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From: Adam Thornton <athornton@gmail.com>
To: "Michael Kjörling" <michael@kjorling.se>,
	"The Eunuchs Hysterical Society" <tuhs@tuhs.org>
Subject: Re: [TUHS] moving directories in svr2
Date: Fri, 31 Dec 2021 08:53:38 -0700	[thread overview]
Message-ID: <CAP2nic3RWX=nS53xTF4096qFTYKB=y35hVGOXcoEforexZbG6w@mail.gmail.com> (raw)
In-Reply-To: <97f563fa-5a17-424b-acc6-07cf127f496d@localhost>

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Slightly older, but also slightly more fundamental to the system, you need
look no farther than Solaris's `/bin/sh` for an illustrated example of the
pros and cons of maintaining backwards compatibility.  It was a pain by,
say, 2007, to have to check if you were running on SunOS and use
`/usr/xpg4/bin/sh` (IIRC) if you wanted a POSIX shell--by that point the
other major vendors (and Linux) had something POSIX as the default shell.
But Sun had an installed user base with a bunch of shell scripts that
depended on pre-POSIX semantics.

Of course, people don't do a particularly good job of writing POSIX shell
either.  Just this past week one of our refactoring projects at the Rubin
Observatory had some difficulty because Debian uses dash as its
non-interactive POSIX shell.  Some bit of some conda package that we need
claimed to work with dash (and POSIX generally) but in reality didn't.  But
it always worked fine on bash and zsh, so no one had gotten bitten until we
did.

Adam

On Fri, Dec 31, 2021 at 6:40 AM Michael Kjörling <michael@kjorling.se>
wrote:

> On 31 Dec 2021 16:55 +1100, from robpike@gmail.com (Rob Pike):
> > And of course you're right, but we've known how to roll out breaking
> > changes in software for a very long time now. And we do so often. Few
> Unix
> > programs from the past would compile and run today without being updated
> to
> > "modern" interfaces and compilers.
> >
> > I believe it could be done, and I believe it should be done. Rolled out
> > carefully and explained well it would please far more than it offends,
> and
> > is arguably far closer to correct than the current situation.
>
> Seems to me that we have a decent, relatively current case study of
> this with Python 2 vs Python 3.
>
> Which is probably a good bit easier actually, because maintaining the
> ability to run Python 2 applications while introducing the ability to
> run Python 3 applications is likely easier than introducing changes to
> how something as relatively fundamental as how ".." behaves in paths
> while at the same time maintaining backwards compatibility with the
> old behavior, where different users and different applications on the
> same system might very well expect different behavior...
>
> --
> Michael Kjörling • https://michael.kjorling.se • michael@kjorling.se
>  “Remember when, on the Internet, nobody cared that you were a dog?”
>
>

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  reply	other threads:[~2021-12-31 15:54 UTC|newest]

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-30  3:45 Noel Chiappa
2021-12-30  4:02 ` Bakul Shah
2021-12-30 16:40 ` Theodore Ts'o
2021-12-30 22:31   ` Dan Cross
2021-12-31  0:43     ` Bakul Shah
2021-12-31  1:00       ` Rob Pike
2021-12-31  1:45         ` Bakul Shah
2021-12-31  2:23           ` Adam Thornton
2021-12-31 18:56       ` Chet Ramey
2021-12-31  3:08     ` Theodore Ts'o
2021-12-31  3:23       ` Rob Pike
2021-12-31  5:16         ` Theodore Ts'o
2021-12-31  5:21           ` Dan Cross
2021-12-31  5:55           ` Rob Pike
2021-12-31 13:32             ` Michael Kjörling
2021-12-31 15:53               ` Adam Thornton [this message]
2021-12-31 16:13                 ` Arthur Krewat
2021-12-31 18:17                 ` Dan Cross
2021-12-31 18:23                   ` Larry McVoy
2021-12-31 18:37                     ` Dan Cross
2021-12-31 18:29                   ` Arthur Krewat
2022-01-01  0:09                   ` Theodore Ts'o
2022-01-03 13:35                     ` Dan Cross
2022-01-03 20:23                       ` Theodore Ts'o
2022-01-03 20:45                         ` Warner Losh
2022-01-03 21:15                         ` Dan Cross
2022-01-03 22:26                           ` Theodore Ts'o
2022-01-03 23:10                             ` Dan Cross
2022-01-04 15:45                             ` Chet Ramey
2022-01-09 19:28                             ` Larry McVoy
2022-01-03 23:21                           ` Doug McIntyre
2022-01-03 23:37                             ` Adam Thornton
2022-01-04 14:49                               ` Stuart Remphrey
2022-01-03 23:44                             ` Larry McVoy
2022-01-03 23:56                               ` [TUHS] SMP: BSD vs System V (once was: moving directories in svr2) Greg 'groggy' Lehey
2022-01-07 19:01                                 ` Warner Losh
2022-01-09 17:31                                 ` Stuart Remphrey
2022-01-13  2:35                                 ` Kevin Bowling
2022-01-03 23:56                               ` [TUHS] moving directories in svr2 Warner Losh
2022-01-04  2:28                               ` Theodore Ts'o
2022-01-04  2:42                                 ` Larry McVoy
2022-01-04  9:28                                 ` [TUHS] Mythical Distress Sale (was Re: moving directories in svr2) Rob Gingell
2022-01-04 15:17                                   ` Larry McVoy
2022-01-04 15:26                                     ` arnold
2022-01-04 15:40                                       ` Larry McVoy
2022-01-04 15:48                                         ` Richard Salz
2022-01-03 22:57                         ` [TUHS] moving directories in svr2 Phil Budne
2022-01-04 15:40                         ` [TUHS] VRFs (was Re: moving directories in svr2) Derek Fawcus
2021-12-31  5:12       ` [TUHS] moving directories in svr2 Bakul Shah
  -- strict thread matches above, loose matches on Subject: below --
2021-12-29 19:33 Noel Chiappa
2021-12-30  3:40 ` Jay Logue via TUHS
2021-12-29 19:13 Douglas McIlroy
2021-12-29 19:37 ` Dan Cross
2021-12-29 20:15   ` Dan Cross
2021-12-29 20:42     ` Richard Salz
2021-12-29 20:58       ` Dan Cross
2021-12-29 21:20         ` Clem Cole
2021-12-30  3:15       ` Bakul Shah
2021-12-29 17:12 Douglas McIlroy
2021-12-29 16:59 Bakul Shah
2021-12-29 17:04 ` Clem Cole
2021-12-29 17:14 ` arnold
2021-12-29 17:38   ` Clem Cole
2021-12-29 17:49     ` Brantley Coile
2021-12-29 18:27       ` ron minnich
2021-12-29 20:59         ` Rob Pike
2021-12-29 14:33 Will Senn
2021-12-29 15:02 ` arnold
2021-12-29 15:38   ` Will Senn
2021-12-29 15:44     ` Richard Salz
2021-12-29 16:17       ` Clem Cole
2021-12-29 16:58         ` Richard Salz
2021-12-30  5:14         ` Dan Stromberg
2021-12-30 16:22           ` Clem Cole
2021-12-30 18:02           ` John Cowan
2021-12-30 23:04             ` Richard Salz
2021-12-29 15:17 ` Clem Cole
2021-12-29 15:44   ` Will Senn
2021-12-29 16:10     ` Clem Cole
2021-12-29 16:33       ` Warner Losh
2021-12-29 16:01   ` Bakul Shah

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