zsh-workers
 help / color / mirror / code / Atom feed
From: "Lawrence Velázquez" <larryv@zsh.org>
To: Marlon Richert <marlon.richert@gmail.com>
Cc: Bart Schaefer <schaefer@brasslantern.com>,
	Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: [PATCH] Increase $COLUMNS when generating long option completions
Date: Wed, 4 Aug 2021 03:19:41 -0400	[thread overview]
Message-ID: <CB6936F6-1D97-4CE0-ACE2-71785A163450@zsh.org> (raw)
In-Reply-To: <CAHLkEDsYUVFXEyzUG2m1O7PeXPM0J4VnscL-yM-fv2Kbj3h85A@mail.gmail.com>

> On Aug 4, 2021, at 2:53 AM, Marlon Richert <marlon.richert@gmail.com> wrote:
> On Wed, Aug 4, 2021 at 4:12 AM Lawrence Velázquez <larryv@zsh.org> wrote:
>> 
>> On Tue, Aug 3, 2021, at 10:05 AM, Marlon Richert wrote:
>>> On Mon, Aug 2, 2021 at 2:07 AM Bart Schaefer <schaefer@brasslantern.com> wrote:
>>>> I'm puzzled, doesn't this imply that the value of $COLUMNS is
>>>> incorrect on entry to the function?
>>> No, the problem results from _call_program being connected to a pipe:
>>>   _call_program $lflag options ${~words[1]} --help 2>&1 |
>>>     while IFS= read -r opt; do
>>> When ${~words[1]} is an external command, it will then not see
>>> $COLUMNS, unless $COLUMNS has been exported.
>> 
>> Isn't that the case in general?  External commands *never* see
>> COLUMNS if it isn't in the environment.  The pipe is a red herring.
>> 
>>> For example, compare the output of the following:
>>> % pip3 --help
>>> % _call_program tst pip3 --help
>>> % _call_program tst pip3 --help | cat
>>> % print -r -- "$( pip3 --help )"
>> 
>> Seems like pip is behaving differently depending on whether it's
>> outputting to a tty or not.
> 
> I feel that cannot be the whole story, because if I do any of the
> following, I get terminal-width output, instead of 80 columns:
> 
> % COLUMNS=$COLUMNS pip3 --help | cat
> % print -r -- "$( COLUMNS=$COLUMNS pip3 --help )"

Yes, these commands are explicitly setting COLUMNS in pip’s environment. As Bart said, the tty vs. not-tty distinction probably only matters when COLUMNS is not in pip’s environment.

> % _call_program tst COLUMNS=$COLUMNS pip3 --help | cat
> 
> And pip isn't the only command that works that way. For example:
> 
> % ls -x /
> Applications Library System Users Volumes bin cores dev etc home
> opt private sbin tmp usr var
> % ls -x / | cat
> Applications Library System Users Volumes
> bin cores dev etc home
> opt private sbin tmp usr
> var
> % COLUMNS=$COLUMNS ls -x / | cat
> Applications Library System Users Volumes bin cores dev etc home
> opt private sbin tmp usr var
> %

Same thing here. You are explicitly setting COLUMNS in the environment of ls, and ls is respecting it.

-- 
vq
Sent from my iPhone


  reply	other threads:[~2021-08-04  7:20 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-01 19:24 Marlon Richert
2021-08-01 23:06 ` Bart Schaefer
2021-08-03 14:05   ` Marlon Richert
2021-08-04  1:12     ` Lawrence Velázquez
2021-08-04  3:48       ` Bart Schaefer
2021-08-04  6:51       ` Marlon Richert
2021-08-04  7:19         ` Lawrence Velázquez [this message]
2021-08-05  6:19           ` Marlon Richert
2021-08-05  6:24             ` Bart Schaefer
2021-08-05 18:11               ` Marlon Richert
2021-08-05 23:44                 ` Bart Schaefer
2021-08-07 19:55                   ` Marlon Richert
2021-08-07 22:41                     ` Bart Schaefer
2021-08-10 19:04                       ` Marlon Richert
2021-08-10 19:17                         ` Marlon Richert

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CB6936F6-1D97-4CE0-ACE2-71785A163450@zsh.org \
    --to=larryv@zsh.org \
    --cc=marlon.richert@gmail.com \
    --cc=schaefer@brasslantern.com \
    --cc=zsh-workers@zsh.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://git.vuxu.org/mirror/zsh/

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).