chore: funcRunningDiff don't panic when series is empty

pkg/query-service/app/traces/tracedetail/waterfall.go

@@ -1,7 +1,6 @@
 package tracedetail
 
 import (
-	"maps"
 	"slices"
 	"sort"
 
@@ -64,22 +63,26 @@ func findIndexForSelectedSpanFromPreOrder(spans []*model.Span, selectedSpanId st
 	return selectedSpanIndex
 }
 
-func getPathFromRootToSelectedSpanId(node *model.Span, selectedSpanId string) (bool, []string) {
+func getPathFromRootToSelectedSpanId(node *model.Span, selectedSpanId string, uncollapsedSpans []string, isSelectedSpanIDUnCollapsed bool) (bool, []string) {
 	spansFromRootToNode := []string{}
 
-	spansFromRootToNode = append(spansFromRootToNode, node.SpanID)
 	if node.SpanID == selectedSpanId {
+		if isSelectedSpanIDUnCollapsed && !slices.Contains(uncollapsedSpans, node.SpanID) {
+			spansFromRootToNode = append(spansFromRootToNode, node.SpanID)
+		}
 		return true, spansFromRootToNode
 	}
 
 	isPresentInSubtreeForTheNode := false
 	for _, child := range node.Children {
-		isPresentInThisSubtree, _spansFromRootToNode := getPathFromRootToSelectedSpanId(child, selectedSpanId)
+		isPresentInThisSubtree, _spansFromRootToNode := getPathFromRootToSelectedSpanId(child, selectedSpanId, uncollapsedSpans, isSelectedSpanIDUnCollapsed)
 		// if the interested node is present in the given subtree then add the span node to uncollapsed node list
 		if isPresentInThisSubtree {
+			if !slices.Contains(uncollapsedSpans, node.SpanID) {
+				spansFromRootToNode = append(spansFromRootToNode, node.SpanID)
+			}
 			isPresentInSubtreeForTheNode = true
 			spansFromRootToNode = append(spansFromRootToNode, _spansFromRootToNode...)
-			break
 		}
 	}
 	return isPresentInSubtreeForTheNode, spansFromRootToNode
@@ -89,7 +92,7 @@ func getPathFromRootToSelectedSpanId(node *model.Span, selectedSpanId string) (b
 // throughout the recursion. Per-call state (level, isPartOfPreOrder, etc.)
 // is passed as direct arguments.
 type traverseOpts struct {
-	uncollapsedSpans map[string]struct{}
+	uncollapsedSpans []string
 	selectedSpanID   string
 }
 
@@ -131,7 +134,7 @@ func traverseTrace(span *model.Span, opts traverseOpts, level uint64, isPartOfPr
 		preOrderTraversal = append(preOrderTraversal, &nodeWithoutChildren)
 	}
 
-	_, isAlreadyUncollapsed := opts.uncollapsedSpans[span.SpanID]
+	isAlreadyUncollapsed := slices.Contains(opts.uncollapsedSpans, span.SpanID)
 	for index, child := range span.Children {
 		_childTraversal := traverseTrace(child, opts, level+1, isPartOfPreOrder && isAlreadyUncollapsed, index != (len(span.Children)-1))
 		preOrderTraversal = append(preOrderTraversal, _childTraversal...)
@@ -166,28 +169,16 @@ func GetSelectedSpans(uncollapsedSpans []string, selectedSpanID string, traceRoo
 
 	var preOrderTraversal = make([]*model.Span, 0)
 	var rootServiceName, rootServiceEntryPoint string
-
-	// create a map of uncollapsed spans for quick lookup
-	uncollapsedSpanMap := make(map[string]struct{})
-	for _, spanID := range uncollapsedSpans {
-		uncollapsedSpanMap[spanID] = struct{}{}
-	}
+	updatedUncollapsedSpans := uncollapsedSpans
 
 	selectedSpanIndex := -1
 	for _, rootSpanID := range traceRoots {
 		if rootNode, exists := spanIdToSpanNodeMap[rootSpanID.SpanID]; exists {
-			present, spansFromRootToNode := getPathFromRootToSelectedSpanId(rootNode, selectedSpanID)
-			if present {
-				for _, spanID := range spansFromRootToNode {
-					if selectedSpanID == spanID && !isSelectedSpanIDUnCollapsed {
-						continue
-					}
-					uncollapsedSpanMap[spanID] = struct{}{}
-				}
-			}
+			_, spansFromRootToNode := getPathFromRootToSelectedSpanId(rootNode, selectedSpanID, updatedUncollapsedSpans, isSelectedSpanIDUnCollapsed)
+			updatedUncollapsedSpans = append(updatedUncollapsedSpans, spansFromRootToNode...)
 
 			opts := traverseOpts{
-				uncollapsedSpans: uncollapsedSpanMap,
+				uncollapsedSpans: updatedUncollapsedSpans,
 				selectedSpanID:   selectedSpanID,
 			}
 			_preOrderTraversal := traverseTrace(rootNode, opts, 0, true, false)
@@ -232,5 +223,5 @@ func GetSelectedSpans(uncollapsedSpans []string, selectedSpanID string, traceRoo
 		startIndex = 0
 	}
 
-	return preOrderTraversal[startIndex:endIndex], slices.Collect(maps.Keys(uncollapsedSpanMap)), rootServiceName, rootServiceEntryPoint
+	return preOrderTraversal[startIndex:endIndex], updatedUncollapsedSpans, rootServiceName, rootServiceEntryPoint
 }

pkg/types/querybuildertypes/querybuildertypesv5/functions.go

@@ -326,6 +326,10 @@ func funcAbsolute(result *TimeSeries) *TimeSeries {
 
 // funcRunningDiff returns the running difference of each point
 func funcRunningDiff(result *TimeSeries) *TimeSeries {
+	if len(result.Values) == 0 {
+		return result
+	}
+
 	// iterate over the points in reverse order
 	for idx := len(result.Values) - 1; idx >= 0; idx-- {
 		if idx > 0 {

pkg/types/querybuildertypes/querybuildertypesv5/functions_test.go

@@ -291,6 +291,11 @@ func TestFuncRunningDiff(t *testing.T) {
 		values []float64
 		want   []float64
 	}{
+		{
+			name:   "test funcRunningDiff with empty series",
+			values: []float64{},
+			want:   []float64{},
+		},
 		{
 			name:   "test funcRunningDiff",
 			values: []float64{1, 2, 3},