chore: make wasm work

datamodel/low/base/schema.go

@@ -162,6 +162,10 @@ func (s *Schema) GetContext() context.Context {
 // Hash will calculate a SHA256 hash from the values of the schema, This allows equality checking against
 // Schemas defined inside an OpenAPI document. The only way to know if a schema has changed, is to hash it.
 func (s *Schema) Hash() [32]byte {
+	// a nil schema (e.g. from a SchemaProxy that failed to resolve) hashes like an empty one.
+	if s == nil {
+		return sha256.Sum256([]byte{})
+	}
 	// calculate a hash from every property in the schema.
 	var d []string
 	if !s.SchemaTypeRef.IsEmpty() {

datamodel/low/base/schema_test.go

@@ -1970,3 +1970,11 @@ func TestExtractSchema_CheckExampleNodesExtracted(t *testing.T) {
 		t.Fail()
 	}
 }
+
+func TestSchema_Hash_NilReceiver(t *testing.T) {
+	// a nil schema (e.g. from a SchemaProxy that failed to resolve) must not panic
+	// and hashes like an empty schema.
+	var s *Schema
+	empty := &Schema{}
+	assert.Equal(t, empty.Hash(), s.Hash())
+}

datamodel/low/v3/create_document.go

@@ -57,7 +57,7 @@ func createDocument(info *datamodel.SpecInfo, config *datamodel.DocumentConfigur
 	doc.Rolodex = rolodex
 
 	// If basePath is provided, add a local filesystem to the rolodex.
-	if idxConfig.BasePath != "" || config.AllowFileReferences {
+	if idxConfig.BasePath != "" && config.AllowFileReferences {
 		var cwd string
 		cwd, _ = filepath.Abs(config.BasePath)
 		// if a supplied local filesystem is provided, add it to the rolodex.

index/rolodex.go

@@ -357,7 +357,7 @@ func (r *Rolodex) IndexTheRolodex() error {
 		// which does not exist, but is used to formulate the absolute path to root references correctly.
 		if r.indexConfig.BasePath != "" && r.indexConfig.BaseURL == nil {
 			basePath := r.indexConfig.BasePath
-			if !filepath.IsAbs(basePath) {
+			if !filepath.IsAbs(basePath) && r.indexConfig.AllowFileLookup {
 				basePath, _ = filepath.Abs(basePath)
 			}
 

what-changed/model/schema.go

@@ -304,6 +304,15 @@ func (s *SchemaChanges) TotalBreakingChanges() int {
 	return t
 }
 
+// schemasProvablyEqual checks that both proxies resolve and hash identically. If either proxy
+// cannot be resolved (e.g. an unresolvable circular reference), equality cannot be proven, so a
+// change should be reported instead of hashing a nil schema.
+func schemasProvablyEqual(l, r *base.SchemaProxy) bool {
+	lSchema := l.Schema()
+	rSchema := r.Schema()
+	return lSchema != nil && rSchema != nil && lSchema.Hash() == rSchema.Hash()
+}
+
 // CompareSchemas accepts a left and right SchemaProxy and checks for changes. If anything is found, returns
 // a pointer to SchemaChanges, otherwise returns nil
 func CompareSchemas(l, r *base.SchemaProxy) *SchemaChanges {
@@ -346,11 +355,13 @@ func CompareSchemas(l, r *base.SchemaProxy) *SchemaChanges {
 		if !l.IsReference() && r.IsReference() {
 			// check if the referenced schema matches or not
 			// https://github.com/pb33f/libopenapi/issues/218
-			lHash := l.Schema().Hash()
-			rHash := r.Schema().Hash()
-			if lHash != rHash {
+			if !schemasProvablyEqual(l, r) {
+				var rContentNode *yaml.Node = r.GetValueNode()
+				if len(r.GetValueNode().Content) > 1 {
+					rContentNode = r.GetValueNode().Content[1]
+				}
 				CreateChange(&changes, Modified, v3.RefLabel,
-					l.GetValueNode(), r.GetValueNode().Content[1], true, l, r.GetReference())
+					l.GetValueNode(), rContentNode, true, l, r.GetReference())
 				sc.PropertyChanges = NewPropertyChanges(changes)
 				return sc // we're done here
 			}
@@ -360,11 +371,13 @@ func CompareSchemas(l, r *base.SchemaProxy) *SchemaChanges {
 		if l.IsReference() && !r.IsReference() {
 			// check if the referenced schema matches or not
 			// https://github.com/pb33f/libopenapi/issues/218
-			lHash := l.Schema().Hash()
-			rHash := r.Schema().Hash()
-			if lHash != rHash {
+			if !schemasProvablyEqual(l, r) {
+				var lContentNode *yaml.Node = l.GetValueNode()
+				if len(l.GetValueNode().Content) > 1 {
+					lContentNode = l.GetValueNode().Content[1]
+				}
 				CreateChange(&changes, Modified, v3.RefLabel,
-					l.GetValueNode().Content[1], r.GetValueNode(), true, l.GetReference(), r)
+					lContentNode, r.GetValueNode(), true, l.GetReference(), r)
 				sc.PropertyChanges = NewPropertyChanges(changes)
 				return sc // done, nothing else to do.
 			}
@@ -373,6 +386,18 @@ func CompareSchemas(l, r *base.SchemaProxy) *SchemaChanges {
 		lSchema := l.Schema()
 		rSchema := r.Schema()
 
