bug#36378: Guix Cuirass Issue with Input channels

[Reza Alizadeh Majd]

Package: cuirass

adding additional inputs to cuirass specification with name started with `p` 
letter, fails the evaluation of specification. 


considering following specification: 

--8<---------------cut here---------------start------------->8---
(list 
  '((#:name . "hello-spec")
    (#:load-path-inputs . ("guix"))
    (#:package-path-inputs . ())
    (#:proc-input ."guix")
    (#:proc-file . "build-aux/cuirass/gnu-system.scm")
    (#:proc . cuirass-jobs)
    (#:proc-args . ((subset . "hello")
                    (systems . ("x86_64-linux"))))
    (#:inputs . (((#:name . "guix")
                  (#:url . "git://git.savannah.gnu.org/guix.git")
                  (#:load-path . ".")
                  (#:branch . "master")
                  (#:no-compile? . #t))
                 ((#:name . "pkginput")
                  (#:url . "git://git.savannah.gnu.org/guix/guix-cuirass.git")
                  (#:load-path . ".")
                  (#:branch . "master")
                  (#:no-compile? . #t))
                 ))))
--8<---------------cut here---------------end--------------->8---

we receive following error: 

--8<---------------cut here---------------start------------->8---
root@panther ~/ci# cuirass --listen=0.0.0.0 --port=8082 -D test.db -S tttt.scm 
...
2019-06-25T19:17:33 fetching input 'guix' of spec 'hello-spec'
2019-06-25T19:17:33 fetching input 'pkginput' of spec 'hello-spec'
2019-06-25T19:17:35 fetched input 'pkginput' of spec 'hello-spec' (commit 
"fed15b83b0b54d17057733935eb53e94e1a2c926")
2019-06-25T19:17:35 fetched input 'guix' of spec 'hello-spec' (commit 
"5fbb9f0b51a1caeb86009192654f650c5cb4d167")
2019-06-25T19:17:35 next evaluation in 300 seconds
2019-06-25T19:17:35 evaluating spec 'hello-spec'
Backtrace:
          17 (apply-smob/1 #<catch-closure 128b780>)
In ice-9/boot-9.scm:
    705:2 16 (call-with-prompt _ _ #<procedure default-prompt-handle…>)
In ice-9/eval.scm:
    619:8 15 (_ #(#(#<directory (guile-user) 1316140>)))
   293:34 14 (_ #(#(#(#(#(#(#(#(#(#(#(…) …) …) …) …) …) …) …) …) …) …))
    159:9 13 (_ _)
    619:8 12 (_ #(#(#(#<module (#{ g18}#) 1339640>) #<store-co…> …) …))
   626:19 11 (_ #(#(#(#<module (#{ g18}#) 1339640>) #<store-co…> …) …))
In guix/store.scm:
  1794:24 10 (run-with-store _ _ #:guile-for-build _ #:system _ # _)
In guix/channels.scm:
    498:2  9 (_ _)
    455:2  8 (_ _)
In guix/monads.scm:
    482:9  7 (_ _)
In guix/store.scm:
   1667:8  6 (_ _)
In guix/gexp.scm:
    708:2  5 (_ _)
In guix/monads.scm:
    482:9  4 (_ _)
In guix/gexp.scm:
   573:13  3 (_ _)
In guix/store.scm:
  1667:13  2 (_ _)
In guix/gexp.scm:
    210:2  1 (lower-object #f _ #:target _)
   189:36  0 (lookup-compiler #f)

guix/gexp.scm:189:36: In procedure lookup-compiler:
In procedure struct_vtable: Wrong type argument in position 1 (expecting 
struct): #f

Some deprecated features have been used.  Set the environment
variable GUILE_WARN_DEPRECATED to "detailed" and rerun the
program to get more information.  Set it to "no" to suppress
this message.
2019-06-25T19:17:36 failed to evaluate spec 'hello-spec'
--8<---------------cut here---------------end--------------->8---

but by just renaming the `pkginput` to something that is not starts with `p` 
word like `_pkginput` spec evaluation will succeed. 


--8<---------------cut here---------------start------------->8---
root@panther ~/ci# cuirass --listen=0.0.0.0 --port=8082 -D test.db -S bug.scm
...
2019-06-25T19:41:34 fetching input 'guix' of spec 'hello-spec'
2019-06-25T19:41:34 fetching input '_pkginput' of spec 'hello-spec'
2019-06-25T19:41:35 fetched input 'guix' of spec 'hello-spec' (commit 
"5fbb9f0b51a1caeb86009192654f650c5cb4d167")
2019-06-25T19:41:35 fetched input '_pkginput' of spec 'hello-spec' (commit 
"fed15b83b0b54d17057733935eb53e94e1a2c926")
2019-06-25T19:41:35 next evaluation in 300 seconds
2019-06-25T19:41:35 evaluating spec 'hello-spec'
warning:
building things during evaluation
'build-things' arguments: 
(("/gnu/store/h8fsfj550mikscspyg4x9fi7jgliq8qa-compute-guix-derivation.drv") 0)
Computing Guix derivation for 'x86_64-linux'... -
warning:
building things during evaluation
'build-things' arguments: 
(("/gnu/store/sz3l35mnfhphqnrgzg78k84chm3fys5i-profile.drv") 0)

Some deprecated features have been used.  Set the environment
variable GUILE_WARN_DEPRECATED to "detailed" and rerun the
program to get more information.  Set it to "no" to suppress
this message.
2019-06-25T19:42:35 evaluation 1 for 'hello-spec' completed
2019-06-25T19:42:35 building 1 jobs for 'hello-spec'
2019-06-25T19:42:35 evaluation 1 registered 1 new derivations
2019-06-25T19:42:35 building 1 derivations in batches of 200
2019-06-25T19:42:35 building batch of 200 derivations (0/1)
2019-06-25T19:42:35 done with 1 derivations
2019-06-25T19:42:35 outputs:
/gnu/store/md2plii4g5sk66wg9cgwc964l3xwhrm9-hello-2.10
2019-06-25T19:42:35 success: 1, fail: 0
--8<---------------cut here---------------end--------------->8---

--
Reza