> Date: Fri, 30 Aug 2024 23:43:57 +0900 > From: kobarity <kobar...@gmail.com> > Cc: 72...@debbugs.gnu.org > > Evgenii Klimov wrote: > > Eli Zaretskii <e...@gnu.org> writes: > > > > >> Date: Wed, 28 Aug 2024 00:13:25 +0100 > > >> From: Evgenii Klimov via "Bug reports for GNU Emacs, > > >> the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org> > > >> > > >> `with-temp-buffer' doesn't respect buffer-local environment variables, > > >> `exec-path' in this case. Which results in executables not being found, > > >> or the wrong versions of executables being picked up. E.g. if > > >> environment variable is modified via .dir-local file or direnv/envrc > > >> package. > > > > > > Hmm, this doesn't look clean to me: exec-path is just one variable, > > > what makes it special here? > > > > > > Moreover, it sounds like python-shell-with-environment, which > > > python-shell-prompt-detect calls, already attempts to have > > > buffer-local value of exec-path to be available to Python, so why > > > isn't that working for you? And if it isn't work, I think we should > > > amend python-shell-with-environment to do this, so we don't need to do > > > it "by hand". > > > > Indeed, my initial approach is too manual. > > > > Here the problem that I have: I don't use Python's "venv" module to > > create virtual environment for the project. Instead, I use GNU Guix's > > "guix shell" command [1] which provides augmented PATH and PYTHONPATH, > > etc. to link project's dependencies. Then, envrc.el package picks up > > these environment variables and makes them buffer-local project-wise > > (`exec-path' and `process-environment'). > > > > You are correct that `python-shell-with-environment' provides > > buffer-local variables, but `with-temp-buffer' treats `exec-path' and > > `process-environment' variables very specially. > > > > I didn't find this behavior in documentation, but look at this example: > > > > (setq-default exec-path (list "global" "list")) > > (setq-local exec-path (cons "local" > > (default-value 'exec-path))) > > (setq-default myvar (list "global" "list")) > > (setq-local myvar (cons "local" (default-value 'myvar))) > > > > (let ((exec-path exec-path) ; takes buffer-local > > (myvar myvar)) ; takes buffer-local > > (with-temp-buffer > > (insert (car exec-path) ; uses global > > "\n" > > (car myvar)) ; uses `let'-binded > > (buffer-string))) > > ;; => "global > > ;; local" > > > > (require 'cl-lib) > > (let ((myvar myvar)) > > ;; temporarily binds buffer-local value to global symbol > > (cl-letf (((default-value 'exec-path) exec-path)) > > (with-temp-buffer > > ;; global variable is used, but it's value is temporarily equal > > ;; to buffer-local value > > (insert (car exec-path) > > "\n" > > (car myvar)) > > (buffer-string)))) > > ;; => "local > > ;; local" > > > > It's a simplified and expanded version of > > `python-shell-with-environment' and `python-shell-prompt-detect'. As > > you can see, `exec-path' is treated differently inside of > > `with-temp-buffer' and `cl-letf' is needed to force `with-temp-buffer' > > to use buffer-local value of `exec-path'. > > > > In the new patch attached I show how this can be overcome. Don't know > > if you'll consider my use case too narrow and specific, but I'll be glad > > to hear your thoughts on this. > > > > [1] https://guix.gnu.org/en/manual/en/guix.html#Invoking-guix-environment > > Thank you for your explanation and the new patch. It helped me to > understand the problem correctly. I also confirmed that the new patch > resolves the issue. I don't think it's a special use case, as I > sometimes set `exec-path' locally using .dir-locals.el. I agree with > the new patch.
Thanks to both of you. I've now installed this on the emacs-30 release branch, and I'm therefore closing this bug.
