wip: Fix sourcenetwork#486, wrapped scanNode bug by making multiscanN…

…ode adhere to

plan node and be non-explainable.

query/graphql/planner/operations.go

@@ -21,6 +21,7 @@ var (
 	_ planNode = (*groupNode)(nil)
 	_ planNode = (*hardLimitNode)(nil)
 	_ planNode = (*headsetScanNode)(nil)
+	_ planNode = (*multiScanNode)(nil)
 	_ planNode = (*parallelNode)(nil)
 	_ planNode = (*pipeNode)(nil)
 	_ planNode = (*renderLimitNode)(nil)

query/graphql/planner/scan.go

@@ -158,20 +158,20 @@ func (p *Planner) Scan(versioned bool) *scanNode {
 // we call Next() on the underlying scanNode only
 // once every 2 Next() calls on the multiScan
 type multiScanNode struct {
-	*scanNode
+	scanNode   *scanNode
 	numReaders int
 	numCalls   int
 
 	lastBool bool
 	lastErr  error
 }
 
-func (n *multiScanNode) addReader() {
-	n.numReaders++
+func (n *multiScanNode) Init() error {
+	return n.scanNode.Init()
 }
 
-func (n *multiScanNode) Source() planNode {
-	return n.scanNode
+func (n *multiScanNode) Start() error {
+	return n.scanNode.Start()
 }
 
 // Next only calls Next() on the underlying
@@ -190,3 +190,27 @@ func (n *multiScanNode) Next() (bool, error) {
 
 	return n.lastBool, n.lastErr
 }
+
+func (n *multiScanNode) Value() map[string]interface{} {
+	return n.scanNode.documentIterator.Value()
+}
+
+func (n *multiScanNode) Spans(spans core.Spans) {
+	n.scanNode.Spans(spans)
+}
+
+func (n *multiScanNode) Source() planNode {
+	return n.scanNode
+}
+
+func (n *multiScanNode) Kind() string {
+	return "multiScanNode"
+}
+
+func (n *multiScanNode) Close() error {
+	return n.scanNode.Close()
+}
+
+func (n *multiScanNode) addReader() {
+	n.numReaders++
+}

tests/integration/query/explain/with_count_test.go

@@ -186,11 +186,6 @@ func TestExplainQueryOneToManyMultipleWithCounts(t *testing.T) {
 											"collectionID":   "3",
 											"collectionName": "author",
 											"filter":         nil,
-											"scanNode": dataMap{
-												"collectionID":   "3",
-												"collectionName": "author",
-												"filter":         nil,
-											},
 										},
 									},
 								},
@@ -200,11 +195,6 @@ func TestExplainQueryOneToManyMultipleWithCounts(t *testing.T) {
 											"collectionID":   "3",
 											"collectionName": "author",
 											"filter":         nil,
-											"scanNode": dataMap{
-												"collectionID":   "3",
-												"collectionName": "author",
-												"filter":         nil,
-											},
 										},
 									},
 								},