refactor: expandPathPatterns fn don't mutate input

internal/descriptor/registry.go

@@ -164,7 +164,7 @@ type Registry struct {
 	// enableRpcDeprecation whether to process grpc method's deprecated option
 	enableRpcDeprecation bool
 
-	// expandSlashedPathPatterns, if true, for a path parameter carying a sub-path, described via parameter pattern (i.e.
+	// expandSlashedPathPatterns, if true, for a path parameter carrying a sub-path, described via parameter pattern (i.e.
 	// the pattern contains forward slashes), this will expand the _pattern_ into the URI and will _replace_ the parameter
 	// with new path parameters inferred from patterns wildcards.
 	//

protoc-gen-openapiv2/internal/genopenapi/template.go

@@ -1156,19 +1156,19 @@ func renderServiceTags(services []*descriptor.Service, reg *descriptor.Registry)
 	return tags
 }
 
-// expandPathPatterns search the URI parts for path parameters with pattern and when the pattern contains a sub-path,
+// expandPathPatterns searches the URI parts for path parameters with pattern and when the pattern contains a sub-path,
 // it expands the pattern into the URI parts and adds the new path parameters to the pathParams slice.
 //
 // Parameters:
 //   - pathParts:	the URI parts parsed from the path template with `templateToParts` function
-//   - pathParams: the path parameters of the service binding, this slice will be mutated when the path pattern contains
-//     a sub-path with wildcard.
+//   - pathParams: the path parameters of the service binding
 //
 // Returns:
 //
-//	The modified pathParts. Also mutates the pathParams slice.
-func expandPathPatterns(pathParts []string, pathParams *[]descriptor.Parameter) []string {
+//	The modified pathParts and pathParams slice.
+func expandPathPatterns(pathParts []string, pathParams []descriptor.Parameter) ([]string, []descriptor.Parameter) {
 	expandedPathParts := []string{}
+	modifiedPathParams := pathParams
 	for _, pathPart := range pathParts {
 		if !strings.HasPrefix(pathPart, "{") || !strings.HasSuffix(pathPart, "}") {
 			expandedPathParts = append(expandedPathParts, pathPart)
@@ -1186,13 +1186,13 @@ func expandPathPatterns(pathParts []string, pathParams *[]descriptor.Parameter)
 			expandedPathParts = append(expandedPathParts, pathPart)
 			continue
 		}
-		pathParamIndex := slices.IndexFunc(*pathParams, func(p descriptor.Parameter) bool {
+		pathParamIndex := slices.IndexFunc(modifiedPathParams, func(p descriptor.Parameter) bool {
 			return p.FieldPath.String() == paramName
 		})
 		if pathParamIndex == -1 {
 			panic(fmt.Sprintf("Path parameter %q not found in path parameters", paramName))
 		}
-		pathParam := (*pathParams)[pathParamIndex]
+		pathParam := modifiedPathParams[pathParamIndex]
 		patternParts := strings.Split(pattern, "/")
 		for _, patternPart := range patternParts {
 			if patternPart != "*" {
@@ -1217,15 +1217,15 @@ func expandPathPatterns(pathParts []string, pathParams *[]descriptor.Parameter)
 				}},
 				Method: nil,
 			}
-			*pathParams = append((*pathParams), newParam)
+			modifiedPathParams = append(modifiedPathParams, newParam)
 			if pathParamIndex != -1 {
 				// the new parameter from the pattern replaces the old path parameter
-				*pathParams = append((*pathParams)[:pathParamIndex], (*pathParams)[pathParamIndex+1:]...)
+				modifiedPathParams = append(modifiedPathParams[:pathParamIndex], modifiedPathParams[pathParamIndex+1:]...)
 				pathParamIndex = -1
 			}
 		}
 	}
-	return expandedPathParts
+	return expandedPathParts, modifiedPathParams
 }
 
 func renderServices(services []*descriptor.Service, paths *openapiPathsObject, reg *descriptor.Registry, requestResponseRefs, customRefs refMap, msgs []*descriptor.Message, defs openapiDefinitionsObject) error {
@@ -1253,11 +1253,11 @@ func renderServices(services []*descriptor.Service, paths *openapiPathsObject, r
 				operationFunc := operationForMethod(b.HTTPMethod)
 				// Iterate over all the OpenAPI parameters
 				parameters := openapiParametersObject{}
-				pathParams := b.PathParams
 				// split the path template into its parts
 				parts := templateToParts(b.PathTmpl.Template, reg, meth.RequestType.Fields, msgs)
+				pathParams := b.PathParams
 				if reg.GetExpandSlashedPathPatterns() {
-					parts = expandPathPatterns(parts, &pathParams)
+					parts, pathParams = expandPathPatterns(parts, pathParams)
 				}
 				// extract any constraints specified in the path placeholders into ECMA regular expressions
 				pathParamRegexpMap := partsToRegexpMap(parts)

protoc-gen-openapiv2/internal/genopenapi/template_test.go

@@ -4159,12 +4159,12 @@ func TestTemplateToOpenAPIPathExpandSlashed(t *testing.T) {
 	reg.SetExpandSlashedPathPatterns(true)
 	for _, data := range tests {
 		reg.SetUseJSONNamesForFields(data.useJSONNames)
-		actual := templateToExpandedPath(data.input, reg, generateFieldsForJSONReservedName(), generateMsgsForJSONReservedName(), &data.pathParams)
-		if data.expected != actual {
-			t.Errorf("Expected templateToOpenAPIPath(%v) = %v, actual: %v", data.input, data.expected, actual)
+		actualParts, actualParams := templateToExpandedPath(data.input, reg, generateFieldsForJSONReservedName(), generateMsgsForJSONReservedName(), data.pathParams)
+		if data.expected != actualParts {
+			t.Errorf("Expected templateToOpenAPIPath(%v) = %v, actual: %v", data.input, data.expected, actualParts)
 		}
 		pathParamsNames := make([]string, 0)
-		for _, param := range data.pathParams {
+		for _, param := range actualParams {
 			pathParamsNames = append(pathParamsNames, param.FieldPath[0].Name)
 		}
 		if !reflect.DeepEqual(data.expectedPathParams, pathParamsNames) {
@@ -4287,8 +4287,9 @@ func templateToRegexpMap(path string, reg *descriptor.Registry, fields []*descri
 	return partsToRegexpMap(templateToParts(path, reg, fields, msgs))
 }
 
-func templateToExpandedPath(path string, reg *descriptor.Registry, fields []*descriptor.Field, msgs []*descriptor.Message, pathParams *[]descriptor.Parameter) string {
-	return partsToOpenAPIPath(expandPathPatterns(templateToParts(path, reg, fields, msgs), pathParams), make(map[string]string))
+func templateToExpandedPath(path string, reg *descriptor.Registry, fields []*descriptor.Field, msgs []*descriptor.Message, pathParams []descriptor.Parameter) (string, []descriptor.Parameter) {
+	pathParts, pathParams := expandPathPatterns(templateToParts(path, reg, fields, msgs), pathParams)
+	return partsToOpenAPIPath(pathParts, make(map[string]string)), pathParams
 }
 
 func TestFQMNToRegexpMap(t *testing.T) {