lei: fix SIGPIPE on large result sets to pager

When dealing with large search results, we need to deal with
EPIPE not just from the pager, but also EPIPE or ECONNRESET
between lei_xsearch and lei2mail processes.

Without this fix, lei_xsearch processes could linger and get
stuck writing to dead lei2mail processes if a user aborts the
pager early during a large result set.

To ensure lei_xsearch processes don't linger around after
lei2mail workers all die, we must close $l2m->{-wq_s2} before
spawning lei_xsearch processes, since $l2m->{-wq_s2} is only
used in lei2mail workers.

For `git cat-file' processes, we also need to trigger
PublicInbox::Git->close to handle unpredictable destructor
ordering to avoid using uninitialized IO refs.  This combines
with the `git_to_mail' change to deal with process cleanup
handling from premature shutdowns.

To test all this, we can't just rely on a single message being
large, but also need to rely on the result set being large
enough to saturate the lei_xsearch -> lei2mail socket so we
rely on GIANT_INBOX_DIR once again.

4 files changed, 13 insertions, 3 deletions

diff --git a/lib/PublicInbox/Git.pm b/lib/PublicInbox/Git.pm
index 11712db2..292c359a 100644
--- a/lib/PublicInbox/Git.pm
+++ b/lib/PublicInbox/Git.pm
@@ -276,6 +276,7 @@ sub cat_async_step ($$) {
 
 sub cat_async_wait ($) {
         my ($self) = @_;
+        $self->close if !$self->{sock};
         my $inflight = $self->{inflight} or return;
         while (scalar(@$inflight)) {
                 cat_async_step($self, $inflight);
@@ -331,6 +332,7 @@ sub check_async_wait ($) {
         my ($self) = @_;
         return cat_async_wait($self) if $self->{-bc};
         my $ck = $self->{ck} or return;
+        $ck->close if !$ck->{sock};
         my $inflight = $ck->{inflight} or return;
         check_async_step($ck, $inflight) while (scalar(@$inflight));
 }
diff --git a/lib/PublicInbox/LeiOverview.pm b/lib/PublicInbox/LeiOverview.pm
index 066c40bd..129dabf8 100644
--- a/lib/PublicInbox/LeiOverview.pm
+++ b/lib/PublicInbox/LeiOverview.pm
@@ -212,7 +212,8 @@ sub ovv_each_smsg_cb { # runs in wq worker usually
                 sub {
                         my ($smsg, $mitem, $eml) = @_;
                         $smsg->{pct} = get_pct($mitem) if $mitem;
-                        $l2m->wq_io_do('write_mail', [], $smsg, $eml);
+                        eval { $l2m->wq_io_do('write_mail', [], $smsg, $eml) };
+                        $lei->fail($@) if $@ && !$!{ECONNRESET} && !$!{EPIPE};
                 }
         } elsif ($self->{fmt} =~ /\A(concat)?json\z/ && $lei->{opt}->{pretty}) {
                 my $EOR = ($1//'') eq 'concat' ? "\n}" : "\n},";
diff --git a/lib/PublicInbox/LeiToMail.pm b/lib/PublicInbox/LeiToMail.pm
index e80163e2..b73af68a 100644
--- a/lib/PublicInbox/LeiToMail.pm
+++ b/lib/PublicInbox/LeiToMail.pm
@@ -8,11 +8,13 @@ use v5.10.1;
 use parent qw(PublicInbox::IPC);
 use PublicInbox::Eml;
 use PublicInbox::IO;
+use PublicInbox::Git;
 use PublicInbox::Spawn qw(spawn);
 use IO::Handle; # ->autoflush
 use Fcntl qw(SEEK_SET SEEK_END O_CREAT O_EXCL O_WRONLY);
 use PublicInbox::Syscall qw(rename_noreplace);
 use autodie qw(open seek close);
+use Carp qw(croak);
 
 my %kw2char = ( # Maildir characters
         draft => 'D',
@@ -132,8 +134,12 @@ sub eml2mboxcl2 {
 
 sub git_to_mail { # git->cat_async callback
         my ($bref, $oid, $type, $size, $smsg) = @_;
-        my $self = delete $smsg->{l2m} // die "BUG: no l2m";
         $type // return; # called by PublicInbox::Git::close
+        my $self = delete $smsg->{l2m};
+        if (!defined($self)) {
+                return if $PublicInbox::Git::in_cleanup;
+                croak "BUG: no l2m (type=$type)";
+        }
         eval {
                 if ($type eq 'missing' &&
                           ($bref = $self->{-lms_rw}->local_blob($oid, 1))) {
diff --git a/lib/PublicInbox/LeiXSearch.pm b/lib/PublicInbox/LeiXSearch.pm
index 5443188d..6c8dfe10 100644
--- a/lib/PublicInbox/LeiXSearch.pm
+++ b/lib/PublicInbox/LeiXSearch.pm
@@ -20,7 +20,7 @@ use PublicInbox::LEI;
 use Fcntl qw(SEEK_SET F_SETFL O_APPEND O_RDWR);
 use PublicInbox::ContentHash qw(git_sha);
 use POSIX qw(strftime);
-use autodie qw(open read seek truncate);
+use autodie qw(close open read seek truncate);
 use PublicInbox::Syscall qw($F_SETPIPE_SZ);
 
 sub new {
@@ -543,6 +543,7 @@ sub do_query {
                 pipe($lei->{startq}, $lei->{au_done}) or die "pipe: $!";
                 fcntl($lei->{startq}, $F_SETPIPE_SZ, 4096) if $F_SETPIPE_SZ;
                 delete $l2m->{au_peers};
+                close(delete $l2m->{-wq_s2}); # share wq_s1 with lei_xsearch
         }
         $self->wq_workers_start('lei_xsearch', undef,
                                 $lei->oldset, { lei => $lei },