Re: Switching branches without committing changes

> Jeff King <peff@peff.net> writes:
>
>> On Fri, Mar 21, 2008 at 12:06:47AM -0400, Shawn O. Pearce wrote:
>>
>>> Use `git checkout -m` to switch the branch anyway.  However, if
>>> there is a merge conflict while you are trying to carry the changes
>>> to the other branch you may be faced with a merge conflict you are
>>> not prepared to resolve, or simply cannot resolve in a reasonable
>>> period of time.
>>
>> Ah, for some reason I didn't think of '-m' in the advice I gave (I  
>> guess
>> I have just never used it). It is almost certainly simpler than  
>> using a
>> 'stash' at this point (but I do think stashing _beforehand_ still has
>> advantages).
>
> The thing is, that -m is really to mollify people who are _too_  
> accustomed
> to CVS/SVN update behaviour.  Over there, "scm update" does not give  
> you
> any choice other than having to merge.
>
> With git, stashing or creating Park commits are very cheap operation  
> and
> unless you are reasonably sure that your local changes do not conflict
> with the branch you are switching to, there is no strong reason to  
> prefer
> "checkout -m".
>
> Switching branches with dirty state can have three scenarios:
>
> (1) you are getting interrupted and your current local changes do not
>     belong to what you are going to commit after switching (e.g. "the
>     boss says fix that right away").
>
>     recommendation: stash, or Park commit
>
> (2) you have started working but realized what you are working on  
> belongs
>     to a new topic.
>
>     recommendation: checkout -b
>
> (3) you have started working but realized what you are working on  
> belongs
>     to an existing topic.
>
>     recommendation: checkout -m
>
> In case (1), if the change is small, trivial or independent from  
> what you
> are switching branches to work on, you can "git checkout" (if the  
> change
> is about an unrelated thing, hopefully there won't be any overlap at  
> the
> file level) or "git checkout -m" (again, if the change is about an
> unrelated thing, the merge hopefully would be trivial) to switch  
> branches,
> perform the unrelated change and commit only that unrelated change,  
> and
> "git checkout" (or "git checkout -m") to come back to where you  
> started.
> But if you had to use "-m" when switching branches, that means the  
> change
> you need to commit in the switched branch may have to include some  
> changes
> you will do to that modified file, and you would need per-hunk  
> commit with
> "git add -i" to exclude existing changes.  In such a case, stashing  
> the
> local changes away before branch switching would be much easier  
> workflow.
>
> In case (2), the solution is always "checkout -b".  There is no other
> choice.
>
> In case (3), the solution is always "checkout -m".  Stashing,  
> switching
> and then unstashing will give the same conflicts as "checkout -m"  
> would
> give you, and the change you were working on has to be done on that
> switched to branch, so there is no escaping from conflict resolution,
> unless you are willing to redo your change on the breanch you  
> switched to
> again.
>
>
>
>