Merge pull request #3 from krakend/feature/parse-syntax-errors

Properly parse syntax errors

error.go

@@ -177,22 +177,26 @@ func newError(err error, h errSourceHandler) error {
 	switch err.(type) {
 	case *lua.ApiError:
 		e := err.(*lua.ApiError)
-		p := strings.Split(e.Object.String(), ":")
-		c := len(p)
-
 		var (
 			problem = -1
 			text    = e.Error()
 		)
 
-		if c > 1 {
-			if v, err := strconv.Atoi(p[1]); err == nil {
-				problem = v
+		if e.Type == lua.ApiErrorSyntax {
+			text, problem = parseSyntaxError(e.Object.String())
+		} else {
+			p := strings.Split(e.Object.String(), ":")
+			c := len(p)
+
+			if c > 1 {
+				if v, err := strconv.Atoi(p[1]); err == nil {
+					problem = v
+				}
 			}
-		}
 
-		if c > 2 {
-			text = strings.Trim(strings.Join(p[2:], ":"), " ")
+			if c > 2 {
+				text = strings.Trim(strings.Join(p[2:], ":"), " ")
+			}
 		}
 
 		return &Error{
@@ -205,6 +209,31 @@ func newError(err error, h errSourceHandler) error {
 	return err
 }
 
+func parseSyntaxError(errorText string) (string, int) {
+	var (
+		problem = -1
+		text    = errorText
+	)
+
+	if strings.Contains(errorText, " at EOF:") {
+		problem = 0
+		text = strings.TrimSpace(strings.Split(errorText, ":")[1]) + " at EOF"
+
+		return text, problem
+	}
+
+	parts := strings.Split(errorText, " near ")
+	if len(parts) == 2 {
+		text = strings.Join(strings.Fields(strings.TrimSuffix(parts[1], "\n")), " ")
+		where := strings.Split(strings.TrimSuffix(strings.ReplaceAll(parts[0], "<string> line:", ""), ")"), "(column:")
+		if v, err := strconv.Atoi(where[0]); err == nil {
+			problem = v
+		}
+
+	}
+	return text, problem
+}
+
 func highlight(s string) string {
 	var buf bytes.Buffer
 	if err := quick.Highlight(&buf, s, "lua", "terminal", "solarized-dark"); err != nil {

error_test.go

@@ -6,6 +6,58 @@ import (
 	"testing"
 )
 
+func TestErrorSourceSyntaxError(t *testing.T) {
+	tests := []struct {
+		name     string
+		src      string
+		expected string
+	}{
+		{
+			name:     "Inline",
+			src:      "local p = person.new('Steeve');lokal t = 'fail'",
+			expected: "Line 1: 't': parse error",
+		},
+		{
+			name:     "Parsing error",
+			src:      "local p = person.new('Steeve')\nlokal t = 'fail'",
+			expected: "Line 2: 't': parse error",
+		},
+		{
+			name:     "Bad token",
+			src:      "local p = person.new('Steeve')\nlocal t & 'fail'",
+			expected: "Line 2: '&': Invalid token",
+		},
+		{
+			name:     "Unterminated string",
+			src:      "local p = person.new('Steeve)\nlocal t = 'okay'",
+			expected: "Line 2: 'Steeve)': unterminated string",
+		},
+		{
+			name:     "End of file",
+			src:      "local p = person.new('Steeve')\nprint(p:email()",
+			expected: "Line 0: syntax error at EOF",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			b := getBinder()
+
+			if err := b.DoString(test.src); err != nil {
+				switch err.(type) {
+				case *Error:
+					e := err.(*Error)
+					if e.Error() != test.expected {
+						t.Errorf("Error message does not match, expected=\"%s\" got=\"%s\"", test.expected, e.Error())
+					}
+				default:
+					t.Error("Must return error", err)
+				}
+			}
+		})
+	}
+}
+
 func TestErrorSourceSmall_Func(t *testing.T) {
 	b := getBinder()