Search entities in all entity namespaces

Instead of assuming that all entities are in namespace 0 (which is only
true in a Wikidata-like installation, but not in a default Wikibase
installation, and even then only for items, not properties), use all
entity namespaces from the local configuration. (Use array_values to
make the keys numeric to make sure the database wrapper doesn’t try to
interpret the string keys ('item', 'property').)

Also, if we can’t find the entity, throw an exception instead of
returning count 0: it’s better to fail the import than to duplicate
statements.

Fixes #22.

src/PagePropsStatementCountLookup.php

@@ -14,13 +14,15 @@ public function __construct( LoadBalancer $loadBalancer ) {
 	}
 
 	public function getStatementCount( EntityId $entityId ) {
+		global $wgWBRepoSettings;
+
 		$db = $this->loadBalancer->getConnection( DB_MASTER );
 
 		$res = $db->selectRow(
 			array( 'page_props', 'page' ),
 			array( 'pp_value' ),
 			array(
-				'page_namespace' => 0,
+				'page_namespace' => array_values( $wgWBRepoSettings['entityNamespaces'] ),
 				'page_title' => $entityId->getSerialization(),
 				'pp_propname' => 'wb-claims'
 			),
@@ -32,7 +34,7 @@ public function getStatementCount( EntityId $entityId ) {
 		$this->loadBalancer->closeConnection( $db );
 
 		if ( $res === false ) {
-			return 0;
+			throw new Exception( "Could not find entity in page_props!" );
 		}
 
 		return (int)$res->pp_value;