Fix infinite loop bug in lexer

qcode/lex.go

@@ -398,7 +398,7 @@ func isSpace(r rune) bool {
 
 // isEndOfLine reports whether r is an end-of-line character.
 func isEndOfLine(r rune) bool {
-	return r == '\r' || r == '\n'
+	return r == '\r' || r == '\n' || r == eof
 }
 
 // isAlphaNumeric reports whether r is an alphabetic, digit, or underscore.

qcode/parse_test.go

@@ -58,6 +58,14 @@ func TestCompile(t *testing.T) {
 	}
 }
 
+func TestInvalidCompile(t *testing.T) {
+	qcompile, _ := NewCompiler(Config{})
+	_, err := qcompile.CompileQuery(`#`)
+	if err == nil {
+		t.Fatal(errors.New("expecting an error"))
+	}
+}
+
 func TestEmptyCompile(t *testing.T) {
 	qcompile, _ := NewCompiler(Config{})
 	_, err := qcompile.CompileQuery(``)

qcode/qcode.go

@@ -1,6 +1,7 @@
 package qcode
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 
@@ -355,6 +356,10 @@ func (com *Compiler) compileQuery(op *Operation) (*Query, error) {
 		}
 	}
 
+	if selRoot == nil {
+		return nil, errors.New("invalid query")
+	}
+
 	return &Query{selRoot}, nil
 }