Add IsPathInTree function

Add check function `IsPathInTree` to verify whether the provided path is
in the given YAML structure.

assets/examples/types.yml

@@ -27,21 +27,36 @@ yaml:
 
   named-entry-list-using-name:
   - name: A
+    foo: bar
   - name: B
+    foo: bar
   - name: C
+    foo: bar
   - name: X
+    foo: bar
   - name: Z
+    foo: bar
 
   named-entry-list-using-key:
   - key: A
+    foo: bar
   - key: B
+    foo: bar
   - key: C
+    foo: bar
   - key: X
+    foo: bar
   - key: Z
+    foo: bar
 
   named-entry-list-using-id:
   - id: A
+    foo: bar
   - id: B
+    foo: bar
   - id: C
+    foo: bar
   - id: X
+    foo: bar
   - id: Z
+    foo: bar

getting_test.go

@@ -35,11 +35,11 @@ var _ = Describe("getting stuff test cases", func() {
 			Expect(grab(example, "/yaml/map/intA")).To(BeEquivalentTo(42))
 			Expect(grab(example, "/yaml/map/mapA")).To(BeAsNode(yml(`{ key0: A, key1: A }`)))
 			Expect(grab(example, "/yaml/map/listA")).To(BeAsNode(list(`[ A, A, A ]`)))
-			Expect(grab(example, "/yaml/named-entry-list-using-name/name=B")).To(BeAsNode(yml(`{ name: B }`)))
-			Expect(grab(example, "/yaml/named-entry-list-using-key/key=B")).To(BeAsNode(yml(`{ key: B }`)))
-			Expect(grab(example, "/yaml/named-entry-list-using-id/id=B")).To(BeAsNode(yml(`{ id: B }`)))
+			Expect(grab(example, "/yaml/named-entry-list-using-name/name=B")).To(BeAsNode(yml(`{ name: B, foo: bar }`)))
+			Expect(grab(example, "/yaml/named-entry-list-using-key/key=B")).To(BeAsNode(yml(`{ key: B, foo: bar }`)))
+			Expect(grab(example, "/yaml/named-entry-list-using-id/id=B")).To(BeAsNode(yml(`{ id: B, foo: bar }`)))
 			Expect(grab(example, "/yaml/simple-list/1")).To(BeEquivalentTo("B"))
-			Expect(grab(example, "/yaml/named-entry-list-using-key/3")).To(BeAsNode(yml(`{ key: X }`)))
+			Expect(grab(example, "/yaml/named-entry-list-using-key/3")).To(BeAsNode(yml(`{ key: X, foo: bar }`)))
 
 			example = yml(assets("bosh-yaml", "manifest.yml"))
 			Expect(grab(example, "/instance_groups/name=web/networks/name=concourse/static_ips/0")).To(BeEquivalentTo("XX.XX.XX.XX"))

path.go

@@ -229,6 +229,30 @@ func ListPaths(location string, style PathStyle) ([]Path, error) {
 	return paths, nil
 }
 
+// IsPathInTree returns whether the provided path is in the given YAML structure
+func IsPathInTree(tree *yamlv3.Node, pathString string) (bool, error) {
+	searchPath, err := ParsePathString(pathString, tree)
+	if err != nil {
+		return false, err
+	}
+
+	resultChan := make(chan bool)
+
+	go func() {
+		for _, node := range tree.Content {
+			traverseTree(Path{}, node, func(path Path, _ *yamlv3.Node) {
+				if path.ToGoPatchStyle() == searchPath.ToGoPatchStyle() {
+					resultChan <- true
+				}
+			})
+
+			resultChan <- false
+		}
+	}()
+
+	return <-resultChan, nil
+}
+
 func traverseTree(path Path, node *yamlv3.Node, leafFunc func(p Path, n *yamlv3.Node)) {
 	switch node.Kind {
 	case yamlv3.DocumentNode:

path_test.go

@@ -204,4 +204,19 @@ var _ = Describe("path tests", func() {
 			Expect(list).To(BeEquivalentTo(listOfPathsWithSameValue))
 		})
 	})
+
+	Context("checking for path in YAML", func() {
+		It("should check whether the provided path is in the YAML", func() {
+			example := yml(assets("examples", "types.yml"))
+
+			Expect(IsPathInTree(example, "/yaml/map/before")).To(BeTrue())
+			Expect(IsPathInTree(example, "/yaml/map/nope")).To(BeFalse())
+
+			Expect(IsPathInTree(example, "/yaml/simple-list/0")).To(BeTrue())
+			Expect(IsPathInTree(example, "/yaml/simple-list/5")).To(BeFalse())
+
+			Expect(IsPathInTree(example, "/yaml/named-entry-list-using-name/name=A/foo")).To(BeTrue())
+			Expect(IsPathInTree(example, "/yaml/named-entry-list-using-name/name=nope/foo")).To(BeFalse())
+		})
+	})
 })