Fix improper filtering behavior in ConpherenceParticipantQuery

Summary:
Pathway to D17685. This fixes an issue idenified in D17731: if any caller ever queried for more than one participant, some results could get thrown away by re-keying the results on thread PHID: two different participants can be members of the same thread!

This also fixes an issue from D17683, where a `needParticipantCache()` callsite was overlooked.

Test Plan:
  - Viewed Conpherence dropdown.
  - Sent messages, saw unread count / thread order still work properly.

Reviewers: chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D17732

Author: epriestley

src/applications/conpherence/conduit/ConpherenceQueryThreadConduitAPIMethod.php

@@ -36,8 +36,7 @@ protected function execute(ConduitAPIRequest $request) {
     $offset = $request->getValue('offset');
 
     $query = id(new ConpherenceThreadQuery())
-      ->setViewer($user)
-      ->needParticipantCache(true);
+      ->setViewer($user);
 
     if ($ids) {
       $conpherences = $query
@@ -57,7 +56,7 @@ protected function execute(ConduitAPIRequest $request) {
         ->setLimit($limit)
         ->setOffset($offset)
         ->execute();
-      $conpherence_phids = array_keys($participation);
+      $conpherence_phids = mpull($participation, 'getConpherencePHID');
       $query->withPHIDs($conpherence_phids);
       $conpherences = $query->execute();
       $conpherences = array_select_keys($conpherences, $conpherence_phids);

src/applications/conpherence/controller/ConpherenceListController.php

@@ -151,6 +151,7 @@ private function loadDefaultParticipation($limit) {
       ->withParticipantPHIDs(array($viewer->getPHID()))
       ->setLimit($limit)
       ->execute();
+    $all_participation = mpull($all_participation, null, 'getConpherencePHID');
 
     return array(
       'all_participation' => $all_participation,

src/applications/conpherence/controller/ConpherenceNotificationPanelController.php

@@ -12,6 +12,7 @@ public function handleRequest(AphrontRequest $request) {
       ->withParticipantPHIDs(array($user->getPHID()))
       ->setLimit(5)
       ->execute();
+    $participant_data = mpull($participant_data, null, 'getConpherencePHID');
 
     if ($participant_data) {
       $conpherences = id(new ConpherenceThreadQuery())

src/applications/conpherence/query/ConpherenceParticipantQuery.php

@@ -25,22 +25,7 @@ public function execute() {
       $this->buildOrderClause($conn),
       $this->buildLimitClause($conn));
 
-    $participants = $table->loadAllFromArray($data);
-
-    // TODO: Fix this, it's bogus.
-    if ('garbage') {
-      if (count($this->participantPHIDs) !== 1) {
-        throw new Exception(
-          pht(
-            'This query only works when querying for exactly one participant '.
-            'PHID!'));
-      }
-      // This will throw results away if we aren't doing a query for exactly
-      // one participant PHID.
-      $participants = mpull($participants, null, 'getConpherencePHID');
-    }
-
-    return $participants;
+    return $table->loadAllFromArray($data);
   }
 
   protected function buildWhereClause(AphrontDatabaseConnection $conn) {