Not able to solve Unhandled Exception: Stack Overflow

Question

I am trying to create a signUp page in flutter using Firebase Authentication. I ran into this error and I am not able to solve this please help me.

This is the SignUp page code

import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';

class SignUp extends StatefulWidget {
  @override
  _SignUpState createState() => _SignUpState();
}

class _SignUpState extends State<SignUp> {
  FirebaseAuth _auth = FirebaseAuth.instance;
  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();

  late String _name, _email, _password;

  checkAuthentication() async {
    _auth.authStateChanges().listen((user) async {
      if (user != null) {
        Navigator.pushReplacementNamed(context, "/");
      }
    });
  }

  @override
  void initState() {
    super.initState();
    this.checkAuthentication();
  }

  signUp() async {
    if (_formKey.currentState!.validate()) {
      _formKey.currentState!.save();

      try {
        UserCredential user = await _auth.createUserWithEmailAndPassword(
            email: _email, password: _password);
        await _auth.currentUser!.updateProfile(displayName: _name);
      } catch (e) {
        showError(e.toString());
        print(e);
      }
    }
  }

  showError(String errormessage) {
    showDialog(
        context: context,
        builder: (BuildContext context) {
          return AlertDialog(
            title: Text('ERROR'),
            content: Text(errormessage),
            actions: <Widget>[
              FlatButton(
                  onPressed: () {
                    Navigator.of(context).pop();
                  },
                  child: Text('OK'))
            ],
          );
        });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
        body: SingleChildScrollView(
      child: Container(
        child: Column(
          children: <Widget>[
            SizedBox(height: 50),
            Container(
              child: Image(
                height: 200,
                width: 200,
                image: AssetImage("images/signuppic.png"),
                fit: BoxFit.contain,
              ),
            ),
            Container(
              child: Form(
                key: _formKey,
                child: Column(
                  children: <Widget>[
                    Container(
                      child: TextFormField(
                          validator: (input) {
                            if (input!.isEmpty) return 'Enter Name';
                          },
                          decoration: InputDecoration(
                            labelText: 'Name',
                            prefixIcon: Icon(Icons.person),
                          ),
                          onSaved: (input) => _name = input!),
                    ),
                    SizedBox(height: 20),
                    Container(
                      child: TextFormField(
                          validator: (input) {
                            if (input!.isEmpty) return 'Enter Email';
                          },
                          decoration: InputDecoration(
                              labelText: 'Email',
                              prefixIcon: Icon(Icons.email)),
                          onSaved: (input) => _email = input!),
                    ),
                    SizedBox(height: 20),
                    Container(
                      child: TextFormField(
                          validator: (input) {
                            if (input!.length < 6)
                              return 'Provide Minimum 6 Character';
                          },
                          decoration: InputDecoration(
                            labelText: 'Password',
                            prefixIcon: Icon(Icons.lock),
                          ),
                          obscureText: true,
                          onSaved: (input) => _password = input!),
                    ),
                    SizedBox(height: 40),
                    RaisedButton(
                      padding: EdgeInsets.fromLTRB(70, 10, 70, 10),
                      onPressed: signUp,
                      child: Text('SignUp',
                          style: TextStyle(
                              color: Colors.white,
                              fontSize: 20.0,
                              fontWeight: FontWeight.bold)),
                      color: Colors.orange,
                      shape: RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(20.0),
                      ),
                    )
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    ));
  }
}

This is the error I am getting

Restarted application in 2,098ms.
2
D/InputConnectionAdaptor( 9914): The input method toggled cursor monitoring on
I/TextInputPlugin( 9914): Composing region changed by the framework. Restarting the input method.
2
D/InputConnectionAdaptor( 9914): The input method toggled cursor monitoring on
E/flutter ( 9914): [ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: Stack Overflow
E/flutter ( 9914): #0      Element.markNeedsBuild.<anonymous closure>
package:flutter/…/widgets/framework.dart:4402
E/flutter ( 9914): #1      Element.markNeedsBuild
package:flutter/…/widgets/framework.dart:4439
E/flutter ( 9914): #2      State.setState
package:flutter/…/widgets/framework.dart:1141
E/flutter ( 9914): #3      FormState._forceRebuild
package:flutter/…/widgets/form.dart:121
E/flutter ( 9914): #4      FormState.validate
package:flutter/…/widgets/form.dart:183
E/flutter ( 9914): #5      FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #6      FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #7      FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #8      FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #9      FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #10     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #11     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #12     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #13     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #14     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #15     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #16     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #17     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #18     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #19     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #20     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #21     FormState.validate
package:flutter/…/widgets/form.dart:184
E/flutter ( 9914): #22     FormState.validate
package:flutter/…/widgets/form.dart:184

I didn't come across anyone who got this error. Is it a bug in Firebase Authentication error or Flutter Widget error?