bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[Tino Calancha]

X-Debbugs-CC: John Wiegley <jwiegley@gmail.com>

emacs -r -Q -l em-ls -l esh-cmd -eval "(customize-set-variable 'eshell-ls-use-in-dired t)"

M-: (dired source-directory "-lg") RET
;; Signal eshell-interactive-output-p: (wrong-type-argument arrayp nil)

It fails because eshell-current-handles is nil.
Even if this variable is set, then (throw 'eshell-external ...
in `eshell--do-opts' won't be catched.

The following works:
M-x eshell RET
ls -lg (eval source-directory) RET


In GNU Emacs 25.2.50.3 (x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
 of 2017-08-03 built on calancha-pc
Windowing system distributor 'The X.Org Foundation', version 11.0.11902000
System Description:	Debian GNU/Linux 9.1 (stretch)

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[John Wiegley]

>>>>> "TC" == Tino Calancha <tino.calancha@gmail.com> writes:

TC> M-: (dired source-directory "-lg") RET
TC> ;; Signal eshell-interactive-output-p: (wrong-type-argument arrayp nil)

Why would eshell be involving with using dired at all?  Do you have a
customization present that is causing this?

-- 
John Wiegley                  GPG fingerprint = 4710 CF98 AF9B 327B B80F
http://newartisans.com                          60E1 46C4 BD1A 7AC1 4BA2

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[Tino Calancha]

On Wed, 2 Aug 2017, John Wiegley wrote:

>>>>>> "TC" == Tino Calancha <tino.calancha@gmail.com> writes:
>
> TC> M-: (dired source-directory "-lg") RET
> TC> ;; Signal eshell-interactive-output-p: (wrong-type-argument arrayp nil)
>
> Why would eshell be involving with using dired at all?  Do you have a
> customization present that is causing this?
Not me.  I am just testing all the functionality available.
Someone added in 2000 a defcustom `eshell-ls-use-in-dired', so 
that you can run eshell-ls to list directories with Dired.

Now i understand why i get this error: the dired support was added
'a posteriori'.

I think an user who want to set `eshell-ls-use-in-dired' non-nil is
likely someone with no external 'ls' installed.

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[John Wiegley]

>>>>> Tino Calancha <calancha@gmail.com> writes:

> Now i understand why i get this error: the dired support was added 'a
> posteriori'.

> I think an user who want to set `eshell-ls-use-in-dired' non-nil is likely
> someone with no external 'ls' installed.

I added eshell-ls-use-in-dired long ago, to support a Windows machine I was
working on.  At least the bug report now makes much more sense, thank you.

-- 
John Wiegley                  GPG fingerprint = 4710 CF98 AF9B 327B B80F
http://newartisans.com                          60E1 46C4 BD1A 7AC1 4BA2

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[Glenn Morris]

John Wiegley wrote:

>> I think an user who want to set `eshell-ls-use-in-dired' non-nil is likely
>> someone with no external 'ls' installed.
>
> I added eshell-ls-use-in-dired long ago, to support a Windows machine I was
> working on.  At least the bug report now makes much more sense, thank you.

Why is it desirable to use eshell ls with dired instead of ls-lisp?
Maybe it would be better to remove it rather than fix it.
(It usually goes well when I suggest this...)

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[John Wiegley]

>>>>> Glenn Morris <rgm@gnu.org> writes:

> Why is it desirable to use eshell ls with dired instead of ls-lisp? Maybe it
> would be better to remove it rather than fix it. (It usually goes well when
> I suggest this...)

I like it more than ls-lisp, and it pays attention to all the same options you
can use to configure eshell/ls at the Eshell command-line.  If anything, why
not get rid of ls-lisp?

-- 
John Wiegley                  GPG fingerprint = 4710 CF98 AF9B 327B B80F
http://newartisans.com                          60E1 46C4 BD1A 7AC1 4BA2

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[Eli Zaretskii]

> From: John Wiegley <jwiegley@gmail.com>
> Date: Thu, 03 Aug 2017 14:46:14 -0700
> Cc: Tino Calancha <calancha@gmail.com>, 27919@debbugs.gnu.org,
> 	Tino Calancha <tino.calancha@gmail.com>
> 
> If anything, why not get rid of ls-lisp?

Because (a) it's much smaller than Eshell, so better suited for
something that's preloaded; and (b) it supports quite a few options
that Eshell doesn't, AFAIK, and which Windows users might expect to be
available, as they are available in "other file-system browsers".

I actually think that getting rid of any of these two is not a good
idea, but that's me.

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[John Wiegley]

>>>>> Eli Zaretskii <eliz@gnu.org> writes:

> Because (a) it's much smaller than Eshell, so better suited for something
> that's preloaded; and (b) it supports quite a few options that Eshell
> doesn't, AFAIK, and which Windows users might expect to be available, as
> they are available in "other file-system browsers".

I wonder then how hard it would be to adapt Eshell to use ls-lisp.  Does
ls-lisp provide more than just dired-suited output?  eshell/ls tries hard to
be pretty at the shell prompt too.

-- 
John Wiegley                  GPG fingerprint = 4710 CF98 AF9B 327B B80F
http://newartisans.com                          60E1 46C4 BD1A 7AC1 4BA2

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[Eli Zaretskii]

> From: John Wiegley <jwiegley@gmail.com>
> Cc: rgm@gnu.org,  calancha@gmail.com,  27919@debbugs.gnu.org,  tino.calancha@gmail.com
> Date: Fri, 04 Aug 2017 10:05:07 -0700
> 
> Does ls-lisp provide more than just dired-suited output?

Not really.  But it has options like ls-lisp-dirs-first,
ls-lisp-ignore-case, ls-lisp-format-time-list, and
ls-lisp-use-localized-time-format.

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[Drew Adams]

> > Does ls-lisp provide more than just dired-suited output?
> 
> Not really.  But it has options like ls-lisp-dirs-first,
> ls-lisp-ignore-case, ls-lisp-format-time-list, and
> ls-lisp-use-localized-time-format.

And such options are also supported by libraries such as
`dired-sort-menu.el' (also by Francis J. Wright).

https://www.emacswiki.org/emacs/DiredSortMenu

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[Tino Calancha]

On Thu, 3 Aug 2017, John Wiegley wrote:

>>>>>> Glenn Morris <rgm@gnu.org> writes:
>
>> Why is it desirable to use eshell ls with dired instead of ls-lisp? Maybe it
>> would be better to remove it rather than fix it. (It usually goes well when
>> I suggest this...)
>
> I like it more than ls-lisp, and it pays attention to all the same options you
> can use to configure eshell/ls at the Eshell command-line.  If anything, why
> not get rid of ls-lisp?
I think 'The battle of emulated ls with elisp' is about to start.  I read
about in a Tolkien book; don't remember who won, though.

bug#27919: 25.2.50; dired + eshell-ls: fallback to external ls fails

[Lars Ingebrigtsen]

Tino Calancha <tino.calancha@gmail.com> writes:

> emacs -r -Q -l em-ls -l esh-cmd -eval "(customize-set-variable 'eshell-ls-use-in-dired t)"
>
> M-: (dired source-directory "-lg") RET
> ;; Signal eshell-interactive-output-p: (wrong-type-argument arrayp nil)
>
> It fails because eshell-current-handles is nil.
> Even if this variable is set, then (throw 'eshell-external ...
> in `eshell--do-opts' won't be catched.

This bug is still present in Emacs 29.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no