.net> writes:
>
> > I will note that usually the project prefers to have a human's personal
> > name here and in the commit metadata instead of a username. Junio may
> > chime in here with an opinion.
>
> Thanks, I just did.
>
> >> command_list () {
> >> - eval "grep -ve '^#' $exclude_programs" <"$1"
> >> + eval "grep -v -e '^#' $exclude_programs" <"$1"
> >
> > Is it really the case that Plan 9's grep cannot deal with bundled short
> > options? That seems to be a significant departure from POSIX and Unix
> > behavior. Regardless, this should be explained in the commit message.
>
> I am not interested in this ball of wax, but there are some pieces
> that are worth salvaging. This is one of those good bits.
>
> diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
> index 9db2f4feab..a7cc01caf9 100755
> --- a/GIT-VERSION-GEN
> +++ b/GIT-VERSION-GEN
> @@ -26,7 +26,7 @@ else
> VN="$DEF_VER"
> fi
>
> -VN=$(expr "$VN" : v*'\(.*\)')
> +VN=${VN#v}
>
> if test -r $GVF
> then
>
> BUT.
>
> Dealing with "grep" that cannot take "-ve" and forces developers to
> spell it as "-v -e" is not one of them. So is forbidding use of
> "cut".I see. I will rewrite Plan 9's ape/grep to handle bundled options well.
Show 10 quoted lines
> >> get_categories () {
> >> - tr ' ' '\n'|
> >> + tr ' ' '\012'|
> >
> > Okay, I guess. Is this something we need to handle elsewhere as well?
> > The commit message should tell us why this is necessary, and what Plan 9
> > does and doesn't support.
>
> Yeah, POSIX does want you to understand '\n' and others, but this is
> within reason for portability that I think we could swallow.I'm happy, thanks.
Show 33 quoted lines
> >> +if test -z "$(echo -n)"
> >> +then
> >> + alias print='echo -n'
> >> +else
> >> + alias print='printf %s'
> >> +fi
> >
> > Let's avoid an alias here (especially with a common builtin name) and
> > instead use a shell function. Maybe like this (not tab-indented):
> >
> > print_nonl () {
> > if command -v printf >/dev/null 2>&1
> > then
> > printf "%s" "$@"
> > else
> > echo -n "$@"
> > fi
> > }
>
> I'd rather not to see this done; "echo -n" and "echo '...\c'" are
> not portable and we do want people to use 'printf'. This directly
> goes against it.
>
> > This is also going to need some patching in the testsuite, since we use
> > printf extensively (more than 1300 times). I do hope you have perl
> > available.
>
> Eh, so what would Plan9 people do with Perl? Write a single-liner
> 'printf' script and put it in a directory on their $PATH?
>
> I am not sure if it is worth crippling the toolset our developers
> are allowed to choose from and use in our scripts and tests like
> this patch tries to do.Like other topics, I decide to implement printf(1). These new POSIX tools will be installed to Plan 9 systems from other repo or patches before building git.
Show 11 quoted lines
> If this were Windows, it might have been a different story, but what > we are talking about is Plan 9, which had the last "fourth edition" > in 2002, right? During the 18 years since then, none of its users > and developers work on porting many OSS packages, whose primary user > base are on POSIXy systems, to it and we need to apply patches like > these to each and every OSS packages of interest? I would have > expected that any exotic-minority-but-thriving-platform would be > able to tell its users "here are ports of POSIXy programs---install > them and it can become usable by those who only know Linux"? > > So, I dunno.
Final official distribution from Bell labs was released in Jan 2015. Now, There are some distributions that forked from official Plan 9 and are maintained by that community, such as 9legacy, 9front or others.
I will try to implement POSIX toolsets if it is needed because POSIX is a large spec. Thanks for your advice.