bug#39596: 26.3; Export INSIDE_EMACS with Eshell

bug#39596: 26.3; Export INSIDE_EMACS with Eshell

[Pierre Neidhardt]

[-- Attachment #1: Type: text/plain, Size: 350 bytes --]


Eshell does not have INSIDE_EMACS in its environment (unlike M-x shell)
which I think is a bug as it breaks the behaviour of programs that make
provisions for Emacs being used as a shell.

See
https://lists.gnu.org/archive/html/guix-devel/2020-02/msg00029.html
for a discussion.

Would it be possible to export this variable with Eshell?  Thanks!



[-- Attachment #2.1: Type: text/plain, Size: 48 bytes --]


-- 
Pierre Neidhardt
https://ambrevar.xyz/

[-- Attachment #2.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 487 bytes --]

bug#39596: 26.3; Export INSIDE_EMACS with Eshell

[Federico Tedin]

[-- Attachment #1: Type: text/plain, Size: 679 bytes --]

> Eshell does not have INSIDE_EMACS in its environment (unlike M-x shell)
> which I think is a bug as it breaks the behaviour of programs that make
> provisions for Emacs being used as a shell.
>
> See
> https://lists.gnu.org/archive/html/guix-devel/2020-02/msg00029.html
> for a discussion.
>
> Would it be possible to export this variable with Eshell?  Thanks!

I have added this feature to Eshell and created a patch, please check if
this works for you.

Additionally, I noticed that the doc string for
`eshell-variable-aliases-list' mentioned an `eshell-user-aliases-list',
variable but wasn't able to find it anywhere (neither using the Git
log), so I removed the mention.


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-Copy-INSIDE_EMACS-env-variable-to-subprocesses-in-Es.patch --]
[-- Type: text/x-patch, Size: 4158 bytes --]

From cf93960de7d3d92ccb7a5465851bbcb55a0f20d9 Mon Sep 17 00:00:00 2001
From: Federico Tedin <federicotedin@gmail.com>
Date: Wed, 19 Feb 2020 00:11:35 +0100
Subject: [PATCH] Copy INSIDE_EMACS env variable to subprocesses in Eshell

* lisp/eshell/em-dirs.el (eshell-dirs-initialize): Add INSIDE_EMACS
variable to buffer-local value of eshell-variable-aliases-alist.
* lisp/eshell/esh-var.el (eshell-variable-aliases-list): Update doc
string; remove mention of eshell-user-aliases-list and explain that
variables can optionally be copied to subprocesses' environments.
* test/lisp/eshell/eshell-tests.el (eshell-test/inside-emacs-var): Add
test for the INSIDE_EMACS variable.
* etc/NEWS: Announce changes.
---
 etc/NEWS                         |  6 ++++++
 lisp/eshell/em-dirs.el           |  3 +++
 lisp/eshell/esh-var.el           | 11 ++++++-----
 test/lisp/eshell/eshell-tests.el |  9 ++++++++-
 4 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/etc/NEWS b/etc/NEWS
index 1f8e6049a8..238184df24 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -120,6 +120,12 @@ To revert to the previous behaviour,
 unconditionally aborts the current edebug instrumentation with the
 supplied error message.
 
+** Eshell
+
+---
+*** Environment variable INSIDE_EMACS is now copied to subprocesses.
+Its value equals the result of evaluating '(format "%s,eshell" emacs-version)'.
+
 ** Tramp
 
 +++
diff --git a/lisp/eshell/em-dirs.el b/lisp/eshell/em-dirs.el
index 1949e5dc8f..b478ee028a 100644
--- a/lisp/eshell/em-dirs.el
+++ b/lisp/eshell/em-dirs.el
@@ -191,6 +191,9 @@ eshell-dirs-initialize
 		        (unless (ring-empty-p eshell-last-dir-ring)
 			  (expand-file-name
 			   (ring-ref eshell-last-dir-ring 0))))
+            t)
+           ("INSIDE_EMACS" ,(lambda (_indices)
+                              (format "%s,eshell" emacs-version))
             t))))
 
   (when eshell-cd-on-directory
diff --git a/lisp/eshell/esh-var.el b/lisp/eshell/esh-var.el
index 327a1def46..4231be92fb 100644
--- a/lisp/eshell/esh-var.el
+++ b/lisp/eshell/esh-var.el
@@ -179,10 +179,8 @@ eshell-variable-aliases-list
 	      (eshell-apply-indices eshell-command-arguments
 				    indices)))))
   "This list provides aliasing for variable references.
-It is very similar in concept to what `eshell-user-aliases-list' does
-for commands.  Each member of this defines the name of a command,
-and the Lisp value to return for that variable if it is accessed
-via the syntax `$NAME'.
+Each member of this defines the name of a command, and the Lisp value
+to return for that variable if it is accessed via the syntax `$NAME'.
 
