[gentoo-catalyst] rfc: merging catalyst git branches

[gentoo-catalyst] rfc: merging catalyst git branches

[William Hubbs]

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All,

this has been mentioned in a couple of threads, so I want to bring it up
in a separate thread so that we can keep the discussions organized. :-)

As you know, catalyst has two branches in its git repository, master,
which was going to be catalyst 3.0, and a branch called catalyst_2 which
is the branch being used by releng for official releases.

We know from what Jorge said that the master branch is broken.

Right now, we are commiting changes to both branches, but that is not a
good idea over the long term. We need to figure out if we should keep
master and try to release 3.0 from there at some point.  If that is what
we want to do, we need to go through the catalyst_2 branch and port
relevant commits to master.

If we are not interested in the 3.0 code, we should probably find a way
to revert all of it from master with one commit then rebase the 2.0
branch on master and move it back there.

What are your thoughts, especially releng, because you did a lot of work
on the 3.0 code. If we port commits from catalyst_2 to the 3.0 branch,
can we get that code up and running? What commits on that branch should
be ported?

William


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Re: [gentoo-catalyst] rfc: merging catalyst git branches

[William Hubbs]

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On Sun, Jun 26, 2011 at 11:44:33PM -0500, William Hubbs wrote:
> All,
> 
> this has been mentioned in a couple of threads, so I want to bring it up
> in a separate thread so that we can keep the discussions organized. :-)
> 
> As you know, catalyst has two branches in its git repository, master,
> which was going to be catalyst 3.0, and a branch called catalyst_2 which
> is the branch being used by releng for official releases.
> 
> We know from what Jorge said that the master branch is broken.
> 
> Right now, we are commiting changes to both branches, but that is not a
> good idea over the long term. We need to figure out if we should keep
> master and try to release 3.0 from there at some point.  If that is what
> we want to do, we need to go through the catalyst_2 branch and port
> relevant commits to master.
> 
> If we are not interested in the 3.0 code, we should probably find a way
> to revert all of it from master with one commit then rebase the 2.0
> branch on master and move it back there.

If no one objects, I will look into doing this next week; the catalyst_2
code should move to master since there doesn't appear to be any work
going on for releasing catalyst 3.

Comments?

William


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Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Sebastian Pipping]

On 12/08/2011 08:46 PM, William Hubbs wrote:
>> [..]
>>
>> If we are not interested in the 3.0 code, we should probably find a way
>> to revert all of it from master with one commit then rebase the 2.0
>> branch on master and move it back there.
> 
> If no one objects, I will look into doing this next week; the catalyst_2
> code should move to master since there doesn't appear to be any work
> going on for releasing catalyst 3.
> 
> Comments?

Sounds like you are going for complete replacement.  Good move.


The cleanest way to do this this in Git may be:

  # git checkout master
  # git merge -s theirs catalyst_2

Haven't tested it though.

Best,



Sebastian

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[William Hubbs]

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On Thu, Dec 08, 2011 at 09:31:26PM +0100, Sebastian Pipping wrote:
> On 12/08/2011 08:46 PM, William Hubbs wrote:
> > If no one objects, I will look into doing this next week; the catalyst_2
> > code should move to master since there doesn't appear to be any work
> > going on for releasing catalyst 3.
> > 
> > Comments?
> 
> Sounds like you are going for complete replacement.  Good move.
> 
> 
> The cleanest way to do this this in Git may be:
> 
>   # git checkout master
>   # git merge -s theirs catalyst_2
> 
> Haven't tested it though.

I checked it out with the folks on #git, and they are recommending
that I rename catalyst_2 to master. I was given a series of commands to
do this.

The down side is that this will cause a forced update, so everyone will
have to re-clone the repository.

The target time I am considering for this is Monday, Dec 11, 0:00 utc.
What that means is, everyone needs to have their changes pushed by then,
then I'll make the change and send out an email here once I'm done.
Then, you will have to re-clone your repositories.

Any comments?

Thanks,

William


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Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Sebastian Pipping]

On 12/08/2011 10:42 PM, William Hubbs wrote:
>> The cleanest way to do this this in Git may be:
>>
>>   # git checkout master
>>   # git merge -s theirs catalyst_2
>>
>> Haven't tested it though.

