fix: Adjust types of IQueryBuilder to properly allow joining with sub-query

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

3 files changed, 8 insertions, 4 deletions

diff --git a/lib/private/DB/QueryBuilder/Partitioned/PartitionedQueryBuilder.php b/lib/private/DB/QueryBuilder/Partitioned/PartitionedQueryBuilder.php
index 175b7c1a42e..9d351c1d3f1 100644
--- a/lib/private/DB/QueryBuilder/Partitioned/PartitionedQueryBuilder.php
+++ b/lib/private/DB/QueryBuilder/Partitioned/PartitionedQueryBuilder.php
@@ -185,7 +185,7 @@ class PartitionedQueryBuilder extends ShardedQueryBuilder {
 	}
 
 	public function leftJoin($fromAlias, $join, $alias, $condition = null): self {
-		return $this->join($fromAlias, $join, $alias, $condition, PartitionQuery::JOIN_MODE_LEFT);
+		return $this->join($fromAlias, (string)$join, $alias, $condition, PartitionQuery::JOIN_MODE_LEFT);
 	}
 
 	public function join($fromAlias, $join, $alias, $condition = null, $joinMode = PartitionQuery::JOIN_MODE_INNER): self {
diff --git a/lib/private/DB/QueryBuilder/QueryBuilder.php b/lib/private/DB/QueryBuilder/QueryBuilder.php
index 5c7e273c9ec..6cdf97b01e9 100644
--- a/lib/private/DB/QueryBuilder/QueryBuilder.php
+++ b/lib/private/DB/QueryBuilder/QueryBuilder.php
@@ -764,7 +764,7 @@ class QueryBuilder implements IQueryBuilder {
 	 * </code>
 	 *
 	 * @param string $fromAlias The alias that points to a from clause.
-	 * @param string $join The table name to join.
+	 * @param string|IQueryFunction $join The table name or sub-query to join.
 	 * @param string $alias The alias of the join table.
 	 * @param string|ICompositeExpression|null $condition The condition for the join.
 	 *
diff --git a/lib/public/DB/QueryBuilder/IQueryBuilder.php b/lib/public/DB/QueryBuilder/IQueryBuilder.php
index c21793a2421..22724c0c800 100644
--- a/lib/public/DB/QueryBuilder/IQueryBuilder.php
+++ b/lib/public/DB/QueryBuilder/IQueryBuilder.php
@@ -541,12 +541,13 @@ interface IQueryBuilder {
 	 * </code>
 	 *
 	 * @param string $fromAlias The alias that points to a from clause.
-	 * @param string $join The table name to join.
+	 * @param string|IQueryFunction $join The table name to join.
 	 * @param string $alias The alias of the join table.
 	 * @param string|ICompositeExpression|null $condition The condition for the join.
 	 *
 	 * @return $this This QueryBuilder instance.
 	 * @since 8.2.0
+	 * @since 30.0.0 Allow passing IQueryFunction as parameter for `$join` to allow join with a sub-query.
 	 *
 	 * @psalm-taint-sink sql $fromAlias
 	 * @psalm-taint-sink sql $join
@@ -1001,11 +1002,14 @@ interface IQueryBuilder {
 	public function getLastInsertId(): int;
 
 	/**
-	 * Returns the table name quoted and with database prefix as needed by the implementation
+	 * Returns the table name quoted and with database prefix as needed by the implementation.
+	 * If a query function is passed the function is casted to string,
+	 * this allows passing functions as sub-queries for join expression.
 	 *
 	 * @param string|IQueryFunction $table
 	 * @return string
 	 * @since 9.0.0
+	 * @since 24.0.0 accepts IQueryFunction as parameter
 	 */
 	public function getTableName($table);