title: React setState does not set the state
body: <p>I am doing a simple react application and I have an App component which keeps track of the state and then renders it. At first the state it is an empty string. Afterwards when I access the /signin I click on a button that changes the state from "" to "Marc" and pass it via props to the Profile component who renders the name of the user on its page. The problem is that it does not change the state and it is always "". I tried to debug and the state is always "" but the method setState is actually called. So i do not know why. Can anyone help me? Thanks in advance and I enclose the code.</p>
  
  <p><strong>APP:</strong></p>
  
  <pre><code>export default class App extends React.Component {
  
      constructor(props) {
          super(props);
              this.state = {
              session: ""
          };
          this.updateUser = this.updateUser.bind(this);
      }
  
      updateUser() {
          this.setState({
              session: "Marc"
          });
      }
  
  render() {
      return(
          &lt;BrowserRouter&gt;
              &lt;Switch&gt;
                  &lt;Route path exact='/' component={Home}/&gt;
                  &lt;Route path='/profile' render={(props) =&gt; (
                      &lt;Profile session={this.state.session} /&gt; 
                  )}/&gt;                                            
                  &lt;Route path='/signin' render={(props) =&gt; (
                      &lt;SignIn onClick={this.updateUser} /&gt;
                  )}/&gt; 
              &lt;/Switch&gt;    
          &lt;/BrowserRouter&gt;
      );
  }
  
  }
  </code></pre>
  
  <p><strong>SIGNIN:</strong></p>
  
  <pre><code>export default class SignIn extends React.Component{
  
  constructor(props) {
      super(props);
      this.handleClick = this.handleClick.bind(this);
  }
  
  
  responseGoogle (googleUser) {
      const mail = googleUser.profileObj.email;
      const familyName = googleUser.profileObj.familyName;
      const name = googleUser.profileObj.name;
      //this.changeName(mail);
      alert("Mail: " + mail + "\n" + "Nom i Cognoms: " + name + "\nSuccessfully Logged In");
  }
  
  handleClick() {
      this.props.onClick();
  }
  
  render () {
      return (
      &lt;div&gt;
          &lt;GoogleLogin 
                      clientId="CLIENTID"
                      onSuccess={this.responseGoogle}
                      onFailure={this.responseGoogle}
                      buttonText="Google"/&gt;
          &lt;button onClick={this.handleClick}&gt;Instant User&lt;/button&gt;            
      &lt;/div&gt;
      );
  }
  
  }
  </code></pre>
  
  <p><strong>PROFILE:</strong></p>
  
  <pre><code>export default class Profile extends React.Component {
  
  constructor(props) {
      super(props)
  }
  
  
  render() {
      return(
          &lt;h1&gt;I am {this.props.session} User&lt;/h1&gt;
      );
  }
  }
  </code></pre>