Error on line 1, column 1 of pubspec.lock: Unexpected character

[MeshkaniMohammad]

I have a problem with upgrading packages. This problem occurred after cloning a repo and running flutter packages upgrade in the project.

[flutter_architecture_samples] flutter packages get
Building flutter tool...
Running pub upgrade...
Error on line 1, column 1 of pubspec.lock: Unexpected character.
  ╷
1 │ 
  │ ^
  ╵
Error (65): Unable to 'pub upgrade' flutter tool. Retrying in five seconds... (9 tries left)
Running pub upgrade...
Error on line 1, column 1 of pubspec.lock: Unexpected character.
  ╷
1 │ 
  │ ^
  ╵
Error (65): Unable to 'pub upgrade' flutter tool. Retrying in five seconds... (8 tries left)
Running pub upgrade...
Error on line 1, column 1 of pubspec.lock: Unexpected character.
  ╷
1 │ 
  │ ^
  ╵
Error (65): Unable to 'pub upgrade' flutter tool. Retrying in five seconds... (7 tries left)
Running pub upgrade...
Error on line 1, column 1 of pubspec.lock: Unexpected character.
  ╷
1 │ 
  │ ^
  ╵
Error (65): Unable to 'pub upgrade' flutter tool. Retrying in five seconds... (6 tries left)
Running pub upgrade...
Error on line 1, column 1 of pubspec.lock: Unexpected character.
  ╷
1 │ 
  │ ^
  ╵

here is all errors. and after this, I wasn't able to run flutter doctor or flutter upgrade
I'm in channel master and latest version of flutter.

[l-k22]

what happens if you delete the lock file?

[MeshkaniMohammad]

@l-k22 I didn't try it because I couldn't find that file. anyway, I solved the problem by reinstalling flutter.
for reinstalling flutter look at this link.

[l-k22]

Cool. You should close this since you've managed to solve it

[rohitsainik]

can you share your lock file with me

[MillerAdulu]

Delete the file at flutter/packages/flutter_tools/pubspec.lock then try flutter pub upgrade again.

You may have interrupted the upgrade process before it finished hence the file became invalid.

[mayoreee]

@MillerAdulu Thanks so much!
This worked for me.
The trick - I simply replaced the broken pubspec.lock file in my project directory with the newly generated pubspec.lock file.

[BalanaguYashwanth]

No need to replace with new file, Just delete it the PUBSPEC.LOCK file and then run the flutter run
it will automatically generate the new PUBSPEC.LOCK fie

It will solve your problem😊😊😊

[github-actions]

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.