On Mon, 27 Jun 2011 23:49:37 -0400, Austin Clements <amdragon@MIT.EDU> wrote: > Quoth Dmitry Kurochkin on Jun 28 at 5:03 am: > > > > The only way I know to > > > > reliably kill a child process is to open a pipe to it and have it exit > > > > on its own when it reads EOF. Unfortunately, I couldn't find a way to > > > > do this with an emacs daemon (it appears daemon mode aggressively > > > > cleans up things like pipes), but here's a different approach: > > > > > > > > coproc emacs --batch --eval "(while t (eval (read)))" > > > > EMACSFD=${COPROC[1]} > > > > trap "echo '(kill-emacs)' >&$EMACSFD" EXIT > > > > > > > > echo '(message "Hi")' >&$EMACSFD > > > > # ... > > > > > > > > This is, basically, a poor man's emacs server, but the coprocess pipe > > > > binds it tightly to the shell. If the shell exits for *any* reason, > > > > the pipe will be closed by the kernel, emacs will read an EOF, and > > > > exit. > > > > > > I like this idea. > > > > > > > The trap is there just to cleanly shut down in case of a normal > > > > exit [1]. > > > > > > For normal exit we should just put this into test_done. Otherwise it is > > > not a normal exit and we do not care about Emacs error message. No? > > > > > > > This also has the advantage that read-from-minibuffer still > > > > works: > > > > > > > > echo '(message (read-from-minibuffer ""))' >&$EMACSFD > > > > echo 'Test' >&$EMACSFD > > > > > > > > Thoughts? > > > > > > > > > > I like it and I will implement it. Thanks for the idea. > > > > > > > While implementing the idea, I stumbled upon a problem: we need to know > > when Emacs finished what we echoed or failed with an error. At the > > moment tests fail because they check for OUTPUT before Emacs creates it. > > > > We can tell Emacs to print some special marker and wait for it. But > > there may be exceptions and errors which may make it difficult. I did > > not found a good solution yet. Would love to hear your thoughts :) > > Oof, yes, of course. How about making the one-line poor man's emacs > server slightly less poor? Use a FIFO to communicate completion. > Something like, > > EMACSDONE=$TEST_DIRECTORY/emacsdone > mkfifo $EMACSDONE > coproc emacs --batch --eval '(while t (eval (read)) (write-region "\n" nil "'$EMACSDONE'" t 0))' > EMACSFD=${COPROC[1]} > > test_emacs() { > echo "$1" >&$EMACSFD > read <$EMACSDONE > } > > test_emacs '(sleep-for 2)' > test_emacs '(message "Hi")' > > echo '(kill-emacs)' >&$EMACSFD I am sure that would work, but I do not like the complexity. How about getting back to standard emacsclient and running a watchdog in the emacs? Like: (defun orphan-watchdog (pid) "Periodically check that the process with id PID is still running, quit if it terminated." (if (not (process-attributes pid)) (kill-emacs) (run-at-time "1 min" nil orphan-watchdog pid))) This function (or my other changes) do not work (by yet unknown reason :)), but you get the idea. Regards, Dmitry