Fixed bug where jsonpath expression with a nested range does not process subsequent nodes

Author: brianpursley

staging/src/k8s.io/client-go/util/jsonpath/jsonpath.go

@@ -29,12 +29,12 @@ import (
 type JSONPath struct {
 	name       string
 	parser     *Parser
-	stack      [][]reflect.Value // push and pop values in different scopes
-	cur        []reflect.Value   // current scope values
 	beginRange int
 	inRange    int
 	endRange   int
 
+	lastEndNode *Node
+
 	allowMissingKeys bool
 }
 
@@ -81,37 +81,44 @@ func (j *JSONPath) FindResults(data interface{}) ([][]reflect.Value, error) {
 		return nil, fmt.Errorf("%s is an incomplete jsonpath template", j.name)
 	}
 
-	j.cur = []reflect.Value{reflect.ValueOf(data)}
+	cur := []reflect.Value{reflect.ValueOf(data)}
 	nodes := j.parser.Root.Nodes
 	fullResult := [][]reflect.Value{}
 	for i := 0; i < len(nodes); i++ {
 		node := nodes[i]
-		results, err := j.walk(j.cur, node)
+		results, err := j.walk(cur, node)
 		if err != nil {
 			return nil, err
 		}
 
 		// encounter an end node, break the current block
 		if j.endRange > 0 && j.endRange <= j.inRange {
 			j.endRange--
+			j.lastEndNode = &nodes[i]
 			break
 		}
 		// encounter a range node, start a range loop
 		if j.beginRange > 0 {
 			j.beginRange--
 			j.inRange++
-			for k, value := range results {
+			for _, value := range results {
 				j.parser.Root.Nodes = nodes[i+1:]
-				if k == len(results)-1 {
-					j.inRange--
-				}
 				nextResults, err := j.FindResults(value.Interface())
 				if err != nil {
 					return nil, err
 				}
 				fullResult = append(fullResult, nextResults...)
 			}
-			break
+			j.inRange--
+
+			// Fast forward to resume processing after the most recent end node that was encountered
+			for k := i + 1; k < len(nodes); k++ {
+				if &nodes[k] == j.lastEndNode {
+					i = k
+					break
+				}
+			}
+			continue
 		}
 		fullResult = append(fullResult, results)
 	}
@@ -212,17 +219,11 @@ func (j *JSONPath) evalIdentifier(input []reflect.Value, node *IdentifierNode) (
 	results := []reflect.Value{}
 	switch node.Name {
 	case "range":
-		j.stack = append(j.stack, j.cur)
 		j.beginRange++
 		results = input
 	case "end":
-		if j.endRange < j.inRange { // inside a loop, break the current block
+		if j.inRange > 0 {
 			j.endRange++
-			break
-		}
-		// the loop is about to end, pop value and continue the following execution
-		if len(j.stack) > 0 {
-			j.cur, j.stack = j.stack[len(j.stack)-1], j.stack[:len(j.stack)-1]
 		} else {
 			return results, fmt.Errorf("not in range, nothing to end")
 		}

staging/src/k8s.io/client-go/util/jsonpath/jsonpath_test.go

@@ -298,6 +298,133 @@ func TestKubernetes(t *testing.T) {
 	testJSONPathSortOutput(randomPrintOrderTests, t)
 }
 
+func TestNestedRanges(t *testing.T) {
+	var input = []byte(`{
+		"items": [
+			{
+				"metadata": {
+					"name": "pod1"
+				},
+				"spec": {
+					"containers": [
+						{
+							"name": "foo",
+							"another": [
+								{ "name": "value1" },
+								{ "name": "value2" }
+							]
+						},
+						{
+							"name": "bar",
+							"another": [
+								{ "name": "value1" },
+								{ "name": "value2" }
+							]
+						}
+					]
+                }
+			},
+			{
+				"metadata": {
+					"name": "pod2"
+				},
+				"spec": {
+					"containers": [
+						{
+							"name": "baz",
+							"another": [
+								{ "name": "value1" },
+								{ "name": "value2" }
+							]
+						}
+					]
+                }
+			}
+		]
+	}`)
+	var data interface{}
+	err := json.Unmarshal(input, &data)
+	if err != nil {
+		t.Error(err)
+	}
+
+	testJSONPath(
+		[]jsonpathTest{
+			{
+				"nested range with a trailing newline",
+				`{range .items[*]}` +
+					`{.metadata.name}` +
+					`{":"}` +
+					`{range @.spec.containers[*]}` +
+					`{.name}` +
+					`{","}` +
+					`{end}` +
+					`{"+"}` +
+					`{end}`,
+				data,
+				"pod1:foo,bar,+pod2:baz,+",
+				false,
+			},
+		},
+		false,
+		t,
+	)
+
+	testJSONPath(
+		[]jsonpathTest{
+			{
+				"nested range with a trailing character within another nested range with a trailing newline",
+				`{range .items[*]}` +
+					`{.metadata.name}` +
+					`{"~"}` +
+					`{range @.spec.containers[*]}` +
+					`{.name}` +
+					`{":"}` +
+					`{range @.another[*]}` +
+					`{.name}` +
+					`{","}` +
+					`{end}` +
+					`{"+"}` +
+					`{end}` +
+					`{"#"}` +
+					`{end}`,
+				data,
+				"pod1~foo:value1,value2,+bar:value1,value2,+#pod2~baz:value1,value2,+#",
+				false,
+			},
+		},
+		false,
+		t,
+	)
+
+	testJSONPath(
+		[]jsonpathTest{
+			{
+				"two nested ranges at the same level with a trailing newline",
+				`{range .items[*]}` +
+					`{.metadata.name}` +
+					`{"\t"}` +
+					`{range @.spec.containers[*]}` +
+					`{.name}` +
+					`{" "}` +
+					`{end}` +
+					`{"\t"}` +
+					`{range @.spec.containers[*]}` +
+					`{.name}` +
+					`{" "}` +
+					`{end}` +
+					`{"\n"}` +
+					`{end}`,
+				data,
+				"pod1\tfoo bar \tfoo bar \npod2\tbaz \tbaz \n",
+				false,
+			},
+		},
+		false,
+		t,
+	)
+}
+
 func TestFilterPartialMatchesSometimesMissingAnnotations(t *testing.T) {
 	// for https://issues.k8s.io/45546
 	var input = []byte(`{