Hi Chris, Thanks for debugging this!
Chris Marusich <cmmarus...@gmail.com> skribis: > From c3eea81846ae71a246e6b592be74062f4bf26474 Mon Sep 17 00:00:00 2001 > From: Chris Marusich <cmmarus...@gmail.com> > Date: Sun, 13 Feb 2022 14:15:14 -0800 > Subject: [PATCH] environment: Prevent PS1 from clobbering output in 'check'. > > Fixes: <https://issues.guix.gnu.org/51466>. > > * guix/scripts/environment.scm (child-shell-environment): In the script > executed the child shell, set PS1 to an empty value and then echo three > sentinel lines to try to "flush" the original PS1 value before printing the > environment variables. In the parent process, read and discard all lines up > to and including the last sentinel line. After that, read the remaining lines > as usual. [...] > + ;; Why print "GUIX_FLUSH" a few times? We are trying to "flush" the > + ;; original PS1 value to the port so we can read it (and discard it) > + ;; before we start reading the environment variables from the port. If > we > + ;; don't do this, the original PS1 value can sometimes get interleaved > + ;; into the output, which interferes with our parsing logic. It's a > hack, > + ;; but in practice it seems to do the job. If you know of a more > graceful > + ;; solution, please implement it! See: https://issues.guix.gnu.org/51466 > + "PS1=; for i in 1 2 3; do echo GUIX_FLUSH_$i; done; \ > +env || /usr/bin/env || set; echo GUIX-CHECK-DONE; read x; exit\n") So you confirm that a single “echo” is not enough, right? Perhaps we should unroll the ‘for’ loop for portability, to be on the safe side. Initially I tested with Bash, Zsh, and Fish: https://issues.guix.gnu.org/51285#0-lineno49 I think Fish has a very non-POSIX syntax, hence the suggestion to avoid ‘for’. I realized that setting PS1 could interfere with the logic below that checks for PS1. And since it doesn’t seem to help, perhaps we can remove “PS1=;”? Thoughts? Sorry to answer with yet more questions! Thanks, Ludo’.