Hi Eric,

Thank you for following up on this
despite your having more important matters on your shoulders :\

Le jeu. 17 févr. 2022 21h02 +0000, Eric Wong a écrit :
> > Looks like it is waiting on sysread() in
> > https://public-inbox.org/public-inbox.git/tree/t/lei-sigpipe.t#n35
> 
> OK, that makes more sense...

My tracing with print statements shows that sysread is passed
and that it is $tp->join which hangs:

[nixbld@localhost:/build]$ cat stderr.log
> lei-sigpipe: begin
> lei-sigpipe: start_script: done
> lei-sigpipe: close w: done
> lei-sigpipe: sysread
> lei-sigpipe: sysread: done
> lei-sigpipe: close r: done

[nixbld@localhost:/build]$ cat start_script.log
> start_script: begin
> start_script: fork
> start_script: pid!=0
> start_script: pid==0
> start_script: pid!=0: tail
> start_script: pid==0: if sub
> start_script: pid==0: exec lei

ps auxwwf | grep nixbld
> nixbld1   491489  0.1  0.0   5312  4036 ?        Ss   02:12   0:01      \_ bash -e /nix/store/qf3mzpvsmkrw963xchbivcci06078n13-builder.sh
> nixbld1   494307  0.0  0.1  16672 12616 ?        S    02:12   0:00          \_ perl -MExtUtils::Command::MM -MTest::Harness -e undef *Test::Harness::Switches; test_harness(0, 'blib/lib', 'blib/arch') t/lei-sigpipe.t
> nixbld1   494311  0.2  0.5  49320 40068 ?        S    02:12   0:02          |   \_ t/lei-sigpipe.t
> nixbld1   494445  0.0  0.0      0     0 ?        Z    02:12   0:00          |       \_ [/nix/store/176g] <defunct>
> nixbld1   494447  0.0  0.1  14388 10176 ?        S    02:12   0:00          |       \_ /nix/store/6wcdxh3h5jp9qgrccq3n71wnalca5mf5-perl-5.34.0/bin/perl -w -I/nix/store/6wcdxh3h5jp9qgrccq3n71wnalca5mf5-perl-5.34.0/lib/perl5/site_perl -I/nix/store/jibsc747pfzmyxp5lsqgzyvrs2lnkws6-perl5.34.0-Mail-IMAPClient-3.42/lib/perl5/site_perl -I/nix/st blib/script/lei q -q -t z:1..
> nixbld1   494427  0.1  0.5  50664 41892 ?        S    02:12   0:00          \_ lei-daemon /build/pi-lei-sigpipe-2750-0bv8/lei-daemon/xdg_run/lei/5.seq.sock
> nixbld1   494433  0.0  0.4  50260 39580 ?        S    02:12   0:00              \_ lei/store /build/pi-lei-sigpipe-2750-0bv8/lei-daemon/.local/share

The defunct process with truncated path "/nix/store/176g"
is points to /nix/store/176gh50y24c0lx2bnnmsvf9wazb73php-coreutils-9.0
It appears only when I export TAIL=${coreutils}/bin/tail
which does not workaround the hang.

This deadlock appears only when the test is run by nix,
it doesn't when I run it manually from a terminal
by entering the sandbox:

[nixbld@localhost:/]$ (cd /build/public-inbox-1.7.0; export PERL_INLINE_DIRECTORY=$PWD/inline-c; rm -rf $PERL_INLINE_DIRECTORY; mkdir $PERL_INLINE_DIRECTORY; prove -bvw t/lei-sigpipe.t )
> t/lei-sigpipe.t .. 
> ok 1 - lei import $TMPDIR/big.eml
> ok 2 - read one byte
> ok 3 - signaled 
> ok 4 - got SIGPIPE 
> ok 5 - read one byte
> ok 6 - signaled -f mboxcl2
> ok 7 - got SIGPIPE -f mboxcl2
> ok 8 - read one byte
> ok 9 - signaled -f text
> ok 10 - got SIGPIPE -f text
> ok 11 - lei daemon-pid (daemon-pid after t/lei-sigpipe.t:58)
> ok 12 - daemon running after t/lei-sigpipe.t:58
> ok 13 - lei daemon-kill (daemon-kill after t/lei-sigpipe.t:58)
> ok 14 - t/lei-sigpipe.t:58 daemon stopped
> ok 15 - t/lei-sigpipe.t:58 daemon XDG_RUNTIME_DIR/lei/errors.log empty
> 1..15
> ok
> All tests successful.
> Files=1, Tests=15,  8 wallclock secs ( 0.06 usr  0.08 sys +  3.55 cusr  2.81 csys =  6.50 CPU)
> Result: PASS