From: Filipe Silva <filipe.silva@gmail.com>
To: Oliver Kiddle <okiddle@yahoo.co.uk>
Cc: zsh-users@zsh.org
Subject: Re: Next release (5.3)
Date: Tue, 12 Jul 2016 23:56:39 -0300 [thread overview]
Message-ID: <CAEwkUWMuAkq2e650tuZymX_wVaM51Ra7JNPccKbpFwCOFyZAFw@mail.gmail.com> (raw)
In-Reply-To: <37271.1468354988@hydra.kiddle.eu>
[-- Attachment #1: Type: text/plain, Size: 2381 bytes --]
Wait good people. Maybe I am missing something, but why the specific focus
on the non-posix `realpath`? Doesn't `readlink -f` emulates what realpath
does but it is always available because it is posix? Maybe :A should really
call `readlink -f`? Makes sense?
On Tue, Jul 12, 2016 at 5:23 PM, Oliver Kiddle <okiddle@yahoo.co.uk> wrote:
> Bart wrote:
>
> Thanks for the concise summary.
>
> > The present situation is:
> >
> > 1. :a performs a string-manipulation on the path to remove any
> > relative path segments.
> > 2. :A does (1) and then calls realpath on the result.
>
> The only advantage I can think of that is that it might do what you want
> in the case where you don't have read permissions on one of the
> intermediate directories. Otherwise, the potential for the result being
> a different file is not good.
>
> > This matches the documentation.
> >
> > Daniel is arguing that (1) is essentially useless and calling realpath
> > after that may give a different result than realpath on the original
> > path string. His suggestion is:
> >
> > 1. :a is as before
> > 2. :A calls realpath, and does (1) only if there is no realpath
>
> That seems like a good approach. It might also try (1) if realpath fails.
>
> I don't have many uses in scripts to check but I'd expect it'd be
> more likely to fix scripts than introduce a bug.
>
> With that approach, I guess you could get the original :A behaviour by
> chaining the modifiers - :a:A
>
> And adding modifiers just makes it harder to work out which one you
> want. I could see a use for a pure readlink one, however.
>
> > (It's unclear to me whether there would be any reason to do (1) AFTER
> > calling realpath.)
> >
> > The emerging consensus seems to be for:
> >
> > 1. :a is as before
> > 2. :A is as before
> > 3. new modifier calls realpath and does (1) if no realpath
> >
> > Is there one of those three cases with which you agree, or are you in
> > fact asking for zsh to re-implement realpath internally?
>
> If systems lacking realpath were common, it would be worth doing
> but from a check of online man pages it seems to be there on currently
> relevant systems. Our own implementation might handle unreadable
> directories followed by ../ but there might be some OS specific
> oddities: case-insensitivity on macOS and Solaris xattrs come to
> mind.
>
> Oliver
>
next prev parent reply other threads:[~2016-07-13 2:56 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-05 4:57 realpath(3), symlinks, '..' components, and the ':A' word modifier Daniel Shahaf
2016-07-05 12:54 ` Roland Eggner
2016-07-05 13:24 ` Vadim Zeitlin
2016-07-06 15:15 ` Filipe
[not found] ` <20160705125430.GA29959__3886.85245202414$1467723835$gmane$org@mobil.systemanalysen.net>
2016-07-07 2:00 ` Daniel Shahaf
2016-07-07 17:20 ` Bart Schaefer
[not found] ` <20160705093321.79d7c4bc@pwslap01u.europe.root.pri>
2016-07-12 7:58 ` Next release (5.3) Roman Neuhauser
2016-07-12 16:40 ` Bart Schaefer
2016-07-12 20:23 ` Oliver Kiddle
2016-07-13 2:56 ` Filipe Silva [this message]
2016-07-13 4:45 ` Bart Schaefer
2016-07-13 5:09 ` Filipe Silva
2016-07-13 9:32 ` Peter Stephenson
2016-07-13 9:59 ` Peter Stephenson
2016-07-13 16:35 ` Bart Schaefer
2016-07-13 16:59 ` Peter Stephenson
2016-07-13 17:50 ` Bart Schaefer
[not found] ` <20160713105910.2b33701c__17004.846657119$1468404086$gmane$org@pwslap01u.europe.root.pri>
2016-07-17 14:59 ` Daniel Shahaf
[not found] ` <20160713103233.14bfd05a__26126.9551389434$1468402471$gmane$org@pwslap01u.europe.root.pri>
2016-07-17 14:59 ` [PATCH] improve :A docs (was: Re: Next release (5.3)) Daniel Shahaf
[not found] ` <20160717145931.GA4859__10178.6871244714$1468767679$gmane$org@tarsus.local2>
2016-07-20 6:54 ` Daniel Shahaf
2016-07-13 7:41 ` Next release (5.3) Roman Neuhauser
2016-07-13 17:36 ` Bart Schaefer
2016-07-20 13:05 ` Vincent Lefevre
2016-07-20 14:00 ` Vincent Lefevre
2016-07-20 14:15 ` Peter Stephenson
2016-07-20 14:19 ` Peter Stephenson
[not found] ` <20160720151517.6a833f2c__37436.2382958227$1469024822$gmane$org@pwslap01u.europe.root.pri>
2016-07-21 5:40 ` Daniel Shahaf
2016-07-21 9:19 ` Peter Stephenson
2016-07-21 3:50 ` Bart Schaefer
[not found] ` <160712094017.ZM17395__33553.1437922784$1468341719$gmane$org@torch.brasslantern.com>
2016-07-13 5:00 ` Daniel Shahaf
[not found] ` <20160712075849.GG1537__20664.8654224866$1468310440$gmane$org@isis.sigpipe.cz>
2016-07-13 5:01 ` Daniel Shahaf
2016-07-20 12:44 ` realpath(3), symlinks, '..' components, and the ':A' word modifier Vincent Lefevre
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