startConditions error

[ichiriac]

I'm using latest jison version for generating a parser and i've got this error :

...\node_modules\jison\node_modules\jison-lex\regexp-lexer.js:44
                  startConditions[conditions[k]].rules.push(i);
                                                ^
TypeError: Cannot read property 'rules' of undefined
    at prepareRules (...\node_modules\jison\node_modules\jison-lex\regexp-lexer.js:44:49)
    at Object.buildActions (...\node_modules\jison\node_modules\jison-lex\regexp-lexer.js:115:18)
    at Object.RegExpLexer (...\node_modules\jison\node_modules\jison-lex\regexp-lexer.js:141:39)
    at Jison_Generator (...\node_modules\jison\lib\jison.js:111:22)
    at (anonymous function) (...\node_modules\jison\lib\util\typal.js:23:28)
    at new o.constructor (...\node_modules\jison\lib\util\typal.js:77:70)
    at Object.Jison_Generator [as Generator] (...\node_modules\jison\lib\jison.js:1740:20)
    at new Parser (...\node_modules\jison\lib\jison.js:1745:25)

To reproduce this issue you can use this syntax file :

/* BUG : TypeError: Cannot read property 'rules' of undefined */

%lex

%x INITIAL

%%

<INITIAL>"{" %{
  this.begin('BRACKET');
  console.log('{');
%}
<BRACKET>"}" %{
  this.popState();
  console.log('}');
%}

/lex

%start start

%%

start: [^];

I've tried to change regexp-lexer.js line 43 with the following, but I'm not sure :

  if (startConditions.hasOwnProperty(conditions[k])) {
    startConditions[conditions[k]].rules.push(i);
  }