[debbugs-tracker] bug#23779: closed (25.0.95; consing "SHELLVAR" onto process-environment doesn't remove it from subprocess env)

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Your message dated Mon, 20 Jun 2016 17:21:03 +0300
with message-id <address@hidden>
and subject line Re: bug#23779: 25.0.95; consing "SHELLVAR" onto 
process-environment doesn't remove it from subprocess env
has caused the debbugs.gnu.org bug report #23779,
regarding 25.0.95; consing "SHELLVAR" onto process-environment doesn't remove 
it from subprocess env
to be marked as done.

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23779: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=23779
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> Subject: 
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> 25.0.95; consing "SHELLVAR" onto process-environment doesn't remove it from subprocess env
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> Date: 
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> Thu, 16 Jun 2016 23:33:02 -0400
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> Start emacs -Q, evaluate the following lisp code (I wrote the return
> values after ;=>)
>
> (defun check-env-var (var)
>   (catch 'ret
>     (dolist (var=val (process-lines "env"))
>       (when (string-prefix-p var var=val)
>         (throw 'ret var=val)))))
>
> (check-env-var "SHELL");=>"SHELL=/bin/bash"
> (let ((process-environment (copy-sequence process-environment)))
>   (setenv "SHELL" nil)
>   (check-env-var "SHELL"));=>nil
> (let ((process-environment (cons "SHELL" process-environment)))
>   (check-env-var "SHELL"));=>"SHELL=/bin/bash"
> (let ((process-environment (cons "SHELL=" process-environment)))
>   (check-env-var "SHELL"));=>"SHELL="
>
> As you can see from the 3rd expression, contrary to its docstring,
> consing the env variable "SHELL" onto process-environment has no
> effect at all.
>
> process-environment is a variable defined in ‘C source code’.
> Its value is
> [...]
> Documentation:
> List of overridden environment variables for subprocesses to inherit.
> Each element should be a string of the form ENVVARNAME=VALUE.
>
> Entries in this list take precedence to those in the frame-local
> environments.  Therefore, let-binding ‘process-environment’ is an easy
> way to temporarily change the value of an environment variable,
> irrespective of where it comes from.  To use ‘process-environment’ to
> remove an environment variable, include only its name in the list,
> without "=VALUE".
>
>
>
> --- End Message ---
> --- Begin Message ---
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> Subject: 
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> Re: bug#23779: 25.0.95; consing "SHELLVAR" onto process-environment doesn't remove it from subprocess env
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> Date: 
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> Mon, 20 Jun 2016 17:21:03 +0300
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> > Cc: address@hidden, address@hidden, address@hidden,
> >  address@hidden
> > From: Paul Eggert <address@hidden>
> > Date: Mon, 20 Jun 2016 00:53:21 +0200
> > 
> > On 06/19/2016 05:01 PM, Eli Zaretskii wrote:
> > >> >I resisted the temptation of cleaning up the surrounding code to
> > >> >make it more readable.
> > > Feel free to do that on master; I can mark the emacs-25 fix "not to be
> > > merged".
> > 
> > Please don't bother.
>
> OK, thanks.  Pushed as 5f37572 on the emacs-25 branch, and closing.
>
>
> --- End Message ---