bug#63389: Cuirass stuck during evaluation

["Ludovic Courtès" <ludovic.courtes@inria.fr>]

Following the ‘core-updates’ merge, evaluations started by ‘cuirass
register’ seem to never complete.

The log shows things like “evaluating spec 'shepherd'” but there’s never
an indication of completion of failure.

The ‘cuirass register’ process spins at 100% after the ‘cuirass
evaluate’ process has failed, as if ‘evaluate’ in (cuirass base) did not
react properly to the end-of-file from the pipe:

--8<---------------cut here---------------start------------->8---
6220  dup2(0, 3)                        = 3
6220  dup2(52, 4)                       = 4
6220  dup2(48, 5)                       = 5
6220  dup2(3, 0)                        = 0
6220  dup2(4, 1)                        = 1
6220  dup2(5, 2)                        = 2
[…]
6220  execve("/home/ludo/.guix-profile/bin/guile", ["/home/ludo/.guix-profile/bin/guile", "--no-auto-compile", "-e", "main", "-s", "/data/src/cuirass/bin/cuirass", "evaluate", "dbname=test host=/tmp/ephemeralpg.NU2hSW", "17"], 0x238c9b0 /* 22 vars */) = 0
[…]
6203  read(47, "  2. &fix-hint: \"Make sure your list of channels\\ncontains one channel named @code{guix} providing the core of Guix.\"\n", 15324) = 118
6203  read(47, 0x7f1a9fbc34ba, 15206)   = -1 EAGAIN (Resource temporarily unavailable)
6203  epoll_ctl(12, EPOLL_CTL_MOD, 47, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=47, u64=47}}) = 0
6203  rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
6203  epoll_wait(12,  <unfinished ...>
6220  write(2, "  3. &error-location: #<<location> file: \"guix/channels.scm\" line: 584 column: 18>\n", 83) = 83
6203  <... epoll_wait resumed>[{events=EPOLLIN, data={u32=47, u64=47}}], 8, 101) = 1
6203  read(47, "  3. &error-location: #<<location> file: \"guix/channels.scm\" line: 584 column: 18>\n", 15206) = 83
6203  read(47, 0x7f1a9fbc350d, 15123)   = -1 EAGAIN (Resource temporarily unavailable)
6203  epoll_ctl(12, EPOLL_CTL_MOD, 47, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=47, u64=47}}) = 0
6203  rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
6203  epoll_wait(12,  <unfinished ...>
6220  exit_group(1)                     = ?
6221  <... futex resumed>)              = ?
6226  <... futex resumed>)              = ?
6224  <... read resumed> <unfinished ...>) = ?
6223  <... futex resumed>)              = ?
6222  <... futex resumed>)              = ?
6226  +++ exited with 1 +++
6224  +++ exited with 1 +++
6223  +++ exited with 1 +++
6221  +++ exited with 1 +++
6222  +++ exited with 1 +++
6203  <... epoll_wait resumed>[{events=EPOLLHUP, data={u32=51, u64=51}}], 8, 101) = 1
6203  epoll_ctl(12, EPOLL_CTL_MOD, 51, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=51, u64=51}}) = 0
6203  rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
6203  epoll_wait(12, [{events=EPOLLHUP, data={u32=51, u64=51}}], 8, 97) = 1
6203  epoll_ctl(12, EPOLL_CTL_MOD, 51, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=51, u64=51}}) = 0
6203  rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
6203  epoll_wait(12, [{events=EPOLLHUP, data={u32=51, u64=51}}], 8, 97) = 1
6203  epoll_ctl(12, EPOLL_CTL_MOD, 51, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=51, u64=51}}) = 0
6220  +++ exited with 1 +++
6203  --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=6220, si_uid=1000, si_status=1, si_utime=23 /* 0.23 s */, si_stime=5 /* 0.05 s */} ---
6203  rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
6203  epoll_wait(12, [{events=EPOLLHUP, data={u32=51, u64=51}}], 8, 97) = 1
6203  epoll_ctl(12, EPOLL_CTL_MOD, 51, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=51, u64=51}}) = 0
6203  rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
6203  epoll_wait(12, [{events=EPOLLHUP, data={u32=51, u64=51}}], 8, 97) = 1
6203  epoll_ctl(12, EPOLL_CTL_MOD, 51, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=51, u64=51}}) = 0
6203  rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
6203  epoll_wait(12, [{events=EPOLLHUP, data={u32=51, u64=51}}], 8, 96) = 1
6203  epoll_ctl(12, EPOLL_CTL_MOD, 51, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=51, u64=51}}) = 0
6203  rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
6203  epoll_wait(12, [{events=EPOLLHUP, data={u32=51, u64=51}}], 8, 96) = 1
6203  epoll_ctl(12, EPOLL_CTL_MOD, 51, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=51, u64=51}}) = 0
6203  rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
6203  epoll_wait(12, [{events=EPOLLHUP, data={u32=51, u64=51}}], 8, 96) = 1
6203  epoll_ctl(12, EPOLL_CTL_MOD, 51, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=51, u64=51}}) = 0
6203  rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
6203  epoll_wait(12, [{events=EPOLLHUP, data={u32=51, u64=51}}], 8, 96) = 1
6203  epoll_ctl(12, EPOLL_CTL_MOD, 51, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=51, u64=51}}) = 0
6203  rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
6203  epoll_wait(12, [{events=EPOLLHUP, data={u32=51, u64=51}}], 8, 96) = 1
6203  epoll_ctl(12, EPOLL_CTL_MOD, 51, {events=EPOLLIN|EPOLLRDHUP|EPOLLONESHOT, data={u32=51, u64=51}}) = 0
--8<---------------cut here---------------end--------------->8---

This is with:

--8<---------------cut here---------------start------------->8---
Generation 261	May 09 2023 09:50:33	(current)
  guix 649ce7b
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: 649ce7b433171a47e8a2819b849bfa88c736d0e9
--8<---------------cut here---------------end--------------->8---

To be continued…

Ludo’.