v2writable: read epoch on purge

A stand-alone tool for purge will won't know the epoch
if nothing was ->add()-ed before.

1 files changed, 7 insertions, 1 deletions

diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index ec28e510..1f17fe21 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -285,7 +285,13 @@ sub purge_oids {
         $self->done;
         my $pfx = "$self->{-inbox}->{mainrepo}/git";
         my $purges = [];
-        foreach my $i (0..$self->{epoch_max}) {
+        my $max = $self->{epoch_max};
+
+        unless (defined($max)) {
+                defined(my $latest = git_dir_latest($self, \$max)) or return;
+                $self->{epoch_max} = $max;
+        }
+        foreach my $i (0..$max) {
                 my $git_dir = "$pfx/$i.git";
                 -d $git_dir or next;
                 my $git = PublicInbox::Git->new($git_dir);