linux-next: unnecessary merges in the v4l-dvb tree

linux-next: unnecessary merges in the v4l-dvb tree

[Stephen Rothwell]

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Hi Mauro,

I noticed that you have two unnecessary merges in the v4l-dvb tree
(git://linuxtv.org/mchehab/media-next.git#master).  This is not
entirely your fault.  Unfortunately, when you do

git merge <signed tag>

git will produce a merge commit even if it could have fast
forwarded :-(.  Consequently, you have commits 1ef24960ab78 ("Merge tag
'v3.18-rc1' into patchwork") and d6d41ba1cb38 ("Merge remote-tracking
branch 'linus/master' into patchwork") even though the patchwork branch
in each case is included in the tag being merged.

The only ways I know around this is to either merge the commit
associated with the tag or do a (hard) reset to the tag.

Linus, any thoughts?
-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au

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Re: linux-next: unnecessary merges in the v4l-dvb tree

[Mauro Carvalho Chehab]

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Hi Stephen,

Em Thu, 30 Oct 2014 09:24:45 +1100
Stephen Rothwell <sfr@canb.auug.org.au> escreveu:

> Hi Mauro,
> 
> I noticed that you have two unnecessary merges in the v4l-dvb tree
> (git://linuxtv.org/mchehab/media-next.git#master).  This is not
> entirely your fault.  Unfortunately, when you do
> 
> git merge <signed tag>
> 
> git will produce a merge commit even if it could have fast
> forwarded :-(.  Consequently, you have commits 1ef24960ab78 ("Merge tag
> 'v3.18-rc1' into patchwork") and d6d41ba1cb38 ("Merge remote-tracking
> branch 'linus/master' into patchwork") even though the patchwork branch
> in each case is included in the tag being merged.
> 
> The only ways I know around this is to either merge the commit
> associated with the tag or do a (hard) reset to the tag.

A hard reset to the tag would likely be a bad idea, as it would break
the sub-maintainers trees that are based on my tree.

I generally use "git pull" for that, as the man page says that the
default behavior is to do fast forward:
       "--ff
           When the merge resolves as a fast-forward, only update
	   the branch pointer, without creating a merge commit. 
	   This is the default behavior."

It seems that the man page is then outdated for signed tags, or,
eventually, we need to make --ff explicit on this case.

I'll try the approach of merging the associated commit next time,
but this is something that it is easy to forget.

> 
> Linus, any thoughts?

Regards,
Mauro

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Re: linux-next: unnecessary merges in the v4l-dvb tree

[Stephen Rothwell]

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Hi Mauro,

On Thu, 30 Oct 2014 08:09:34 -0200 Mauro Carvalho Chehab <mchehab@infradead.org> wrote:
>
> Em Thu, 30 Oct 2014 09:24:45 +1100
> Stephen Rothwell <sfr@canb.auug.org.au> escreveu:
> 
> > The only ways I know around this is to either merge the commit
> > associated with the tag or do a (hard) reset to the tag.
> 
> A hard reset to the tag would likely be a bad idea, as it would break
> the sub-maintainers trees that are based on my tree.

I should have said that I don't expect you to change your tree at the
moment, just for that reason.  But maybe next time.

> I generally use "git pull" for that, as the man page says that the
> default behavior is to do fast forward:
>        "--ff
>            When the merge resolves as a fast-forward, only update
> 	   the branch pointer, without creating a merge commit. 
> 	   This is the default behavior."
> 
> It seems that the man page is then outdated for signed tags, or,
> eventually, we need to make --ff explicit on this case.

I think that --ff overrides this behaviour.  Doing "git merge
'<tag>^{}'" works, but you can't use that with "git pull".

> I'll try the approach of merging the associated commit next time,
> but this is something that it is easy to forget.

I don't think it is a really big problem but it would be nicer for
everyone.

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au

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