Hi Ludo’, Thank you for getting back to me!
l...@gnu.org (Ludovic Courtès) writes: > Hi Chris, and sorry for the delay! > > Chris Marusich <cmmarus...@gmail.com> skribis: > >> Backtrace: >> In ice-9/boot-9.scm: >> 157: 15 [catch #t #<catch-closure 26304a0> ...] >> In unknown file: >> ?: 14 [apply-smob/1 #<catch-closure 26304a0>] >> In ice-9/boot-9.scm: >> 63: 13 [call-with-prompt prompt0 ...] >> In ice-9/eval.scm: >> 432: 12 [eval # #] >> In ice-9/boot-9.scm: >> 2401: 11 [save-module-excursion #<procedure 264f940 at >> ice-9/boot-9.scm:4045:3 ()>] >> 4050: 10 [#<procedure 264f940 at ice-9/boot-9.scm:4045:3 ()>] >> 1724: 9 [%start-stack load-stack ...] >> 1729: 8 [#<procedure 2668ea0 ()>] >> In unknown file: >> ?: 7 [primitive-load "/root/guix/scripts/guix"] >> In guix/ui.scm: >> 1209: 6 [run-guix-command system "list-generations"] >> In ice-9/boot-9.scm: >> 157: 5 [catch srfi-34 #<procedure 52af180 at guix/ui.scm:425:2 ()> ...] >> 157: 4 [catch system-error ...] >> In guix/scripts/system.scm: >> 884: 3 [#<procedure 52ae750 at guix/scripts/system.scm:876:2 ()>] >> 818: 2 [process-command list-generations () ...] >> In guix/store.scm: >> 1182: 1 [run-with-store # ...] >> In unknown file: >> ?: 0 [#<unspecified> #<build-daemon 256.15 52b8e80>] >> >> ERROR: In procedure #<unspecified>: >> ERROR: Wrong type to apply: #<unspecified> > > This means that we’re trying to invoke #<unspecified>, but > #<unspecified> is not a procedure. > > Note that this is from within ‘run-to-store’, which is the procedure to > “run” a monadic value. So in effect, what happened is equivalent to: > > > scheme@(guile-user)> ,use(guix monads) > scheme@(guile-user)> ,use(guix store) > scheme@(guile-user)> (with-store s > (run-with-store s *unspecified*)) > ERROR: In procedure #<unspecified>: > ERROR: Wrong type to apply: #<unspecified> > > > The bug here is in fact a type error: ‘run-with-store’ expect a monadic > value, but what we have here is a regular value. > > To “fix” it, we need: > > > scheme@(guile-user)> (with-store s > (run-with-store s > (with-monad %store-monad (return *unspecified*)))) > > > … where ‘return’ procedure a monadic value from a normal value. > > In your case, ‘list-generations’ is not a monadic procedure (a procedure > that returns a monadic value), so in this patch: > > (run-with-store store > … > (list-generations)) > > … triggers this very type error. I see. I've read the sections in the manual about gexps, and I've peeked at the gexp code. I thought that basically I could use run-with-store to run any Guile code I want, but I seem to be missing something. I will try experimenting with monads and the store to learn more and hopefully avoid surprises like this going forward. > I imagine this may be more than you wanted to learn. ;-) > Monads in a dynamically typed setting are kinda annoying because of > this. I appreciate the info. Hopefully I will fully understand it soon. >> (define (process-command command args opts) >> "Process COMMAND, one of the 'guix system' sub-commands. ARGS is its >> argument list and OPTS is the option alist." >> - (case command >> - ((list-generations) >> - ;; List generations. No need to connect to the daemon, etc. >> - (let ((pattern (match args >> - (() "") >> - ((pattern) pattern) >> - (x (leave (_ "wrong number of arguments~%")))))) >> - (list-generations pattern))) >> - (else >> - (process-action command args opts)))) >> + (with-store store >> + (set-build-options-from-command-line store opts) >> + >> + (run-with-store store >> + (mbegin %store-monad >> + (set-guile-for-build (default-guile)) >> + (case command >> + ((list-generations) >> + (let ((pattern (match args >> + (() "") >> + ((pattern) pattern) >> + (x (leave (_ "wrong number of arguments~%")))))) >> + (list-generations pattern))) >> + (else >> + (process-action command args opts)))) >> + #:system (assoc-ref opts 'system)))) > > As the comment above suggests, the idea here was to avoid connecting to > the daemon for operations that do not need it, such as > ‘list-generations’. I think we should preserve this property. The reason I wanted to perform this refactoring in the first place is because I'd like to add a new procedure to guix/scripts/system.scm called 'switch-to-system-generation'. Because this new procedure calls other procedures which seem to require access to the store, I thought I would need to call 'switch-to-system-generation' via 'run-with-store'. Am I just confused? In particular, 'switch-to-system-generation' will eventually call the existing procedure 'grub-configuration-file' (defined in gnu/system/grub.scm). As I understand it, 'grub-configuration-file' returns a derivation that builds a GRUB configuration file. This existing 'grub-configuration-file' procedure does a lot with the store and gexps. I thought that if I didn't use 'run-with-store' to run 'switch-to-system-generation', it wouldn't work because 'grub-configuration-file' wouldn't work. > Thanks for your work! I’m sorry this is more painful than I thought. > :-/ > > Ludo’. I'm happy to help. I just wish I understood these monads better. And I wish I had more time to work on it! Anyway, I'll keep at it. -- Chris
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