Tags: patch


Options such as python-shell-exec-path and
python-shell-process-environment may not be applied for remote Python
shell:

(1) create a python virtual environment on the remote host:

$ python3 -m venv /tmp/test_venv

(2) emacs -Q and then eval the following code:

  --8<---------------cut here---------------start------------->8---
    (require 'python)
    (require 'tramp)

    (setq remote-dir "/ssh:<remote>:~/")

    ;; use the remote virtual environment by setting
    ;; python-shell-exec-path, python-shell-remote-exec-path, or
    ;; python-shell-virtualenv-root
    (setq python-shell-exec-path (list "/tmp/test_venv/bin"))

    ;; set environment variables for remote Python process
    (setq python-shell-process-environment '("FOO=1"))

    ;; python-shell-process-environment is not applied remotely when
    ;; connection-local tramp-remote-process-environment is used
    (connection-local-set-profile-variables
     'test
     `((tramp-remote-process-environment
        . ,(append
            '("BAR=bar")
            tramp-remote-process-environment))))
    (connection-local-set-profiles
     `(:application tramp :machine ,(file-remote-p remote-dir 'host))
     'test)

    (find-file remote-dir)
  --8<---------------cut here---------------end--------------->8---

(3) M-x run-python

(4) type 'import sys; sys.executable' in the remote python shell

The expected output is '/tmp/test_venv/bin/python', but the actual
output is '/bin/python'.

In emacs 30 and earlier version, the result is correct, with a side
effect that the remote path is changed globally, i.e. (exec-path) in
other remote buffers also contains "/tmp/test_venv/bin".

(5) type 'import os; os.environ.get("FOO")' in the python shell

The result should be '1', but there is no output.


This patch fixes python-shell--tramp-with-environment and adds tests.
The python-tests-remote-path-1 test needs a real ssh remote connection
like REMOTE_TEMPORARY_FILE_DIRECTORY=/ssh:remote:/tmp/.


There is still a corner case: if python-shell-process-environment
contains an environment variable that already exists in the default
process-environment, the environment variable is not applied by tramp
for the remote Python shell. For example, the following test fails:

FOO=1 REMOTE_TEMPORARY_FILE_DIRECTORY=/ssh:remote:/tmp/ \
  make python-tests SELECTOR='"python-tests-remote-env"'

where FOO=1 is in both python-shell-process-environment and default
process-environment. This issue may need to be addressed in tramp.