MB-33028 - do not run match on empty data slice

fastMatcher.go

@@ -580,7 +580,7 @@ func (m *FastMatcher) matchExec(token tokenType, tokenData []byte, node *ExecNod
 			}
 		}
 	} else {
-		panic("invalid token read")
+		panic(fmt.Sprintf("invalid token read - tokenType: %v data: %v", token, string(tokenData)))
 	}
 
 	if node.After != nil {
@@ -713,6 +713,10 @@ func (m *FastMatcher) matchObjectOrArray(token tokenType, tokenData []byte, node
 func (m *FastMatcher) Match(data []byte) (bool, error) {
 	m.tokens.Reset(data)
 
+	if len(data) == 0 {
+		return false, nil
+	}
+
 	token, tokenData, err := m.tokens.Step()
 	if err != nil {
 		return false, err

filterExprParser_test.go

@@ -509,6 +509,7 @@ func TestFilterExpressionParser(t *testing.T) {
 	udMarsh, _ = json.Marshal(userData)
 	match, err = m.Match(udMarsh)
 	assert.True(match)
+	assert.Nil(err)
 
 	// Negative
 	_, _, err = NewFilterExpressionParser("fieldpath.`path = fieldPath2")
@@ -526,4 +527,16 @@ func TestFilterExpressionParser(t *testing.T) {
 	expr, err = fe.OutputExpression()
 	assert.Equal(ErrorMalformedParenthesis, err)
 
+	fe = &FilterExpression{}
+	err = parser.ParseString("TRUE", fe)
+	assert.Nil(err)
+	expr, err = fe.OutputExpression()
+	assert.Nil(err)
+	matchDef = trans.Transform([]Expression{expr})
+	assert.NotNil(matchDef)
+	m = NewFastMatcher(matchDef)
+	emptySlice := make([]byte, 0)
+	match, err = m.Match(emptySlice)
+	assert.False(match)
+	assert.Nil(err)
 }