improve error reporting

bytecode.go

@@ -102,10 +102,7 @@ func (s *State) LoadBytecode(bytecode []byte, name string) error {
 	)
 
 	if status != 0 {
-		err := &LuaError{
+		err := s.CreateLuaError(int(status), fmt.Sprintf("LoadBytecode(%s)", name))
-			Code:    int(status),
-			Message: s.ToString(-1),
-		}
 		s.Pop(1) // Remove error message
 		return err
 	}
@@ -123,10 +120,7 @@ func (s *State) RunBytecode() error {
 func (s *State) RunBytecodeWithResults(nresults int) error {
 	status := C.lua_pcall(s.L, 0, C.int(nresults), 0)
 	if status != 0 {
-		err := &LuaError{
+		err := s.CreateLuaError(int(status), fmt.Sprintf("RunBytecode(nresults=%d)", nresults))
-			Code:    int(status),
-			Message: s.ToString(-1),
-		}
 		s.Pop(1) // Remove error message
 		return err
 	}
@@ -152,10 +146,7 @@ func (s *State) LoadAndRunBytecode(bytecode []byte, name string) error {
 	)
 
 	if status != 0 {
-		err := &LuaError{
+		err := s.CreateLuaError(int(status), fmt.Sprintf("LoadAndRunBytecode(%s)", name))
-			Code:    int(status),
-			Message: s.ToString(-1),
-		}
 		s.Pop(1) // Remove error message
 		return err
 	}
@@ -182,10 +173,7 @@ func (s *State) LoadAndRunBytecodeWithResults(bytecode []byte, name string, nres
 	)
 
 	if status != 0 {
-		err := &LuaError{
+		err := s.CreateLuaError(int(status), fmt.Sprintf("LoadAndRunBytecodeWithResults(%s, nresults=%d)", name, nresults))
-			Code:    int(status),
-			Message: s.ToString(-1),
-		}
 		s.Pop(1) // Remove error message
 		return err
 	}

stack.go

@@ -5,16 +5,45 @@ package luajit
 #include <lauxlib.h>
 */
 import "C"
-import "fmt"
+import (
+	"fmt"
+	"strings"
+)
 
-// LuaError represents an error from the Lua state
+// LuaError represents an enhanced error from the Lua state
 type LuaError struct {
 	Code       int
 	Message    string
+	File       string
+	Line       int
+	StackTrace string
+	Context    string
 }
 
 func (e *LuaError) Error() string {
-	return fmt.Sprintf("lua error (code=%d): %s", e.Code, e.Message)
+	var parts []string
+
+	if e.File != "" && e.Line > 0 {
+		parts = append(parts, fmt.Sprintf("%s:%d", e.File, e.Line))
+	}
+
+	if e.Context != "" {
+		parts = append(parts, fmt.Sprintf("[%s]", e.Context))
+	}
+
+	parts = append(parts, e.Message)
+
+	if e.Code != 0 {
+		parts = append(parts, fmt.Sprintf("(code=%d)", e.Code))
+	}
+
+	result := strings.Join(parts, " ")
+
+	if e.StackTrace != "" {
+		result += "\n" + e.StackTrace
+	}
+
+	return result
 }
 
 // Stack management constants from lua.h
@@ -45,3 +74,50 @@ func (s *State) GetStackTrace() string {
 
 	return trace
 }
+
+// GetErrorInfo extracts detailed error information from the Lua stack
+func (s *State) GetErrorInfo(context string) *LuaError {
+	if s.GetTop() == 0 {
+		return &LuaError{
+			Message: "unknown error (empty stack)",
+			Context: context,
+		}
+	}
+
+	message := s.ToString(-1)
+
+	// Parse file:line from common Lua error format
+	var file string
+	var line int
+
+	if colonPos := strings.Index(message, ":"); colonPos > 0 {
+		beforeColon := message[:colonPos]
+		afterColon := message[colonPos+1:]
+
+		if secondColonPos := strings.Index(afterColon, ":"); secondColonPos > 0 {
+			file = beforeColon
+			if n, err := fmt.Sscanf(afterColon[:secondColonPos], "%d", &line); n == 1 && err == nil {
+				// Strip the file:line part from message for cleaner display
+				message = strings.TrimSpace(afterColon[secondColonPos+1:])
+			}
+		}
+	}
+
+	// Get stack trace
+	stackTrace := s.GetStackTrace()
+
+	return &LuaError{
+		Message:    message,
+		File:       file,
+		Line:       line,
+		StackTrace: stackTrace,
+		Context:    context,
+	}
+}
+
+// CreateLuaError creates a LuaError with full context information
+func (s *State) CreateLuaError(code int, context string) *LuaError {
+	err := s.GetErrorInfo(context)
+	err.Code = code
+	return err
+}

wrapper.go

@@ -342,10 +342,7 @@ func (s *State) LoadString(code string) error {
 
 	status := C.luaL_loadstring(s.L, ccode)
 	if status != 0 {
-		err := &LuaError{
+		err := s.CreateLuaError(int(status), "LoadString")
-			Code:    int(status),
-			Message: s.ToString(-1),
-		}
 		s.Pop(1) // Remove error message
 		return err
 	}
@@ -359,10 +356,7 @@ func (s *State) LoadFile(filename string) error {
 
 	status := C.luaL_loadfile(s.L, cfilename)
 	if status != 0 {
-		err := &LuaError{
+		err := s.CreateLuaError(int(status), fmt.Sprintf("LoadFile(%s)", filename))
-			Code:    int(status),
-			Message: s.ToString(-1),
-		}
 		s.Pop(1) // Remove error message
 		return err
 	}
@@ -373,10 +367,7 @@ func (s *State) LoadFile(filename string) error {
 func (s *State) Call(nargs, nresults int) error {
 	status := C.lua_pcall(s.L, C.int(nargs), C.int(nresults), 0)
 	if status != 0 {
-		err := &LuaError{
+		err := s.CreateLuaError(int(status), fmt.Sprintf("Call(%d,%d)", nargs, nresults))
-			Code:    int(status),
-			Message: s.ToString(-1),
-		}
 		s.Pop(1) // Remove error message
 		return err
 	}
@@ -390,10 +381,7 @@ func (s *State) DoString(code string) error {
 
 	status := C.do_string(s.L, ccode)
 	if status != 0 {
-		err := &LuaError{
+		err := s.CreateLuaError(int(status), "DoString")
-			Code:    int(status),
-			Message: s.ToString(-1),
-		}
 		s.Pop(1) // Remove error message
 		return err
 	}
@@ -407,10 +395,7 @@ func (s *State) DoFile(filename string) error {
 
 	status := C.do_file(s.L, cfilename)
 	if status != 0 {
-		err := &LuaError{
+		err := s.CreateLuaError(int(status), fmt.Sprintf("DoFile(%s)", filename))
-			Code:    int(status),
-			Message: s.ToString(-1),
-		}
 		s.Pop(1) // Remove error message
 		return err
 	}
@@ -426,10 +411,7 @@ func (s *State) Execute(code string) (int, error) {
 
 	status := C.execute_with_results(s.L, ccode, 1) // store_results=true
 	if status != 0 {
-		err := &LuaError{
+		err := s.CreateLuaError(int(status), "Execute")
-			Code:    int(status),
-			Message: s.ToString(-1),
-		}
 		s.Pop(1) // Remove error message
 		return 0, err
 	}