database: Fix various scalar and null types

Fix return values to match documentation
Provide fallback if no null value is allowed
Return from inside of try/finally makes it clear for static analyzer

Change-Id: I8bdfa453fc56dc50749cbd324b3d0d36e8e7065e

includes/libs/rdbms/database/Database.php

@@ -105,7 +105,7 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 	protected $flags;
 	/** @var array Current LoadBalancer tracking information */
 	protected $lbInfo = [];
-	/** @var string Current SQL query delimiter */
+	/** @var string|false Current SQL query delimiter */
 	protected $delimiter = ';';
 	/** @var array[] Current map of (table => (dbname, schema, prefix) map) */
 	protected $tableAliases = [];
@@ -2313,7 +2313,7 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 		$indexInfo = $this->indexInfo( $table, $index, $fname );
 
 		if ( !$indexInfo ) {
-			return null;
+			return false;
 		}
 
 		return !$indexInfo[0]->Non_unique;
@@ -2687,7 +2687,7 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 	) {
 		$fld = "GROUP_CONCAT($field SEPARATOR " . $this->addQuotes( $delim ) . ')';
 
-		return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
+		return '(' . $this->selectSQLText( $table, $fld, $conds, __METHOD__, [], $join_conds ) . ')';
 	}
 
 	/**
@@ -2893,7 +2893,7 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 	}
 
 	public function getServerName() {
-		return $this->serverName ?? $this->getServer();
+		return $this->serverName ?? $this->getServer() ?? 'unknown';
 	}
 
 	/**
@@ -4885,7 +4885,7 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 		}
 
 		try {
-			$error = $this->sourceStream(
+			return $this->sourceStream(
 				$fp,
 				$lineCallback,
 				$resultCallback,
@@ -4895,8 +4895,6 @@ abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAware
 		} finally {
 			fclose( $fp );
 		}
-
-		return $error;
 	}
 
 	public function setSchemaVars( $vars ) {

includes/libs/rdbms/database/DatabasePostgres.php

@@ -265,10 +265,12 @@ class DatabasePostgres extends Database {
 
 	public function lastErrno() {
 		if ( $this->lastResultHandle ) {
-			return pg_result_error_field( $this->lastResultHandle, PGSQL_DIAG_SQLSTATE );
-		} else {
-			return false;
+			$lastErrno = pg_result_error_field( $this->lastResultHandle, PGSQL_DIAG_SQLSTATE );
+			if ( $lastErrno !== false ) {
+				return (int)$lastErrno;
+			}
 		}
+		return 0;
 	}
 
 	protected function fetchAffectedRowCount() {
@@ -407,7 +409,7 @@ __INDEXATTR__;
 			")'";
 		$res = $this->query( $sql, $fname, $flags );
 		if ( !$res ) {
-			return null;
+			return false;
 		}
 
 		return $res->numRows() > 0;

includes/libs/rdbms/database/IDatabase.php

@@ -271,7 +271,7 @@ interface IDatabase {
 	 * Keys matching the IDatabase::LB_* constants are also used internally by subclasses
 	 *
 	 * @param array|string $nameOrArray The new array or the name of a key to set
-	 * @param array|null $value If $nameOrArray is a string, the new key value (null to unset)
+	 * @param array|mixed|null $value If $nameOrArray is a string, the new key value (null to unset)
 	 */
 	public function setLBInfo( $nameOrArray, $value = null );
 
@@ -293,7 +293,7 @@ interface IDatabase {
 	/**
 	 * Get the last time the connection may have been used for a write query
 	 *
-	 * @return int|float UNIX timestamp or false
+	 * @return int|float|false UNIX timestamp or false
 	 * @since 1.24
 	 */
 	public function lastDoneWrites();
@@ -2190,7 +2190,7 @@ interface IDatabase {
 	 * @param string $method Name of the calling method
 	 * @param int $timeout Acquisition timeout in seconds (0 means non-blocking)
 	 * @param int $flags Bit field of IDatabase::LOCK_* constants
-	 * @return bool Success
+	 * @return bool|float Success
 	 * @throws DBError If an error occurs, {@see query}
 	 */
 	public function lock( $lockName, $method, $timeout = 5, $flags = 0 );