From: Noam Postavsky <npostavs@users.sourceforge.net>
To: 23779@debbugs.gnu.org
Subject: bug#23779: 25.0.95; consing "SHELLVAR" onto process-environment doesn't remove it from subprocess env
Date: Thu, 16 Jun 2016 23:33:02 -0400 [thread overview]
Message-ID: <CAM-tV-_EBfqQPE0taL7=EyxV3Z_tvzBsu+3FKeYtpQSqvTj7Vw@mail.gmail.com> (raw)
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".
next reply other threads:[~2016-06-17 3:33 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-17 3:33 Noam Postavsky [this message]
2016-06-17 7:11 ` bug#23779: 25.0.95; consing "SHELLVAR" onto process-environment doesn't remove it from subprocess env Eli Zaretskii
2016-06-17 12:17 ` Dmitry Gutov
2016-06-17 14:01 ` Eli Zaretskii
2016-06-17 14:12 ` Dmitry Gutov
2016-06-17 14:19 ` Eli Zaretskii
2016-06-17 14:47 ` Dmitry Gutov
2016-06-17 16:52 ` Andreas Schwab
2016-06-17 16:55 ` Dmitry Gutov
2016-06-17 17:06 ` Eli Zaretskii
2016-06-17 19:01 ` Dmitry Gutov
2016-06-17 20:10 ` Eli Zaretskii
2016-06-17 21:26 ` Dmitry Gutov
2016-06-18 7:51 ` Eli Zaretskii
2016-06-18 1:36 ` Noam Postavsky
2016-06-18 1:44 ` Dmitry Gutov
2016-06-19 2:27 ` Paul Eggert
2016-06-19 15:01 ` Eli Zaretskii
2016-06-19 22:53 ` Paul Eggert
2016-06-20 14:21 ` Eli Zaretskii
2016-06-21 13:53 ` Dmitry Gutov
2016-06-21 15:21 ` Eli Zaretskii
2016-06-21 15:24 ` Dmitry Gutov
2016-06-21 16:12 ` Eli Zaretskii
2016-06-21 23:05 ` Dmitry Gutov
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