Environment variables in Emacs can be set buffer-locally, like many
Emacs preferences, which allows users to have different buffer-local
paths for executables in different projects, specified by a
.dir-locals.el file or via a direnv integration like
envrc.
However, there's a fairly common pitfall when Emacs libraries run background processes on behalf of a user: many such libraries run processes in temporary buffers that do not inherit the calling buffer's environment. This can result in executables not being found, or the wrong versions of executables being picked up.
An example is the Emacs built-in command
shell-command-to-string. Whatever buffer-local process-environment
(or exec-path) the user has set, that command will always use the
Emacs-wide default. This is specified behaviour, but not expected
or helpful.
inheritenv provides a couple of tools for dealing with this
issue:
- Library authors can wrap code that plans to execute processes in
temporary buffers with the
inheritenvmacro. - Users can modify commands like
shell-command-to-stringusing theinheritenv-add-advicemacro.
Ensure inheritenv.el is in a directory on your load-path, and add
the following to your ~/.emacs or ~/.emacs.d/init.el:
(require 'inheritenv)If you're an Emacs 24 user or you have a recent version of
package.el you can install inheritenv from the
MELPA repository. The version of
inheritenv there will always be up-to-date.
Author: Steve Purcell
Homepage: https://github.com/purcell/inheritenv