Just noticed that I mis-read the git-merge man page: "theirs" is an
option of the recursive merge strategy.  Sorry.


> I checked it out with the folks on #git, and they are recommending
> that I rename catalyst_2 to master. I was given a series of commands to
> do this.
> 
> The down side is that this will cause a forced update, so everyone will
> have to re-clone the repository.

Actually there is a way to do this *without* the downside that you describe.

The trick is to create a fake merge commit using git commit-tree to sort
of emulate merge strategy "theirs".  The commit to make needs to:

 - point to catalyst_2^{tree} as its content.

 - have current catalyst_2 as its *first* parent in order to
   - indicate where the data actually came from
   - make commands like "git show HEAD^" descend into
     the old catalyst_2 branch later as that's the content
     that matters

 - have current master as the second parent
   (so people can keep working without trouble)


This time I tested it myself.  This is what to do:

  1)  Make sure your local master and catalyst are *both* up to date.

  2)  # git checkout master

  3)  Create and merge a fake merge commit as defined above:

        # git merge $(git commit-tree catalyst_2^{tree} \
          -p catalyst_2 -p master \
          <<<"Replace content on master with content from catalyst_2")

      Again, the *order* of parents matters.

  4)  Confirm it went fine, e.g. this diff should now be empty:

      # git diff master catalyst_2


> The target time I am considering for this is Monday, Dec 11, 0:00 utc.
> What that means is, everyone needs to have their changes pushed by then,
> then I'll make the change and send out an email here once I'm done.
> Then, you will have to re-clone your repositories.
> 
> Any comments?

Please consider the alternative explained above.

What do you think?


Best,



Sebastian

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Jorge Manuel B. S. Vicetto]

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Hash: SHA1

On 08-12-2011 18:46, William Hubbs wrote:
> On Sun, Jun 26, 2011 at 11:44:33PM -0500, William Hubbs wrote:
>> All,
>> 
>> this has been mentioned in a couple of threads, so I want to
>> bring it up in a separate thread so that we can keep the
>> discussions organized. :-)
>> 
>> As you know, catalyst has two branches in its git repository,
>> master, which was going to be catalyst 3.0, and a branch called
>> catalyst_2 which is the branch being used by releng for official
>> releases.
>> 
>> We know from what Jorge said that the master branch is broken.
>> 
>> Right now, we are commiting changes to both branches, but that is
>> not a good idea over the long term. We need to figure out if we
>> should keep master and try to release 3.0 from there at some
>> point.  If that is what we want to do, we need to go through the
>> catalyst_2 branch and port relevant commits to master.
>> 
>> If we are not interested in the 3.0 code, we should probably find
>> a way to revert all of it from master with one commit then rebase
>> the 2.0 branch on master and move it back there.
> 
> If no one objects, I will look into doing this next week; the
> catalyst_2 code should move to master since there doesn't appear to
> be any work going on for releasing catalyst 3.
> 
> Comments?

William,

I'd rather not lose the work for catalyst_3. I understand and agree we
use the catalyst_2 branch for our releases, so I'd rather move master
to a new branch, call it catalyst_3, experimental or something else,
and then make catalyst_2 as master.


> William
> 

- -- 
Regards,

Jorge Vicetto (jmbsvicetto) - jmbsvicetto at gentoo dot org
Gentoo- forums / Userrel / Devrel / KDE / Elections / RelEng
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Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Sebastian Pipping]

On 12/09/2011 02:55 AM, Jorge Manuel B. S. Vicetto wrote:
> I'd rather not lose the work for catalyst_3. I understand and agree we
> use the catalyst_2 branch for our releases, so I'd rather move master
> to a new branch, call it catalyst_3, experimental or something else,
> and then make catalyst_2 as master.

The code remains in Git, we don't really lose it.
To easy up accessing it in the future, all you need to do now is

 A) add a tag or

 B) start a branch

where the master branch is now, as you prefer.

