chore: Improve sortables detection (#1151)

Co-authored-by: chavacava <salvador.cavadini@gmail.com>

internal/astutils/ast_utils.go

@@ -0,0 +1,60 @@
+package astutils
+
+import "go/ast"
+
+// FuncSignatureIs returns true if the given func decl satisfies a signature characterized
+// by the given name, parameters types and return types; false otherwise.
+//
+// Example: to check if a function declaration has the signature Foo(int, string) (bool,error)
+// call to FuncSignatureIs(funcDecl,"Foo",[]string{"int","string"},[]string{"bool","error"})
+func FuncSignatureIs(funcDecl *ast.FuncDecl, wantName string, wantParametersTypes, wantResultsTypes []string) bool {
+	if wantName != funcDecl.Name.String() {
+		return false // func name doesn't match expected one
+	}
+
+	funcParametersTypes := getTypeNames(funcDecl.Type.Params)
+	if len(wantParametersTypes) != len(funcParametersTypes) {
+		return false // func has not the expected number of parameters
+	}
+
+	funcResultsTypes := getTypeNames(funcDecl.Type.Results)
+	if len(wantResultsTypes) != len(funcResultsTypes) {
+		return false // func has not the expected number of return values
+	}
+
+	for i, wantType := range wantParametersTypes {
+		if wantType != funcParametersTypes[i] {
+			return false // type of a func's parameter does not match the type of the corresponding expected parameter
+		}
+	}
+
+	for i, wantType := range wantResultsTypes {
+		if wantType != funcResultsTypes[i] {
+			return false // type of a func's return value does not match the type of the corresponding expected return value
+		}
+	}
+
+	return true
+}
+
+func getTypeNames(fields *ast.FieldList) []string {
+	result := []string{}
+
+	if fields == nil {
+		return result
+	}
+
+	for _, field := range fields.List {
+		typeName := field.Type.(*ast.Ident).Name
+		if field.Names == nil { // unnamed field
+			result = append(result, typeName)
+			continue
+		}
+
+		for range field.Names { // add one type name for each field name
+			result = append(result, typeName)
+		}
+	}
+
+	return result
+}