I get this error when deploying through Forge, but the strange thing is that some changes show up on my digitalocean server. But my new classe are not working as I expected.
The deployment error is like this :
2 files changed, 7 insertions(+), 7 deletions(-)
Loading composer repositories with package information
Installing dependencies from lock file
ssh into your server, and manually run composer install.
it will alert you to the same error, but a prompt will appear asking what you'd like to do with your changes. for me, i selected y (yes) to discard the changes.
then just click 'Deploy' within Forge again to make sure all of your normal scripts run.
I'm not exactly sure what the error is, because as I'm guessing it's the same for you, I never modified any vendor files.
The problem within the Forge deployment is most likely you're using composer install --no-interaction so composer doesn't know what you want to do.