fix: handle example comparison correctly. #61

examples can be anything, most commonly maps. previously `libopenapi` did not check maps correctly. Now it does. It was also creating a panic by inserting a nil pointer as the value to a map key. This has also been fixed.

Examples are the only element that use this pattern for comparison.

what-changed/model/change_types.go

@@ -113,14 +113,6 @@ func NewPropertyChanges(changes []*Change) *PropertyChanges {
     return &PropertyChanges{Changes: changes}
 }
 
-// SortByChangeType will order changes by the types of change they represent,
-// This is a destructive action and will permanently re-order Changes.
-//func (p PropertyChanges[T]) SortByChangeType() {
-//	sort.SliceStable(p.Changes, func(i, j int) bool {
-//		return p.Changes[i].ChangeType < p.Changes[j].ChangeType
-//	})
-//}
-
 // PropertyCheck is used by functions to check the state of left and right values.
 type PropertyCheck struct {
 

what-changed/model/comparison_functions.go

@@ -5,6 +5,7 @@ package model
 
 import (
 	"fmt"
+	"reflect"
 	"strings"
 	"sync"
 
@@ -250,7 +251,12 @@ func CheckMapForChangesWithComp[T any, R any](expLeft, expRight map[low.KeyRefer
 		// run comparison.
 		if compare {
 			chLock.Lock()
-			expChanges[k] = compareFunc(p[k].Value, h[k].Value)
+			ch := compareFunc(p[k].Value, h[k].Value)
+			// incorrect map results were being generated causing panics.
+			// https://github.com/pb33f/libopenapi/issues/61
+			if !reflect.ValueOf(&ch).Elem().IsZero() {
+				expChanges[k] = ch
+			}
 			chLock.Unlock()
 		}
 		doneChan <- true

what-changed/model/document_test.go

@@ -1074,3 +1074,86 @@ webhooks:
 	assert.Equal(t, 2, extChanges.TotalChanges())
 	assert.Equal(t, 0, extChanges.TotalBreakingChanges())
 }
+
+func TestCompareDocuments_OpenAPIExampleMapChanges(t *testing.T) {
+	left := `openapi: 3.0.0
+paths:
+  /:
+    post:
+      requestBody:
+        content:
+          application/json:
+            examples:
+              test:
+                value:
+                  map:
+                    deep:
+                      date: 2020-01-01`
+
+	right := `openapi: 3.0.0
+paths:
+  /:
+    post:
+      requestBody:
+        content:
+          application/json:
+            examples:
+              test:
+                value:
+                  map:
+                    deep:
+                      date: "2020-01-04"`
+
+	// have to build docs fully to get access to objects
+	siLeft, _ := datamodel.ExtractSpecInfo([]byte(left))
+	siRight, _ := datamodel.ExtractSpecInfo([]byte(right))
+
+	lDoc, _ := v3.CreateDocument(siLeft)
+	rDoc, _ := v3.CreateDocument(siRight)
+
+	// compare.
+	extChanges := CompareDocuments(lDoc, rDoc)
+	assert.Equal(t, 1, extChanges.TotalChanges())
+	assert.Equal(t, 0, extChanges.TotalBreakingChanges())
+}
+
+func TestCompareDocuments_OpenAPIExampleNoExampleMapChanges(t *testing.T) {
+	left := `openapi: 3.0.0
+paths:
+  /:
+    post:
+      requestBody:
+        content:
+          application/json:
+            examples:
+              test:
+                value:
+                  map:
+                    deep:
+                      date: 2020-01-01`
+
+	right := `openapi: 3.0.0
+paths:
+  /:
+    post:
+      requestBody:
+        content:
+          application/json:
+            examples:
+              test:
+                value:
+                  map:
+                    deep:
+                      date: 2020-01-01`
+
+	// have to build docs fully to get access to objects
+	siLeft, _ := datamodel.ExtractSpecInfo([]byte(left))
+	siRight, _ := datamodel.ExtractSpecInfo([]byte(right))
+
+	lDoc, _ := v3.CreateDocument(siLeft)
+	rDoc, _ := v3.CreateDocument(siRight)
+
+	// compare.
+	extChanges := CompareDocuments(lDoc, rDoc)
+	assert.Nil(t, extChanges)
+}

what-changed/model/example.go

@@ -4,6 +4,7 @@
 package model
 
 import (
+	"crypto/sha256"
 	"fmt"
 	"sort"
 
@@ -72,7 +73,17 @@ func CompareExamples(l, r *base.Example) *ExampleChanges {
 		z := 0
 		for k := range l.Value.ValueNode.Content {
 			if k%2 == 0 {
-				lKeys[z] = fmt.Sprintf("%v-%v-%v", l.Value.ValueNode.Content[k].Value, l.Value.ValueNode.Content[k+1].Tag, l.Value.ValueNode.Content[k+1].Value)
+				// if there is no value (value is another map or something else), render the node into yaml and hash it.
+				// https://github.com/pb33f/libopenapi/issues/61
+				val := l.Value.ValueNode.Content[k+1].Value
+				if val == "" {
+					yaml, _ := yaml.Marshal(l.Value.ValueNode.Content[k+1].Content)
+					val = fmt.Sprint(sha256.Sum256(yaml))
+				}
+				lKeys[z] = fmt.Sprintf("%v-%v-%v",
+					l.Value.ValueNode.Content[k].Value,
+					l.Value.ValueNode.Content[k+1].Tag,
+					fmt.Sprintf("%x", val))
 				z++
 			} else {
 				continue
@@ -81,7 +92,17 @@ func CompareExamples(l, r *base.Example) *ExampleChanges {
 		z = 0
 		for k := range r.Value.ValueNode.Content {
 			if k%2 == 0 {
-				rKeys[z] = fmt.Sprintf("%v-%v-%v", r.Value.ValueNode.Content[k].Value, r.Value.ValueNode.Content[k+1].Tag, r.Value.ValueNode.Content[k+1].Value)
+				// if there is no value (value is another map or something else), render the node into yaml and hash it.
+				// https://github.com/pb33f/libopenapi/issues/61
+				val := r.Value.ValueNode.Content[k+1].Value
+				if val == "" {
+					yaml, _ := yaml.Marshal(r.Value.ValueNode.Content[k+1].Content)
+					val = fmt.Sprint(sha256.Sum256(yaml))
+				}
+				rKeys[z] = fmt.Sprintf("%v-%v-%v",
+					r.Value.ValueNode.Content[k].Value,
+					r.Value.ValueNode.Content[k+1].Tag,
+					fmt.Sprintf("%x", val))
 				z++
 			} else {
 				continue