[stable22] Allow casting query functions

lib/private/DB/QueryBuilder/ExpressionBuilder/ExpressionBuilder.php

@@ -425,11 +425,11 @@ public function literal($input, $type = null): ILiteral {
 	/**
 	 * Returns a IQueryFunction that casts the column to the given type
 	 *
-	 * @param string $column
+	 * @param string|IQueryFunction $column
 	 * @param mixed $type One of IQueryBuilder::PARAM_*
 	 * @return IQueryFunction
 	 */
-	public function castColumn(string $column, $type): IQueryFunction {
+	public function castColumn($column, $type): IQueryFunction {
 		return new QueryFunction(
 			$this->helper->quoteColumnName($column)
 		);

lib/private/DB/QueryBuilder/ExpressionBuilder/OCIExpressionBuilder.php

@@ -161,11 +161,11 @@ public function nonEmptyString($x): string {
 	/**
 	 * Returns a IQueryFunction that casts the column to the given type
 	 *
-	 * @param string $column
+	 * @param string|IQueryFunction $column
 	 * @param mixed $type One of IQueryBuilder::PARAM_*
 	 * @return IQueryFunction
 	 */
-	public function castColumn(string $column, $type): IQueryFunction {
+	public function castColumn($column, $type): IQueryFunction {
 		if ($type === IQueryBuilder::PARAM_STR) {
 			$column = $this->helper->quoteColumnName($column);
 			return new QueryFunction('to_char(' . $column . ')');

lib/private/DB/QueryBuilder/ExpressionBuilder/PgSqlExpressionBuilder.php

@@ -33,7 +33,7 @@ class PgSqlExpressionBuilder extends ExpressionBuilder {
 	/**
 	 * Returns a IQueryFunction that casts the column to the given type
 	 *
-	 * @param string $column
+	 * @param string|IQueryFunction $column
 	 * @param mixed $type One of IQueryBuilder::PARAM_*
 	 * @return IQueryFunction
 	 */

lib/public/DB/QueryBuilder/IExpressionBuilder.php

@@ -431,13 +431,13 @@ public function literal($input, $type = null): ILiteral;
 	/**
 	 * Returns a IQueryFunction that casts the column to the given type
 	 *
-	 * @param string $column
+	 * @param string|IQueryFunction $column
 	 * @param mixed $type One of IQueryBuilder::PARAM_*
 	 * @return IQueryFunction
 	 * @since 9.0.0
 	 *
 	 * @psalm-taint-sink sql $column
 	 * @psalm-taint-sink sql $type
 	 */
-	public function castColumn(string $column, $type): IQueryFunction;
+	public function castColumn($column, $type): IQueryFunction;
 }

tests/lib/DB/QueryBuilder/ExpressionBuilderDBTest.php

@@ -22,6 +22,7 @@
 namespace Test\DB\QueryBuilder;
 
 use OC\DB\QueryBuilder\Literal;
+use OCP\DB\QueryBuilder\IQueryBuilder;
 use Test\TestCase;
 
 /**
@@ -109,4 +110,37 @@ public function testILike($param1, $param2, $match) {
 		$result->closeCursor();
 		$this->assertEquals($match, $column);
 	}
+
+	public function testCastColumn(): void {
+		$appId = $this->getUniqueID('testing');
+		$this->createConfig($appId, '1', '4');
+
+		$query = $this->connection->getQueryBuilder();
+		$query->update('appconfig')
+			->set('configvalue',
+				$query->expr()->castColumn(
+					$query->createFunction(
+						'(' . $query->expr()->castColumn('configvalue', IQueryBuilder::PARAM_INT)
+						. ' + 1)'
+					)
+					, IQueryBuilder::PARAM_STR
+				)
+			)
+			->where($query->expr()->eq('appid', $query->createNamedParameter($appId)))
+			->andWhere($query->expr()->eq('configkey', $query->createNamedParameter('1')));
+
+		$result = $query->executeStatement();
+		$this->assertEquals(1, $result);
+	}
+
+	protected function createConfig($appId, $key, $value) {
+		$query = $this->connection->getQueryBuilder();
+		$query->insert('appconfig')
+			->values([
+				'appid' => $query->createNamedParameter($appId),
+				'configkey' => $query->createNamedParameter((string) $key),
+				'configvalue' => $query->createNamedParameter((string) $value),
+			])
+			->execute();
+	}
 }