More Git Fu (RE: [csmith-project/csmith] 4ba524: fix a bug...)

[Eric Eide <eeide@cs.utah.edu>]

[CC'ed Ryan Jackson, the flux-local Git expert, to review my answer.]

	Xuejun> I run into this situation a couple of times: I forget, or
	Xuejun> didn't realize I need, to pull on master branch before
	Xuejun> rebasing+merging the topic branch. Once the merge is done, the
	Xuejun> damage is done. Even if I pull on the master again, and redo
	Xuejun> rebasing + merging with the topic branch, I lost the capability
	Xuejun> of fast forwarding.  My questions are:

Easy question first:

	Xuejun> 2) even better, is there a way automatically pull on the master
	Xuejun>    branch whenever somebody else commits while I am working on
	Xuejun>    a topic branch?

No, not automatically.

	Xuejun> 1) if there a way to back out from the 1st rebasing+merging. I
	Xuejun>    remember I tried stash, but it didn't work.

Let me see if I have this right.  You merge a topic branch into your master;
let's assume this is a fast-forward merge.  So you get something like this:

		origin/master			master
		|				topic
	o ----> o ----> o ----> o ----> o ----> o

Then you pull, and git does something like this:

							origin/master
			(stuff pulled from origin)	master
	o ----> o ----> O ----> O --------------------> o
		|					^
		\-----> o ----> o ----> o ----> o ------/
						topic

where that last commit is the merge created for you by git.

The way to get out of this, I believe, is: git reset --merge ORIG_HEAD
That should give you this:

				origin/master
	o ----> o ----> O ----> O
		|
		\-----> o ----> o ----> o ----> o 
						topic
						master

There's no need to move origin/master back, and you don't really want to
anyway.

At this point you can: git rebase origin/master
yielding:

				origin/master
	o ----> o ----> O ----> O
				|
				\-----> o ----> o ----> o ----> o 
								topic
								master

And then: git push

Eric.

-- 
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Eric Eide <eeide@cs.utah.edu>  .         University of Utah School of Computing
http://www.cs.utah.edu/~eeide/ . +1 (801) 585-5512 voice, +1 (801) 581-5843 FAX