Attempt #3

query-engine/core/src/query_graph/mod.rs

@@ -575,30 +575,33 @@ impl QueryGraph {
 
     /// Inserts ordering edges into the graph to prevent interdependency issues when rotating
     /// nodes for `if`-flow nodes.
-    /// All sibling nodes of an if that are _not_ an if node themself or _not_ already connected
-    /// to the if node in any form (to prevent double edges) will be ordered below the if node
-    /// in execution predence.
+    ///
+    /// All sibling nodes of an if-node that are...
+    /// - ... not an `if`-flow node themself
+    /// - ... not already connected to the current `if`-flow node in any form (to prevent double edges)
+    /// - ... not connected to another `if`-flow node with control flow edges (indirect sibling)
+    /// will be ordered below the currently processed `if`-flow node in execution predence.
     ///
     /// ```text
     ///      ┌ ─ ─ ─ ─ ─ ─
-    /// ┌ ─ ─    Parent   │─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─
-    ///      └ ─ ─ ─ ─ ─ ─            │                 │
-    /// │           │
-    ///             │                 │                 │
-    /// │           │
-    ///             ▼                 ▼                 ▼
-    /// │    ┌ ─ ─ ─ ─ ─ ─     ┌ ─ ─ ─ ─ ─ ─     ┌ ─ ─ ─ ─ ─ ─
-    ///   ┌ ─      If     │       Sibling   │      Sibling If │
-    /// │    └ ─ ─ ─ ─ ─ ─     └ ─ ─ ─ ─ ─ ─     └ ─ ─ ─ ─ ─ ─
-    ///   │         │                 ▲
-    /// │           │                 │
-    ///   │         └────Inserted ────┘
+    /// ┌ ─ ─    Parent   │─ ─ ─ ─ ┬ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┬ ─ ─ ─ ─
+    ///      └ ─ ─ ─ ─ ─ ─                        │                       │
+    /// │           │              │                             │
+    ///             │                             │                       │
+    /// │           │              │                             │
+    ///             ▼              ▼              ▼              ▼        │
+    /// │    ┌ ─ ─ ─ ─ ─ ─  ┌ ─ ─ ─ ─ ─ ─  ┌ ─ ─ ─ ─ ─ ─  ┌ ─ ─ ─ ─ ─ ─
+    ///   ┌ ─      If     │    Sibling   │   Sibling If │   Sibling If │  │
+    /// │    └ ─ ─ ─ ─ ─ ─  └ ─ ─ ─ ─ ─ ─  └ ─ ─ ─ ─ ─ ─  └ ─ ─ ─ ─ ─ ─
+    ///   │         │              ▲                             │        │
+    /// │           │              │
+    ///   │         └────Inserted ─┘                       (Then / Else)  │
     /// │                Ordering
-    ///   │
-    /// │    ┌ ─ ─ ─ ─ ─ ─
-    ///   │     Already   │
-    /// └ ──▶│ connected
-    ///         sibling   │
+    ///   │                                                      ▼        │
+    /// │    ┌ ─ ─ ─ ─ ─ ─                                ┌ ─ ─ ─ ─ ─ ─
+    ///   │     Already   │                                  Indirect  │  │
+    /// └ ──▶│ connected                                  │  sibling    ◀─
+    ///         sibling   │                                ─ ─ ─ ─ ─ ─ ┘
     ///      └ ─ ─ ─ ─ ─ ─
     /// ```
     fn normalize_if_nodes(&mut self) -> QueryGraphResult<()> {
@@ -614,9 +617,20 @@ impl QueryGraph {
 
                     for (_, sibling) in siblings {
                         let possible_edge = self.graph.find_edge(node.node_ix, sibling.node_ix);
+                        let is_if_node_child = self
+                            .incoming_edges(&sibling)
+                            .into_iter()
+                            .find(|edge| {
+                                matches!(
+                                    self.edge_content(&edge).unwrap(),
+                                    QueryGraphDependency::Then | QueryGraphDependency::Else
+                                )
+                            })
+                            .is_some();
 
                         if sibling != node
                             && possible_edge.is_none()
+                            && !is_if_node_child
                             && !matches!(self.node_content(&sibling).unwrap(), Node::Flow(_))
                         {
                             self.create_edge(&node, &sibling, QueryGraphDependency::ExecutionOrder)?;