Make LoadBalancer domain handling more robust

* Cleanup setDomainPrefix() methods to handle existing LBs/DBs.
* This also makes it set just the prefix as the prefix rather
  than as the whole domain.
* Fix regression from 789a54a5f1 where "read" mode of
  tablePrefix()/dbSchema() still set the field.
* Make getConnectionRef() always have the domain set.
* Add a check in openConnection() for explicit local
  connections, treating $domain as false and avoiding
  openForeignConnection().

Bug: T145840
Change-Id: Idf392bd9992a215c4fa3bddf275562f3916596aa

1 files changed, 22 insertions, 0 deletions

diff --git a/tests/phpunit/includes/db/DatabaseTest.php b/tests/phpunit/includes/db/DatabaseTest.php
index d4be6e4fa0f3..134caf4abb1e 100644
--- a/tests/phpunit/includes/db/DatabaseTest.php
+++ b/tests/phpunit/includes/db/DatabaseTest.php
@@ -427,4 +427,26 @@ class DatabaseTest extends MediaWikiTestCase {
 		$this->assertEquals( $origSsl, $db->getFlag( DBO_SSL ) );
 		$this->assertEquals( $origTrx, $db->getFlag( DBO_TRX ) );
 	}
+
+	/**
+	 * @covers DatabaseBase::tablePrefix()
+	 * @covers DatabaseBase::dbSchema()
+	 */
+	public function testMutators() {
+		$old = $this->db->tablePrefix();
+		$this->assertType( 'string', $old, 'Prefix is string' );
+		$this->assertEquals( $old, $this->db->tablePrefix(), "Prefix unchanged" );
+		$this->assertEquals( $old, $this->db->tablePrefix( 'xxx' ) );
+		$this->assertEquals( 'xxx', $this->db->tablePrefix(), "Prefix set" );
+		$this->db->tablePrefix( $old );
+		$this->assertNotEquals( 'xxx', $this->db->tablePrefix() );
+
+		$old = $this->db->dbSchema();
+		$this->assertType( 'string', $old, 'Schema is string' );
+		$this->assertEquals( $old, $this->db->dbSchema(), "Schema unchanged" );
+		$this->assertEquals( $old, $this->db->dbSchema( 'xxx' ) );
+		$this->assertEquals( 'xxx', $this->db->dbSchema(), "Schema set" );
+		$this->db->dbSchema( $old );
+		$this->assertNotEquals( 'xxx', $this->db->dbSchema() );
+	}
 }