v2writable: detect and use previous partition count

We need to detect the number of partitions the repository was
created with to ensure Xapian DBs can work across different
machines (or even CPU affinity changes) without leaving messages
unaffected by search.

1 files changed, 10 insertions, 1 deletions

diff --git a/t/v2writable.t b/t/v2writable.t
index 2d35aca3..404c8651 100644
--- a/t/v2writable.t
+++ b/t/v2writable.t
@@ -30,7 +30,11 @@ my $mime = PublicInbox::MIME->create(
         body => "hello world\n",
 );
 
-my $im = PublicInbox::V2Writable->new($ibx, 1);
+my $im = eval {
+        local $ENV{NPROC} = '1';
+        PublicInbox::V2Writable->new($ibx, 1);
+};
+is($im->{partitions}, 1, 'one partition when forced');
 ok($im->add($mime), 'ordinary message added');
 
 if ('ensure git configs are correct') {
@@ -182,5 +186,10 @@ EOF
         }
         is_deeply([sort keys %nn], [sort keys %uniq]);
 };
+{
+        local $ENV{NPROC} = 2;
+        $im = PublicInbox::V2Writable->new($ibx, 1);
+        is($im->{partitions}, 1, 'detected single partition from previous');
+}
 
 done_testing();