Merge remote-tracking branch 'origin/master' into lorelei

* origin/master: (58 commits)
  ds: flatten + reuse @events, epoll_wait style fixes
  ds: simplify EventLoop implementation
  check defined return value for localized slurp errors
  import: check for git->qx errors, clearer return values
  git: qx: avoid extra "local" for scalar context case
  search: remove {mset} option for ->mset method
  search: remove pointless {relevance} setting
  miscsearch: take reopen from Search and use it
  extsearch: unconditionally reopen on access
  extindex: allow using --all without EXTINDEX_DIR
  extindex: add undocumented --no-scan switch
  extindex: enable autoflush on STDOUT/STDERR
  extindex: various --watch signal handling fixes
  extindex: --watch for inotify-based updates
  eml: fix undefined vars on <Perl 5.28
  t/config: test --get-urlmatch for git <2.26
  default to CORE::warn in $SIG{__WARN__} handlers
  inbox: name variable for values loop iterator
  inboxidle: avoid needless syscalls on refresh
  inboxidle: clue users into resolving ENOSPC from inotify
  ...

1 files changed, 24 insertions, 11 deletions

diff --git a/lib/PublicInbox/InboxIdle.pm b/lib/PublicInbox/InboxIdle.pm
index 2737bbbd..35aed696 100644
--- a/lib/PublicInbox/InboxIdle.pm
+++ b/lib/PublicInbox/InboxIdle.pm
@@ -7,7 +7,6 @@
 package PublicInbox::InboxIdle;
 use strict;
 use parent qw(PublicInbox::DS);
-use Cwd qw(abs_path);
 use PublicInbox::Syscall qw(EPOLLIN EPOLLET);
 my $IN_MODIFY = 0x02; # match Linux inotify
 my $ino_cls;
@@ -22,28 +21,38 @@ require PublicInbox::In2Tie if $ino_cls;
 
 sub in2_arm ($$) { # PublicInbox::Config::each_inbox callback
         my ($ibx, $self) = @_;
-        my $dir = abs_path($ibx->{inboxdir});
-        if (!defined($dir)) {
-                warn "W: $ibx->{inboxdir} not watched: $!\n";
-                return;
-        }
+        my $dir = $ibx->{inboxdir};
         my $inot = $self->{inot};
         my $cur = $self->{pathmap}->{$dir} //= [];
+        my $lock = "$dir/".($ibx->version >= 2 ? 'inbox.lock' : 'ssoma.lock');
 
         # transfer old subscriptions to the current inbox, cancel the old watch
-        if (my $old_ibx = $cur->[0]) {
+        my $old_ibx = $cur->[0];
+        $cur->[0] = $ibx;
+        if ($old_ibx) {
                 $ibx->{unlock_subs} and
                         die "BUG: $dir->{unlock_subs} should not exist";
                 $ibx->{unlock_subs} = $old_ibx->{unlock_subs};
+
+                # Linux::Inotify2::Watch::name matches if watches are the
+                # same, no point in replacing a watch of the same name
+                if ($cur->[1]->name eq $lock) {
+                        $self->{on_unlock}->{$lock} = $ibx;
+                        return;
+                }
+                # rare, name changed (v1 inbox converted to v2)
                 $cur->[1]->cancel; # Linux::Inotify2::Watch::cancel
         }
-        $cur->[0] = $ibx;
 
-        my $lock = "$dir/".($ibx->version >= 2 ? 'inbox.lock' : 'ssoma.lock');
         if (my $w = $cur->[1] = $inot->watch($lock, $IN_MODIFY)) {
                 $self->{on_unlock}->{$w->name} = $ibx;
         } else {
                 warn "E: ".ref($inot)."->watch($lock, IN_MODIFY) failed: $!\n";
+                if ($!{ENOSPC} && $^O eq 'linux') {
+                        warn <<"";
+I: consider increasing /proc/sys/fs/inotify/max_user_watches
+
+                }
         }
 
         # TODO: detect deleted packs (and possibly other files)
@@ -54,6 +63,9 @@ sub refresh {
         $pi_cfg->each_inbox(\&in2_arm, $self);
 }
 
+# internal API for ease-of-use
+sub watch_inbox { in2_arm($_[1], $_[0]) };
+
 sub new {
         my ($class, $pi_cfg) = @_;
         my $self = bless {}, $class;
@@ -69,7 +81,7 @@ sub new {
         $self->{inot} = $inot;
         $self->{pathmap} = {}; # inboxdir => [ ibx, watch1, watch2, watch3...]
         $self->{on_unlock} = {}; # lock path => ibx
-        refresh($self, $pi_cfg);
+        refresh($self, $pi_cfg) if $pi_cfg;
         PublicInbox::FakeInotify::poll_once($self) if !$ino_cls;
         $self;
 }
@@ -80,7 +92,8 @@ sub event_step {
                 my @events = $self->{inot}->read; # Linux::Inotify2::read
                 my $on_unlock = $self->{on_unlock};
                 for my $ev (@events) {
-                        if (my $ibx = $on_unlock->{$ev->fullname}) {
+                        my $fn = $ev->fullname // next; # cancelled
+                        if (my $ibx = $on_unlock->{$fn}) {
                                 $ibx->on_unlock;
                         }
                 }