v2writable: get rid of {reindex_pipe} field

Since normal per-epoch indexing no longer holds a "git log"
process open, we don't need to worry about not sharing the
pipe with forked shards when we restart the indexer.

While we're in the area, better describe what `unindex' does,
since it's a rarely-used but necessary code path.

1 files changed, 4 insertions, 7 deletions

diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index a85f9e1f..c59ead39 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -848,8 +848,6 @@ sub content_exists ($$$) {
 
 sub atfork_child {
         my ($self) = @_;
-        my $fh = delete $self->{reindex_pipe};
-        close $fh if $fh;
         if (my $shards = $self->{idx_shards}) {
                 $_->atfork_child foreach @$shards;
         }
@@ -1081,7 +1079,6 @@ sub sync_prepare ($$$) {
         my $reindex_heads = last_commits($self, $epoch_max) if $sync->{reindex};
 
         for (my $i = $epoch_max; $i >= 0; $i--) {
-                die 'BUG: already indexing!' if $self->{reindex_pipe};
                 my $git_dir = git_dir_n($self, $i);
                 -d $git_dir or next; # missing epochs are fine
                 my $git = PublicInbox::Git->new($git_dir);
@@ -1161,6 +1158,8 @@ sub unindex_oid ($$;$) {
         }
 }
 
+# this is rare, it only happens when we get discontiguous history in
+# a mirror because the source used -purge or -edit
 sub unindex ($$$$) {
         my ($self, $sync, $git, $unindex_range) = @_;
         my $unindexed = $self->{unindexed} ||= {}; # $mid0 => $num
@@ -1168,12 +1167,11 @@ sub unindex ($$$$) {
         # order does not matter, here:
         my @cmd = qw(log --raw -r
                         --no-notes --no-color --no-abbrev --no-renames);
-        my $fh = $self->{reindex_pipe} = $git->popen(@cmd, $unindex_range);
+        my $fh = $git->popen(@cmd, $unindex_range);
         while (<$fh>) {
                 /\A:\d{6} 100644 $OID ($OID) [AM]\tm$/o or next;
                 unindex_oid($self, $1, $unindexed);
         }
-        delete $self->{reindex_pipe};
         close $fh or die "git log failed: \$?=$?";
 
         return unless $sync->{-opt}->{prune};
@@ -1203,10 +1201,9 @@ sub index_epoch ($$$) {
         my ($self, $sync, $i) = @_;
 
         my $git_dir = git_dir_n($self, $i);
-        die 'BUG: already reindexing!' if $self->{reindex_pipe};
         -d $git_dir or return; # missing epochs are fine
         my $git = PublicInbox::Git->new($git_dir);
-        if (my $unindex_range = delete $sync->{unindex_range}->{$i}) {
+        if (my $unindex_range = delete $sync->{unindex_range}->{$i}) { # rare
                 unindex($self, $sync, $git, $unindex_range);
         }
         defined(my $stk = $sync->{stacks}->[$i]) or return;