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Re: [BUG] [git 2.16.1] yeeek ... my files are gone .. by git pull <otherRepositoryUrl>

From
Johannes Schindelin <johannes.schindelin@gmx.de>
Date
Feb 26, 2018, 23:33 UTC
Message-ID
<nycvar.QRO.7.76.6.1802270032520.56@ZVAVAG-6OXH6DA.rhebcr.pbec.zvpebfbsg.pbz>
In-Reply-To
<20180223064549.GA19791@sigill.intra.peff.net>
Hi Peff,
On Fri, 23 Feb 2018, Jeff King wrote:
Show 60 quoted lines
> On Fri, Feb 23, 2018 at 06:29:55AM +0100, "Marcel 'childNo͡.de' Trautwein" wrote:
> 
> > shows me a quite different behavior, so solely rebase not seems the
> > full problem BUT `--rebase=preserve` will .. o’man , really, is this
> > intended?
> 
> Yeah, the bug seems to be in --preserve-merges. Here's an easier
> reproduction:
> 
>   git init
>   >one && git add one && git commit -m one
>   git checkout --orphan other
>   git mv one two && git commit -m two
> 
>   git rebase --preserve-merges master
> 
> at which point we've dropped commit "two" and its files entirely.
> 
> I don't know much about how preserve-merges works. It looks like in the
> loop around git-rebase--interactive.sh:931 that we mark commit "two"
> with preserve=t, and so we _don't_ add it to the list of commits to
> pick.
> 
> I think that stems from the fact that it has no parent marked to be
> rewritten.
> 
> So something like this helps:
> 
> diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
> index 81c5b42875..71e6cbb388 100644
> --- a/git-rebase--interactive.sh
> +++ b/git-rebase--interactive.sh
> @@ -921,15 +921,20 @@ else
>  
>  		if test -z "$rebase_root"
>  		then
>  			preserve=t
> +			p=
>  			for p in $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)
>  			do
>  				if test -f "$rewritten"/$p
>  				then
>  					preserve=f
>  				fi
>  			done
> +			if test -z "$p"
> +			then
> +				preserve=f
> +			fi
>  		else
>  			preserve=f
>  		fi
>  		if test f = "$preserve"
> 
> Because it at least adds "two" to the list of commits to pick. But
> oddly, it picks it directly as a root commit again. Whereas a rebase
> without --preserve-merges (and even "-i") picks it on top of commit
> "one" (which is what I'd expect).
> 
> +cc Dscho, as the --preserve-merges guru.

Your analysis makes sense to me. Please note, though, that I would not consider myself a guru on preserve-merges. I think this mode is broken by design (you can blame me if you want).

Ciao, Dscho

Previous: Jeff KingNext: Jeff King
Message 5 of 8 in “[BUG] [git 2.16.1] yeeek ... my files are gone .. by git pull <otherRepositoryUrl>”
  1. Marcel 'childNo͡.de' TrautweinFeb 22, 2018
  2. Jonathan NiederFeb 22, 2018
  3. Marcel 'childNo͡.de' TrautweinFeb 23, 2018
  4. Jeff KingFeb 23, 2018
  5. Johannes SchindelinFeb 26, 2018
  6. Jeff KingFeb 28, 2018
  7. Johannes SchindelinMar 5, 2018
  8. Jeff KingMar 5, 2018

Read the whole thread, see it on lore, or plain text.

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