dev/core#1862 Skip cache tables during merge, rely on cache managemen…

…t processes

We later call Contact.create on both contacts so that should manage the caches for this update 'as well as for any other update'
and solve the bug + reduce locking queries

CRM/Dedupe/Merger.php

@@ -225,6 +225,11 @@ public static function cidRefs() {
     }
 
     $contactReferences = $coreReferences = CRM_Core_DAO::getReferencesToContactTable();
+    foreach (['civicrm_group_contact_cache', 'civicrm_acl_cache', 'civicrm_acl_contact_cache'] as $tableName) {
+      // Don't merge cache tables. These should be otherwise cleared at some point in the dedupe
+      // but they are prone to locking to let's not touch during the dedupe.
+      unset($contactReferences[$tableName], $coreReferences[$tableName]);
+    }
 
     CRM_Utils_Hook::merge('cidRefs', $contactReferences);
     if ($contactReferences !== $coreReferences) {

tests/phpunit/api/v3/JobTest.php

@@ -573,11 +573,27 @@ public function testBatchMergeMergesGroups() {
     foreach ($groupResult['values'] as $groupValues) {
       $this->assertEquals($contactID, $groupValues['contact_id']);
       $this->assertEquals('Added', $groupValues['status']);
-      $this->assertTrue(in_array($groupValues['group_id'], $expectedGroups));
+      $this->assertContains($groupValues['group_id'], $expectedGroups);
 
     }
   }
 
+  /**
+   * Test that we handle cache entries without clashes.
+   */
+  public function testMergeCaches() {
+    $contactID = $this->individualCreate();
+    $contact2ID = $this->individualCreate();
+    $groupID = $this->groupCreate();
+    $this->callAPISuccess('GroupContact', 'create', ['group_id' => $groupID, 'contact_id' => $contactID]);
+    $this->callAPISuccess('GroupContact', 'create', ['group_id' => $groupID, 'contact_id' => $contact2ID]);
+    CRM_Core_DAO::executeQuery("INSERT INTO civicrm_group_contact_cache(group_id, contact_id) VALUES
+      ($groupID, $contactID),
+      ($groupID, $contact2ID)
+    ");
+    $this->callAPISuccess('Job', 'process_batch_merge', ['mode' => 'safe']);
+  }
+
   /**
    * Test the decisions made for addresses when merging.
    *