On Mon, May 08, 2017 at 12:05:31PM +0900, Junio C Hamano wrote: > Yubin Ruan <ablacktshirt@xxxxxxxxx> writes: > > > I think it would be better if git can warn use if we switch to another branch > > without committing the modification. Git will warn if the modification is based > > on a commit different from where the checkout happened. > > > > For example, say I am now on branch 'master' and all files *clean*. Now if I do: > > $ git checkout -b issue > > and make some changes to a file: > > $ echo "modification on branch issue" >> lala.txt > > and then switch back to branch 'master': > > $ git checkout master > > and git can see the changes: > > $ git status > > On branch master > > Changes not staged for commit: > > (use "git add <file>..." to update what will be committed) > > (use "git checkout -- <file>..." to discard changes in working directory) > > > > modified: lala.txt > > > > no changes added to commit (use "git add" and/or "git commit -a") > > > > Now, if I do "git checkout -- lala.txt", then I will lose that change on branch > > 'issue' too!!! > > There may be a fundamental misunderstanding here. In Git, changes > you make in the working tree do *not* belong to any branch. The > request "git checkout -- lala.txt" you made in this step does *not* > say "Hey, Git, these changes to lala.txt are not necessary in the > 'master' branch". It says "I started editing lala.txt, but it turns > out that I do not need that change at all, anywhere, please remove > it." I understand this. I just suggest that git add some warning in case some users are not aware of this, as it does when , on branch 'issue', changes to 'lala.txt' are based on a commit different from where the checkout happened, i.e. on branch 'master' | | <-- git checkout -b issue \ \ <-- modification to git happened on a commit different from where the checkout happened in this situation, git would warn us something like this: error: Your local changes to the following files would be overwritten by checkout: lala.txt Please, commit your changes or stash them before you can switch branches. Aborting > If you meant the changes while you were on "issues" branch were not > yet ready to be committed, but now you want to work on "master" > branch without having to worry about these changes, "git stash" may > be a useful tool. Alternatively, you can just create a temporary > commit while on "issues" branch before checking out "master" branch > to work on something else, and when you are ready to continue > working on the "issues" branch, check out "issues" branch and either > (1) start with "reset HEAD^" or (2) just continue working on it and > conclude with "commit --amend". Nice suggestion though. --- Yubin