Merge branch 'main' into feat_migrate_ffi_to_stabby

Author: coderfender

Cargo.lock

@@ -584,17 +584,29 @@ impl LogicalPlan {
                 .map_elements(f)?
                 .update_data(|expr| LogicalPlan::Sort(Sort { expr, input, fetch })),
             LogicalPlan::Extension(Extension { node }) => {
-                // would be nice to avoid this copy -- maybe can
-                // update extension to just observer Exprs
-                let exprs = node.expressions().map_elements(f)?;
-                let plan = LogicalPlan::Extension(Extension {
-                    node: UserDefinedLogicalNode::with_exprs_and_inputs(
-                        node.as_ref(),
-                        exprs.data,
-                        node.inputs().into_iter().cloned().collect::<Vec<_>>(),
-                    )?,
-                });
-                Transformed::new(plan, exprs.transformed, exprs.tnr)
+                let raw_exprs = node.expressions();
+                if raw_exprs.is_empty() {
+                    // No expressions to transform — skip expensive clone of
+                    // all inputs and reconstruction via with_exprs_and_inputs.
+                    Transformed::no(LogicalPlan::Extension(Extension { node }))
+                } else {
+                    // TODO: a more general optimization would be to change
+                    // `UserDefinedLogicalNode::expressions()` to return
+                    // references (`&[Expr]`) instead of cloned `Vec<Expr>`,
+                    // and only clone + rebuild when the transform actually
+                    // modifies an expression. This would avoid the clone +
+                    // `with_exprs_and_inputs` rebuild even for non-empty
+                    // expression lists when the transform is a no-op.
+                    let exprs = raw_exprs.map_elements(f)?;
+                    let plan = LogicalPlan::Extension(Extension {
+                        node: UserDefinedLogicalNode::with_exprs_and_inputs(
+                            node.as_ref(),
+                            exprs.data,
+                            node.inputs().into_iter().cloned().collect::<Vec<_>>(),
+                        )?,
+                    });
+                    Transformed::new(plan, exprs.transformed, exprs.tnr)
+                }
             }
             LogicalPlan::TableScan(TableScan {
                 table_name,