Merge cockroachdb#40616

craig[bot] · RaduBerinde · craig[bot] · commit a41355dabc98 · 2019-09-10T16:46:40.000Z
40616: sql: fix getPlanColumns for hookFnNode r=RaduBerinde a=RaduBerinde `getPlanColumns` allows the caller to directly mutate the columns of a `hookFnNode`; but these columns can be defined globally and should not be modified in place. Fixes cockroachdb#40585. Release note: None Co-authored-by: Radu Berinde <radu@cockroachlabs.com>
diff --git a/pkg/sql/plan_columns.go b/pkg/sql/plan_columns.go
@@ -49,8 +49,6 @@ func getPlanColumns(plan planNode, mut bool) sqlbase.ResultColumns {
 		return n.columns
 	case *groupNode:
 		return n.columns
-	case *hookFnNode:
-		return n.header
 	case *joinNode:
 		return n.columns
 	case *ordinalityNode:
@@ -120,6 +118,11 @@ func getPlanColumns(plan planNode, mut bool) sqlbase.ResultColumns {
 	case *exportNode:
 		return n.getColumns(mut, sqlbase.ExportColumns)
 
+	// The columns in the hookFnNode are returned by the hook function; we don't
+	// know if they can be modified in place or not.
+	case *hookFnNode:
+		return n.getColumns(mut, n.header)
+
 	// Nodes that have the same schema as their source or their
 	// valueNode helper.
 	case *bufferNode:
diff --git a/pkg/sql/planhook.go b/pkg/sql/planhook.go
@@ -110,6 +110,8 @@ func AddWrappedPlanHook(f wrappedPlanHookFn) {
 // provided function during Start and serves the results it returns over the
 // channel.
 type hookFnNode struct {
+	optColumnsSlot
+
 	f        PlanHookRowFn
 	header   sqlbase.ResultColumns
 	subplans []planNode