Best,



Sebastian

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[William Hubbs]

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On Fri, Dec 09, 2011 at 12:55:38AM -0100, Jorge Manuel B. S. Vicetto wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> On 08-12-2011 18:46, William Hubbs wrote:
> > On Sun, Jun 26, 2011 at 11:44:33PM -0500, William Hubbs wrote:
> >> All,
> >> 
> >> this has been mentioned in a couple of threads, so I want to
> >> bring it up in a separate thread so that we can keep the
> >> discussions organized. :-)
> >> 
> >> As you know, catalyst has two branches in its git repository,
> >> master, which was going to be catalyst 3.0, and a branch called
> >> catalyst_2 which is the branch being used by releng for official
> >> releases.
> >> 
> >> We know from what Jorge said that the master branch is broken.
> >> 
> >> Right now, we are commiting changes to both branches, but that is
> >> not a good idea over the long term. We need to figure out if we
> >> should keep master and try to release 3.0 from there at some
> >> point.  If that is what we want to do, we need to go through the
> >> catalyst_2 branch and port relevant commits to master.
> >> 
> >> If we are not interested in the 3.0 code, we should probably find
> >> a way to revert all of it from master with one commit then rebase
> >> the 2.0 branch on master and move it back there.
> > 
> > If no one objects, I will look into doing this next week; the
> > catalyst_2 code should move to master since there doesn't appear to
> > be any work going on for releasing catalyst 3.
> > 
> > Comments?
> 
> William,
> 
> I'd rather not lose the work for catalyst_3. I understand and agree we
> use the catalyst_2 branch for our releases, so I'd rather move master
> to a new branch, call it catalyst_3, experimental or something else,
> and then make catalyst_2 as master.

Hi Jorge,

Ok, no problem, I'll go back to the #git channel tomorrow and
investigate how to do that.

I would prefer to do it without merge commits if possible, but that may
mean a forced update. Are you ok with that?

William


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Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Sebastian Pipping]

On 12/09/2011 04:19 AM, William Hubbs wrote:
> Hi Jorge,
> 
> Ok, no problem, I'll go back to the #git channel tomorrow and
> investigate how to do that.

Have you received my other mail with notes on git commit-tree and how it
can help here?  It was sent "Fri, 09 Dec 2011 00:43:45 +0100".


> I would prefer to do it without merge commits if possible

What would be the gain here?


>, but that may
> mean a forced update. Are you ok with that?

I would rather not see that.  Is there is a problem with the git
commit-tree approach that you see but I don't?  Please let me hear about it.

Best,




Sebastian

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[William Hubbs]

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On Fri, Dec 09, 2011 at 05:42:03AM +0100, Sebastian Pipping wrote:
> On 12/09/2011 04:19 AM, William Hubbs wrote:
> > Hi Jorge,
> > 
> > Ok, no problem, I'll go back to the #git channel tomorrow and
> > investigate how to do that.
> 
> Have you received my other mail with notes on git commit-tree and how it
> can help here?  It was sent "Fri, 09 Dec 2011 00:43:45 +0100".
 
 Yes, I saw it, but it doesn't seem to do what we want. It merges the
 branches together instead of swapping them.

> > I would prefer to do it without merge commits if possible

What I want is something like:

git branch -m master catalyst_3
git branch -m catalyst_2 master
# now update the upstream repo to match this.
# I'm not sure if this will cause a forced update or not though.

> 
> What would be the gain here?
 
 The gain is that git log doesn't show a merge commit, and you aren't
 pushing another 70 plus commits to the master branch, so you keep the
 history clean.

Best,

William


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Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Matt Turner]

On Fri, Dec 9, 2011 at 11:16 AM, William Hubbs <williamh@gentoo.org> wrote:
> On Fri, Dec 09, 2011 at 05:42:03AM +0100, Sebastian Pipping wrote:
>> On 12/09/2011 04:19 AM, William Hubbs wrote:
>> > Hi Jorge,
>> >
>> > Ok, no problem, I'll go back to the #git channel tomorrow and
>> > investigate how to do that.
>>
>> Have you received my other mail with notes on git commit-tree and how it
>> can help here?  It was sent "Fri, 09 Dec 2011 00:43:45 +0100".
>
>  Yes, I saw it, but it doesn't seem to do what we want. It merges the
>  branches together instead of swapping them.
>
>> > I would prefer to do it without merge commits if possible
>
> What I want is something like:
>
> git branch -m master catalyst_3
> git branch -m catalyst_2 master
> # now update the upstream repo to match this.
> # I'm not sure if this will cause a forced update or not though.
>
>>
>> What would be the gain here?
>
>  The gain is that git log doesn't show a merge commit, and you aren't
>  pushing another 70 plus commits to the master branch, so you keep the
>  history clean.

