Shepherd fails to start a system when given an incorrect form to the start field of any service

(simple-service

'shepherd-bug-repro

shepherd-root-service-type

(list (shepherd-service

(documentation "shepherd hang minimal repro")

(provision '(shepherd-bug-repro))

(requirement '())

(start #~('())))))

u--8<---------------cut here---------------end--------------->8---

? DO NOT BOOT ON A CRITICAL SYSTEM WITH THIS SERVICE, IT'LL BRICK IT ?

You can create a VM for this system and start it. The VM hangs after the

log line "creating /etc/machine-id...", before any shepherd service gets

started.

You get the same behaviour if you end up booting by misfortune a "real"

system having this service.

Instead of having the whole system to freeze, I'd expect shepherd to

fail the particular service having an incorrect start form.

I'm not sure what's happening here. I did not manage to diagnose this further,

the shepherd does not seem to be super chatty at this stage of the boot.

Tested on Shepherd 0.10.4 with the Guix revision

c5e63e19ac672f9e63fc8ee98fa9a16f978ce19c.

Jun 26 15:43:09 localhost vmunix: [ 3.574026] shepherd[1]: Exception caught while loading '/gnu/store/c44hd3gfksalrbsgc3a0ax4v9jmnkzb4-shepherd-shepherd-bug-repro.go': #<&compound-exception components: (#<&assertion-failure> #<&origin origin: #f> #<&message message: "Wrong type to apply: ~S"> #<&i

Jun 26 15:43:09 localhost vmunix: [ 3.574132] rritants irritants: (())> #<&exception-with-kind-and-args kind: wrong-type-arg args: (#f "Wrong type to apply: ~S" (()) (()))>)>

Jun 26 15:43:09 localhost vmunix: [ 3.583838] shepherd[1]: starting services...

Jun 26 15:43:09 localhost vmunix: [ 3.585444] shepherd[1]: Configuration successfully loaded from '/gnu/store/8cch4dv5ca1v0hsgyr6d8jay513x7d8g-shepherd.conf'.