+		// if either proxy cannot be resolved (e.g. an unresolvable circular reference),
+		// the schemas cannot be walked. Report a modification if only one side is nil.
+		if lSchema == nil || rSchema == nil {
+			if lSchema != rSchema {
+				CreateChange(&changes, Modified, v3.SchemaLabel,
+					l.GetValueNode(), r.GetValueNode(), true, l, r)
+				sc.PropertyChanges = NewPropertyChanges(changes)
+				return sc
+			}
+			return nil
+		}
+
 		if low.AreEqual(lSchema, rSchema) {
 			// there is no point going on, we know nothing changed!
 			return nil

what-changed/model/schema_test.go

@@ -3232,3 +3232,67 @@ components:
 	assert.Equal(t, 1, changes.TotalChanges())
 
 }
+
+func TestCompareSchemas_UnresolvableCircularAliasRef(t *testing.T) {
+	// a property that changes between an inline schema and a $ref pointing at a
+	// ref-to-ref alias chain inside a reference cycle. The alias chain cannot be
+	// resolved by the proxy (circular lookup), so SchemaProxy.Schema() returns nil;
+	// comparing must report a change, not panic hashing a nil schema.
+	inline := `openapi: 3.1.0
+components:
+  schemas:
+    VendorCredentialSummary:
+      $ref: "#/components/schemas/VendorCredentialFile"
+    VendorCredentialFile:
+      $ref: "#/components/schemas/VendorCredentialFileImpl"
+    VendorCredentialFileImpl:
+      type: object
+      properties:
+        summary:
+          $ref: "#/components/schemas/VendorCredentialSummary"
+    VendorCredentialDataRequest:
+      type: object
+      properties:
+        summary:
+          allOf:
+            - type: object
+              additionalProperties: true
+`
+
+	ref := `openapi: 3.1.0
+components:
+  schemas:
+    VendorCredentialSummary:
+      $ref: "#/components/schemas/VendorCredentialFile"
+    VendorCredentialFile:
+      $ref: "#/components/schemas/VendorCredentialFileImpl"
+    VendorCredentialFileImpl:
+      type: object
+      properties:
+        summary:
+          $ref: "#/components/schemas/VendorCredentialSummary"
+    VendorCredentialDataRequest:
+      type: object
+      properties:
+        summary:
+          $ref: "#/components/schemas/VendorCredentialSummary"
+`
+
+	leftDoc, rightDoc := test_BuildDoc(inline, ref)
+
+	// inline -> ref
+	lSchemaProxy := leftDoc.Components.Value.FindSchema("VendorCredentialDataRequest").Value
+	rSchemaProxy := rightDoc.Components.Value.FindSchema("VendorCredentialDataRequest").Value
+	changes := CompareSchemas(lSchemaProxy, rSchemaProxy)
+	assert.NotNil(t, changes)
+	assert.Equal(t, 1, changes.TotalChanges())
+	assert.Equal(t, Modified, changes.GetAllChanges()[0].ChangeType)
+	assert.Equal(t, v3.RefLabel, changes.GetAllChanges()[0].Property)
+
+	// ref -> inline
+	changes = CompareSchemas(rSchemaProxy, lSchemaProxy)
+	assert.NotNil(t, changes)
+	assert.Equal(t, 1, changes.TotalChanges())
+	assert.Equal(t, Modified, changes.GetAllChanges()[0].ChangeType)
+	assert.Equal(t, v3.RefLabel, changes.GetAllChanges()[0].Property)
+}