1 files changed, 35 insertions, 0 deletions
diff --git a/rt/lib/RT/Record.pm b/rt/lib/RT/Record.pm
index fd238de16..313888cbc 100755
--- a/rt/lib/RT/Record.pm
+++ b/rt/lib/RT/Record.pm
@@ -1483,8 +1483,35 @@ sub _DeleteLink {
 }
 
 
+=head1 LockForUpdate
 
+In a database transaction, gains an exclusive lock on the row, to
+prevent race conditions.  On SQLite, this is a "RESERVED" lock on the
+entire database.
 
+=cut
+
+sub LockForUpdate {
+    my $self = shift;
+
+    my $pk = $self->_PrimaryKey;
+    my $id = @_ ? $_[0] : $self->$pk;
+    $self->_expire if $self->isa("DBIx::SearchBuilder::Record::Cachable");
+    if (RT->Config->Get('DatabaseType') eq "SQLite") {
+        # SQLite does DB-level locking, upgrading the transaction to
+        # "RESERVED" on the first UPDATE/INSERT/DELETE.  Do a no-op
+        # UPDATE to force the upgade.
+        return RT->DatabaseHandle->dbh->do(
+            "UPDATE " .$self->Table.
+                " SET $pk = $pk WHERE 1 = 0");
+    } else {
+        return $self->_LoadFromSQL(
+            "SELECT * FROM ".$self->Table
+                ." WHERE $pk = ? FOR UPDATE",
+            $id,
+        );
+    }
+}
 
 =head2 _NewTransaction  PARAMHASH
 
@@ -1512,6 +1539,11 @@ sub _NewTransaction {
         @_
     );
 
+    my $in_txn = RT->DatabaseHandle->TransactionDepth;
+    RT->DatabaseHandle->BeginTransaction unless $in_txn;
+
+    $self->LockForUpdate;
+
     my $old_ref = $args{'OldReference'};
     my $new_ref = $args{'NewReference'};
     my $ref_type = $args{'ReferenceType'};
@@ -1559,6 +1591,9 @@ sub _NewTransaction {
     if ( RT->Config->Get('UseTransactionBatch') and $transaction ) {
 	    push @{$self->{_TransactionBatch}}, $trans if $args{'CommitScrips'};
     }
+
+    RT->DatabaseHandle->Commit unless $in_txn;
+
     return ( $transaction, $msg, $trans );
 }