What Sebastian was suggesting was this, which works (I just verified locally)

git checkout master
git branch catalyst_3 # creates a branch identical to master called catalyst_3
git branch -M catalyst_2 master # renames the catalyst_2 branch to master

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Sebastian Pipping]

On 12/09/2011 06:37 PM, Matt Turner wrote:
> What Sebastian was suggesting was this, which works (I just verified locally)
> 
> git checkout master
> git branch catalyst_3 # creates a branch identical to master called catalyst_3
> git branch -M catalyst_2 master # renames the catalyst_2 branch to master

No, step three uses git commit-tree and git merge in my approach -- it's
not a rename.




Sebastian

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Sebastian Pipping]

On 12/09/2011 05:16 PM, William Hubbs wrote:
>  Yes, I saw it, but it doesn't seem to do what we want. It merges the
>  branches together instead of swapping them.

Maybe it's not what _you_ want, but it does

 - make catalyst_2 content appear on master

 - doesn't break fast forward "git pull" for anyone

 - supports branching catalyst_2 off master, too

So besides the merge commit, this can look like rename from the outside.


>>> I would prefer to do it without merge commits if possible
> 
> What I want is something like:
> 
> git branch -m master catalyst_3
> git branch -m catalyst_2 master
> # now update the upstream repo to match this.
> # I'm not sure if this will cause a forced update or not though.

It does, a forced push would be necessary:
you are pushing commits to master that are not successors of the remote
master's HEAD.


>> What would be the gain here?
>  
>  The gain is that git log doesn't show a merge commit, and you aren't
>  pushing another 70 plus commits to the master branch, so you keep the
>  history clean.

A clean history is *not* a history without merge commits but a history
reflecting what happened in reality.  There are cases where it makes
sens to even force a merge commit using git merge --no-ff to clearly
indicate that a dedicated branch was merged back.

Best,



Sebastian

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[William Hubbs]

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On Fri, Dec 09, 2011 at 07:48:52PM +0100, Sebastian Pipping wrote:
> On 12/09/2011 05:16 PM, William Hubbs wrote:
> >  Yes, I saw it, but it doesn't seem to do what we want. It merges the
> >  branches together instead of swapping them.
> 
> Maybe it's not what _you_ want, but it does
> 
>  - make catalyst_2 content appear on master
> 
>  - doesn't break fast forward "git pull" for anyone
> 
>  - supports branching catalyst_2 off master, too

The method you are suggesting does _NOT_ make the current content of
master appear on catalyst_3, which is the other part of what releng is
requesting.

What I think I can do, but I'm not quite sure how to do it, is:

1) create a catalyst_3 branch at the same point in history where
catalyst_2 was created. I believe I can accomplish this with

git branch catalyst_3 $(git merge-base master catalyst_2)

2) put the code on master that is _NOT_ on catalyst_2 on catalyst_3.

Any suggestions for how to do this?

3) put the code on catalyst_2 on master.

What about this?

William


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Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Sebastian Pipping]

On 12/10/2011 03:45 PM, William Hubbs wrote:
>>  - supports branching catalyst_2 off master, too

s/catalyst_2/catalyst_3/


> The method you are suggesting does _NOT_ make the current content of
> master appear on catalyst_3, which is the other part of what releng is
> requesting.

That's a trivial addition.  With it, the full run on my shell:

 # git branch catalyst_3 master

 # git checkout master

 # git merge $(git commit-tree catalyst_2^{tree} \
     -p catalyst_2 -p master \
     <<<"Replace content on master with content from catalyst_2")

 # git push origin master

 # git push origin catalyst_3


Results is:

 - 2.x content on branch master (and catalyest_2)

 - 3.x content on branch catalyest_3


> What I think I can do, but I'm not quite sure how to do it, is:
> 
> 1) create a catalyst_3 branch at the same point in history where
> catalyst_2 was created. I believe I can accomplish this with
> 
> git branch catalyst_3 $(git merge-base master catalyst_2)

The branch head is moving along with each commit so it would end up at
the current master in the end, anyway.

