Help! Git disaster!

Thu Apr 14 17:52:30 CEST 2011

I'm resetting the remote repo. Please stand by.

Cheers,
Edward

Excerpts from Johan Tibell's message of Thu Apr 14 11:46:33 -0400 2011:
> Hi,
> 
> On Thu, Apr 14, 2011 at 5:33 PM, Simon Peyton-Jones
> <simonpj at microsoft.com> wrote:
> > Oh *bother*.  I have no clue how this happened but I appear to have merged ghc-generics into the HEAD.  I certainly did not intend to do so.  ghc-generics is supposed to be a separate branch, and to stay that way till it works.
> >
> > Oh... looking back I did try to update my ghc-generics branch by saying
> >        git pull origin ghc-generics
> > but it appears that it updated my master branch with the remote ghc-generics branch.  Sigh.
> >
> > Regardless of how I managed to do this, it's still going to screw everyone else up.  Having merged it into HEAD I have no idea how to un-merge it again.  Any attempt to do so will probably just make matters worse.   Help!   Can someone (Simon? Ian? Max?  but probably only one of you) undo my mischief?
> >
> >        I apologise humbly.
> >
> > I did ask myself the question "what will 'push' do", but I was unable to find out.
> >        git push --dry-run
> > was uninformative.
> 
> DON'T PANIC (written with big bold friendly letters)
> 
> See http://www.kernel.org/pub/software/scm/git/docs/howto/revert-a-faulty-merge.txt
> 
> If you give me a few minutes I'll try to figure out an exact command
> sequence you can run.
> 
> Aside
> =====
> 
> If you hadn't pushed the change yet you could use git's reflog to go
> back to any point before you got your repo into a mess. The reflog is
> the linear history of changes you have applied to your local
> repository (~the history effecting commands you have run). Here's how
> you use it:
> 
> $ git reflog
> 971621b HEAD@{0}: pull --rebase: Add array copy/clone primops
> 25297a1 HEAD@{1}: checkout: moving from master to
> 25297a13bd6be722a74ee87237498a5626b298ef^0
> 09437c3 HEAD@{2}: pull --rebase: Add array copy/clone primops
> 592b33e HEAD@{3}: checkout: moving from master to
> 592b33e265756d6b9ce156d53f187090366ae29b^0
> 
> If I wanted to go back in time to before I ran pull --rebase the last
> time I would do:
> 
> $ git reset --hard HEAD@{1}, which would discard the very last change
> I did to the repo.
> 
> The reflog makes it hard to actually damage your local repository, no
> matter what you do. The reflog works because commits are never really
> lost (except for when you run git gc), they are merely not referred to
> by any named reference (e.g. HEAD, master, my-branch, etc) anymore.
> The reflog still keeps track of the commits SHA-1 and thus git can
> find the commit again.
> 
> >
> >
> > Simon
> >
> > -----Original Message-----
> > From: cvs-ghc-bounces at haskell.org [mailto:cvs-ghc-bounces at haskell.org] On Behalf Of Simon Peyton Jones
> > Sent: 14 April 2011 16:22
> > To: cvs-ghc at haskell.org
> > Subject: [commit: ghc] master: Merge branch 'ghc-generics' of http://darcs.haskell.org/ghc (5305c38)
> >
> > Repository : ssh://darcs.haskell.org//srv/darcs/ghc
> >
> > On branch  : master
> >
> > http://hackage.haskell.org/trac/ghc/changeset/5305c38484cccf341e761e05614d414cd77dfec9
> >
> >>---------------------------------------------------------------
> >
> > commit 5305c38484cccf341e761e05614d414cd77dfec9
> > Merge: 2c618c2... ce2ea82...
> > Author: unknown <simonpj at .europe.corp.microsoft.com>
> > Date:   Thu Apr 14 16:15:10 2011 +0100
> >
> >    Merge branch 'ghc-generics' of http://darcs.haskell.org/ghc
> >
> >  compiler/basicTypes/OccName.lhs     |   26 ++-
> >  compiler/deSugar/DsMeta.hs          |    1 +
> >  compiler/hsSyn/HsBinds.lhs          |   28 ++-
> >  compiler/hsSyn/HsUtils.lhs          |    2 +-
> >  compiler/iface/BuildTyCl.lhs        |    8 +-
> >  compiler/iface/MkIface.lhs          |    6 +-
> >  compiler/main/HscStats.lhs          |   22 +-
> >  compiler/parser/Lexer.x             |    4 +-
> >  compiler/parser/Parser.y.pp         |   11 +-
> >  compiler/parser/RdrHsSyn.lhs        |   13 +-
> >  compiler/prelude/PrelNames.lhs      |  161 +++++++++++-
> >  compiler/rename/RnBinds.lhs         |   24 ++-
> >  compiler/rename/RnHsSyn.lhs         |    9 +-
> >  compiler/rename/RnSource.lhs        |   11 -
> >  compiler/typecheck/TcClassDcl.lhs   |  222 +++++++---------
> >  compiler/typecheck/TcDeriv.lhs      |  165 +++++++++++-
> >  compiler/typecheck/TcEnv.lhs        |    6 +-
> >  compiler/typecheck/TcGenDeriv.lhs   |    2 +-
> >  compiler/typecheck/TcInstDcls.lhs   |   21 ++-
> >  compiler/typecheck/TcRnDriver.lhs   |    9 +-
> >  compiler/typecheck/TcTyClsDecls.lhs |   23 ++-
> >  compiler/types/Class.lhs            |   10 +-
> >  compiler/types/Generics.lhs         |  502 ++++++++++++++++++++++++++---------
> >  compiler/types/TyCon.lhs            |    7 +-
> >  compiler/types/Type.lhs             |    6 +-
> >  25 files changed, 941 insertions(+), 358 deletions(-)
> >
> >
> >
> >
> > |  -----Original Message-----
> > |  From: cvs-ghc-bounces at haskell.org [mailto:cvs-ghc-bounces at haskell.org] On Behalf
> > |  Of Simon Peyton Jones
> > |  Sent: 14 April 2011 16:22
> > |  To: cvs-ghc at haskell.org
> > |  Subject: [commit: ghc] master's head updated: Merge branch 'ghc-generics' of
> > |  http://darcs.haskell.org/ghc (5305c38)
> > |
> > |  Repository : ssh://darcs.haskell.org//srv/darcs/ghc
> > |
> > |  Branch 'master' now includes:
> > |
> > |       2a26efb... Initial commit for Pedro's new generic default methods (See his Haskell
> > |  Symposium 2010 paper     "A generic deriving mechaism for Haskell")
> > |       83f16ad... Adapt mkGenericDefMethBind to the new generics
> > |       8419203... Merge branch 'master' of c:/code/HEAD-git/. into ghc-generics
> > |       2fcc09a... Minor refactoring of Max's patch for #4404
> > |       27fc7ca... Merge branch 'master' of http://darcs.haskell.org/ghc
> > |       ce2ea82... