[PATCH] imapd: filter out unusable flags from search

[Eric Wong <e@80x24.org>]

Quiet down logs from -imapd when clients are blindly
sending some unsupported flag conditions (e.g. "DRAFT",
"DELETED") specified in RFC 3501.
---
 lib/PublicInbox/IMAPsearchqp.pm | 21 ++++++++++++++++++++-
 t/imapd.t                       |  8 +++++++-
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/lib/PublicInbox/IMAPsearchqp.pm b/lib/PublicInbox/IMAPsearchqp.pm
index 5c82faa5..190fefb9 100644
--- a/lib/PublicInbox/IMAPsearchqp.pm
+++ b/lib/PublicInbox/IMAPsearchqp.pm
@@ -162,11 +162,24 @@ sub msn_set {
 	uid_set($self, $seq_set);
 }
 
+# things that should not match
+sub impossible {
+	my ($self) = @_;
+	push @{$self->{xap}}, 'bytes:..0';
+	my $sql = $self->{sql} or return 1;
+	$$sql .= ' AND num < 0';
+}
+
 my $prd = Parse::RecDescent->new(<<'EOG');
 <nocheck>
 { my $q = $PublicInbox::IMAPsearchqp::q; }
 search_key : CHARSET(?) search_key1(s) { $return = $q }
-search_key1 : "ALL" | "RECENT" | "UNSEEN" | "NEW"
+
+# n.b. we silently ignore most per-message flags right now;
+# they're here for now to not dump parser errors.
+search_key1 : "ALL" | "ANSWERED" | "RECENT" | "UNSEEN" | "SEEN" | "NEW"
+	| "UNANSWERED" | "UNDELETED" | "UNDRAFT" | "UNFLAGGED"
+	| DELETED | DRAFT | FLAGGED | OLD
 	| OR_search_keys
 	| NOT_search_key
 	| LARGER_number
@@ -206,6 +219,12 @@ MSN_set : sequence_set { $q->msn_set($item{sequence_set}) }
 UID_set : "UID" sequence_set { $q->uid_set($item{sequence_set}) }
 LARGER_number : "LARGER" number { $q->xap_only("bytes:$item{number}..") }
 SMALLER_number : "SMALLER" number { $q->xap_only("bytes:..$item{number}") }
+
+DELETED : "DELETED" { $q->impossible }
+OLD : "OLD" { $q->impossible }
+FLAGGED : "FLAGGED" { $q->impossible }
+DRAFT : "DRAFT" { $q->impossible }
+
 # pass "NOT" through XXX is this right?
 OP_NOT : "NOT" { $q->xap_only('NOT') }
 NOT_search_key : OP_NOT search_key1
diff --git a/t/imapd.t b/t/imapd.t
index 4d627af7..8db72bd7 100644
--- a/t/imapd.t
+++ b/t/imapd.t
@@ -122,9 +122,11 @@ $ret = $mic->search('uid 1:1') or BAIL_OUT "SEARCH FAIL $@";
 is_deeply($ret, [ 1 ], 'search UID 1:1 works');
 $ret = $mic->search('uid 1:*') or BAIL_OUT "SEARCH FAIL $@";
 is_deeply($ret, [ 1 ], 'search UID 1:* works');
+$ret = $mic->search('DELETED') or BAIL_OUT "SEARCH FAIL $@";
+is_deeply($ret, [], 'searching for DELETED returns nothing');
 
 SKIP: {
-	skip 'Xapian missing', 7 if $level eq 'basic';
+	skip 'Xapian missing', 8 if $level eq 'basic';
 	my $x = $mic->search(qw(smaller 99999));
 	is_deeply($x, [1], 'SMALLER works with Xapian (hit)');
 	$x = $mic->search(qw(smaller 9));
@@ -137,6 +139,10 @@ SKIP: {
 
 	$x = $mic->search(qw(HEADER Message-ID testmessage@example.com));
 	is_deeply($x, [1], 'HEADER Message-ID works');
+
+	$x = $mic->search(qw(DRAFT HEADER Message-ID testmessage@example.com));
+	is_deeply($x, [], 'impossible (DRAFT) key filters out match');
+
 	$x = $mic->search(qw(HEADER Message-ID miss));
 	is_deeply($x, [], 'HEADER Message-ID can miss');