git: No refs in common and none specified; doing no

创建新项目，clone后首次push,出现

$ git push  
No refs in common and none specified; doing nothing.  
Perhaps you should specify a branch such as 'master'.  
fatal: The remote end hung up unexpectedly  
error: failed to push some refs to 'file:///xxxxxxx.git'  

原因

Git找不到要提交的版本

解决

git push origin master