當要push代碼到git時，出現提示：
error:failed to push some refs to ...
Dealing with “non-fast-forward” errors
From time to time you may encounter this error while pushing:
- $ git push origin master
- To ../remote/
- ! [rejected] master -> master (non-fast forward)
- error: failed to push some refs to '../remote/'
To prevent you from losing history, non-fast-forward updates were rejected
Merge the remote changes before pushing again. See the 'non-fast forward'
section of 'git push --help' for details.
This error can be a bit overwhelming at first, do not fear. Simply put, git cannot make the change on the remote without losing commits, so it refuses the push. Usually this is caused by another user pushing to the same branch. You can remedy this by fetching and merging the remote branch, or using pull to perform both at once.
In other cases this error is a result of destructive changes made locally by using commands like git commit --amend or git rebase. While you can override the remote by adding --force to the push command, you should only do so if you are absolutely certain this is what you want to do. Force-pushes can cause issues for other users that have fetched the remote branch, and is considered bad practice. When in doubt, don’t force-push.
問題（Non-fast-forward）的出現原因在於：git倉庫中已經有一部分代碼，所以它不允許你直接把你的代碼覆蓋上去。於是你有2個選擇方式：
1，強推，即利用強覆蓋方式用你本地的代碼替代git倉庫內的內容
git push -f
2，先把git的東西fetch到你本地然後merge後再push
$ git fetch
$ git merge
這2句命令等價於
- $ git pull
可是，這時候又出現了如下的問題：
上面出現的 [branch "master"]是需要明確(.git/config)如下的內容
[branch "master"]
remote = origin
merge = refs/heads/master
這等於告訴git2件事:
1，當你處於master branch, 默認的remote就是origin。
2，當你在master branch上使用git pull時，沒有指定remote和branch，那麼git就會采用默認的remote（也就是origin）來merge在master branch上所有的改變
如果不想或者不會編輯config文件的話，可以在bush上輸入如下命令行：
- $ git config branch.master.remote origin
- $ git config branch.master.merge refs/heads/master
之後再重新git pull下。最後git push你的代碼吧。it works now~