If you like to mark the point where catalyst 3.x was started, a tag
would be the right tool, not a branch.


> 2) put the code on master that is _NOT_ on catalyst_2 on catalyst_3.
> 
> Any suggestions for how to do this?

I'm not sure what you mean by that.


> 3) put the code on catalyst_2 on master.
> 
> What about this?

Either git commit-tree or forced push.

Best,



Sebastian

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Peter Stuge]

Sebastian Pipping wrote:
> > 3) put the code on catalyst_2 on master.
> > 
> > What about this?
> 
> Either git commit-tree or forced push.

git commit-tree is the better way. Sometimes it is neccessary to
rewrite public history, but this is not one of those times.

Whenever it is not absolutely neccessary, it's better to do something
else on the branch than rewrite it - unless the branch is well known
to be rewritten (like a testing branch might be).

catalyst master is not a testing branch and shouldn't be rewritten.

William, please go with Sebastian's suggestion.


//Peter

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Sebastian Pipping]

On 12/10/2011 11:15 PM, Sebastian Pipping wrote:
> [T]he full run on my shell:
> 
>  # git branch catalyst_3 master
> 
>  # git checkout master
> 
>  # git merge $(git commit-tree catalyst_2^{tree} \
>      -p catalyst_2 -p master \
>      <<<"Replace content on master with content from catalyst_2")
> 
>  # git push origin master
> 
>  # git push origin catalyst_3
> 
> 
> Results is:
> 
>  - 2.x content on branch master (and catalyst_2)
> 
>  - 3.x content on branch catalyst_3

This procedure above is still left to do.  Any objections?
With no objections, I will go forward on next monday (2012-07-02).

Best,



Sebastian

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Matt Turner]

On Sun, Jun 24, 2012 at 7:33 PM, Sebastian Pipping <sping@gentoo.org> wrote:
> On 12/10/2011 11:15 PM, Sebastian Pipping wrote:
>> [T]he full run on my shell:
>>
>>  # git branch catalyst_3 master
>>
>>  # git checkout master
>>
>>  # git merge $(git commit-tree catalyst_2^{tree} \
>>      -p catalyst_2 -p master \
>>      <<<"Replace content on master with content from catalyst_2")
>>
>>  # git push origin master
>>
>>  # git push origin catalyst_3
>>
>>
>> Results is:
>>
>>  - 2.x content on branch master (and catalyst_2)
>>
>>  - 3.x content on branch catalyst_3
>
> This procedure above is still left to do.  Any objections?
> With no objections, I will go forward on next monday (2012-07-02).

If you're confident it'll work -- please proceed. No use in waiting.

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Sebastian Pipping]

On 06/25/2012 06:04 AM, Matt Turner wrote:
> On Sun, Jun 24, 2012 at 7:33 PM, Sebastian Pipping <sping@gentoo.org> wrote:
>> On 12/10/2011 11:15 PM, Sebastian Pipping wrote:
>>> [T]he full run on my shell:
>>>
>>>  # git branch catalyst_3 master
>>>
>>>  # git checkout master
>>>
>>>  # git merge $(git commit-tree catalyst_2^{tree} \
>>>      -p catalyst_2 -p master \
>>>      <<<"Replace content on master with content from catalyst_2")
>>>
>>>  # git push origin master
>>>
>>>  # git push origin catalyst_3
>>>
>>>
>>> Results is:
>>>
>>>  - 2.x content on branch master (and catalyst_2)
>>>
>>>  - 3.x content on branch catalyst_3
>>
>> This procedure above is still left to do.  Any objections?
>> With no objections, I will go forward on next monday (2012-07-02).
> 
> If you're confident it'll work -- please proceed. No use in waiting.

Done.

Best,



Sebastian

Re: [gentoo-catalyst] rfc: merging catalyst git branches

[Matt Turner]

On Mon, Jul 2, 2012 at 10:55 AM, Sebastian Pipping <sping@gentoo.org> wrote:
> Done.

Great. Thank you, Sebastian. I was able to git pull my branches and
didn't have any trouble.

Matt