 If the value is a function, that function will be called with two
 arguments: the list of the indices that was used in the reference, and
@@ -190,7 +188,10 @@ eshell-variable-aliases-list
 For example, a reference of `$NAME[10][20]' would result in the
 function for alias `NAME' being called (assuming it were aliased to a
 function), and the arguments passed to this function would be the list
-'(10 20)', and nil."
+'(10 20)', and nil.
+
+Additionally, each member may specify if it should be copied to the
+environment of created subprocesses."
   :type '(repeat (list string sexp
 		       (choice (const :tag "Copy to environment" t)
 			       (const :tag "Use only in Eshell" nil)))))
diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index 026818ab06..f98e4ce92b 100644
--- a/test/lisp/eshell/eshell-tests.el
+++ b/test/lisp/eshell/eshell-tests.el
@@ -167,7 +167,14 @@ eshell-test/last-arg-var
   "Test using the \"last arg\" ($_) variable"
   (with-temp-eshell
    (eshell-command-result-p "+ 1 2; + $_ 4"
-                             "3\n6\n")))
+                            "3\n6\n")))
+
+(ert-deftest eshell-test/inside-emacs-var ()
+  "Test presence of \"INSIDE_EMACS\" in subprocesses"
+  (with-temp-eshell
+   (eshell-command-result-p "env"
+                            (format "INSIDE_EMACS=%s,eshell"
+                                    emacs-version))))
 
 (ert-deftest eshell-test/escape-nonspecial ()
   "Test that \"\\c\" and \"c\" are equivalent when \"c\" is not a
-- 
2.21.1 (Apple Git-122.3)

bug#39596: 26.3; Export INSIDE_EMACS with Eshell

[Pierre Neidhardt]

[-- Attachment #1: Type: text/plain, Size: 589 bytes --]

Thanks for looking at this, Federico!

Your patch looks good to me, just one comment below:

> --- a/lisp/eshell/em-dirs.el
> +++ b/lisp/eshell/em-dirs.el
> @@ -191,6 +191,9 @@ eshell-dirs-initialize
>  		        (unless (ring-empty-p eshell-last-dir-ring)
>  			  (expand-file-name
>  			   (ring-ref eshell-last-dir-ring 0))))
> +            t)
> +           ("INSIDE_EMACS" ,(lambda (_indices)
> +                              (format "%s,eshell" emacs-version))
>              t))))

Why did you unquote the lambda here?

-- 
Pierre Neidhardt
https://ambrevar.xyz/

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 487 bytes --]

bug#39596: 26.3; Export INSIDE_EMACS with Eshell

[Federico Tedin]

Pierre Neidhardt <mail@ambrevar.xyz> writes:

> Thanks for looking at this, Federico!
>
> Your patch looks good to me, just one comment below:
>
>> --- a/lisp/eshell/em-dirs.el
>> +++ b/lisp/eshell/em-dirs.el
>> @@ -191,6 +191,9 @@ eshell-dirs-initialize
>>  		        (unless (ring-empty-p eshell-last-dir-ring)
>>  			  (expand-file-name
>>  			   (ring-ref eshell-last-dir-ring 0))))
>> +            t)
>> +           ("INSIDE_EMACS" ,(lambda (_indices)
>> +                              (format "%s,eshell" emacs-version))
>>              t))))
>
> Why did you unquote the lambda here?

I need to unquote the lambda to get its value, right? Or maybe not, and
I'm misunderstanding how lambdas work. I did notice though that the
other lambdas in the list are unquoted.

- Fede

bug#39596: 26.3; Export INSIDE_EMACS with Eshell

[Pierre Neidhardt]

[-- Attachment #1: Type: text/plain, Size: 403 bytes --]

Federico Tedin <federicotedin@gmail.com> writes:

> I need to unquote the lambda to get its value, right? Or maybe not, and
> I'm misunderstanding how lambdas work. I did notice though that the
> other lambdas in the list are unquoted.

I asked because the other lambdas are not unquoted on Emacs 26.3.
If it changed upstream, no problem then! :)

-- 
Pierre Neidhardt
https://ambrevar.xyz/

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 487 bytes --]

bug#39596: 26.3; Export INSIDE_EMACS with Eshell

[Andreas Schwab]

On Feb 19 2020, Federico Tedin wrote:

> Pierre Neidhardt <mail@ambrevar.xyz> writes:
>
>> Thanks for looking at this, Federico!
>>
>> Your patch looks good to me, just one comment below:
>>
>>> --- a/lisp/eshell/em-dirs.el
>>> +++ b/lisp/eshell/em-dirs.el
>>> @@ -191,6 +191,9 @@ eshell-dirs-initialize
>>>  		        (unless (ring-empty-p eshell-last-dir-ring)
>>>  			  (expand-file-name
>>>  			   (ring-ref eshell-last-dir-ring 0))))
>>> +            t)
>>> +           ("INSIDE_EMACS" ,(lambda (_indices)
>>> +                              (format "%s,eshell" emacs-version))
>>>              t))))
>>
>> Why did you unquote the lambda here?
>
> I need to unquote the lambda to get its value, right?

Unquoting allows it to be byte-compiled.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

bug#39596: 26.3; Export INSIDE_EMACS with Eshell

[Federico Tedin]

Andreas Schwab <schwab@suse.de> writes:

> On Feb 19 2020, Federico Tedin wrote:
>
>> Pierre Neidhardt <mail@ambrevar.xyz> writes:
>>
>>> Thanks for looking at this, Federico!
>>>
>>> Your patch looks good to me, just one comment below:
>>>
>>>> --- a/lisp/eshell/em-dirs.el
>>>> +++ b/lisp/eshell/em-dirs.el
>>>> @@ -191,6 +191,9 @@ eshell-dirs-initialize
>>>>  		        (unless (ring-empty-p eshell-last-dir-ring)
>>>>  			  (expand-file-name
>>>>  			   (ring-ref eshell-last-dir-ring 0))))
>>>> +            t)
>>>> +           ("INSIDE_EMACS" ,(lambda (_indices)
>>>> +                              (format "%s,eshell" emacs-version))
>>>>              t))))
>>>
>>> Why did you unquote the lambda here?
>>
>> I need to unquote the lambda to get its value, right?
>
> Unquoting allows it to be byte-compiled.
>
> Andreas.

Wasn't aware of that, thanks.