Merge branch 'learn'

* learn:
  doc: add public-inbox-learn(1) manpage
  mda: support multiple List-ID matches
  mda: prepare for multiple destinations
  inboxwritable: add assert_usable_dir sub
  mda: skip MIME parsing if spam
  mda: hoist out mda_filter_adjust
  filter/base: remove MAX_MID_SIZE constant
  mda: hoist out List-ID handling and reuse in -learn
  learn: hoist out remove_or_add subroutine
  learn: GIT_COMMITTER_<NAME|EMAIL> may be "" or "0"
  learn: update usage statement
  learn: only map recipient list on "ham" or "rm"
  learn: support multiple To/Cc headers

diff --combined t/v2writable.t
index 2b82576878e13b9def584dfe5578352f4c28a4a2,06dafe98e1ed65fdbd2fd7337ecc6c5bd34f25de..bfe17d0a843a7b33ec4b17c1c3079c042cc312b2
--- 1/t/v2writable.t
--- 2/t/v2writable.t
+++ b/t/v2writable.t
@@@ -115,7 -115,6 +115,7 @@@ if ('ensure git configs are correct') 
  
  {
        $mime->header_set('Message-Id', '<abcde@1>', '<abcde@2>');
 +      $mime->header_set('X-Alt-Message-Id', '<alt-id-for-nntp>');
        $mime->header_set('References', '<zz-mid@b>');
        ok($im->add($mime), 'message with multiple Message-ID');
        $im->done;
@@@ -128,21 -127,6 +128,21 @@@
        is($mset2->size, 1, 'message found by second MID');
        is((($mset1->items)[0])->get_docid, (($mset2->items)[0])->get_docid,
                'same document') if ($mset1->size);
 +
 +      my $alt = $srch->reopen->query('m:alt-id-for-nntp', { mset => 1 });
 +      is($alt->size, 1, 'message found by alt MID (NNTP)');
 +      is((($alt->items)[0])->get_docid, (($mset1->items)[0])->get_docid,
 +              'same document') if ($mset1->size);
 +      $mime->header_set('X-Alt-Message-Id');
 +
 +      my %uniq;
 +      for my $mid (qw(abcde@1 abcde@2 alt-id-for-nntp)) {
 +              my $msgs = $ibx->over->get_thread($mid);
 +              my $key = join(' ', sort(map { $_->{num} } @$msgs));
 +              $uniq{$key}++;
 +      }
 +      is(scalar(keys(%uniq)), 1, 'all alt Message-ID queries give same smsg');
 +      is_deeply([values(%uniq)], [3], '3 queries, 3 results');
  }
  
  {
@@@ -276,4 -260,16 +276,16 @@@ EO
        $im->done;
  }
  
+ my $tmp = {
+       inboxdir => "$inboxdir/non-existent/subdir",
+       name => 'nope',
+       version => 2,
+       -primary_address => 'test@example.com',
+ };
+ eval {
+       my $nope = PublicInbox::V2Writable->new($tmp);
+       $nope->add($mime);
+ };
+ ok($@, 'V2Writable fails on non-existent dir');
+ 
  done_testing();