0.0"
    echo "No previous version found. Starting with version 1.0.0"
fi

docker tag auth-proxy "946207870883.dkr.ecr.us-east-1.amazonaws.com/$REPOSITORY_NAME:$TAG"
docker push "946207870883.dkr.ecr.us-east-1.amazonaws.com/$REPOSITORY_NAME:$TAG"

# ... rest of the existing code ...
```

This modification adds a check after determining the TAG. If the TAG is empty (which could happen if there are no previous versions in the repository), it sets the TAG to "1.0.0" and prints a message to inform the user.

This change ensures that even if there are no previous versions or if the version determination fails for some reason, the script will still proceed with a valid initial version number.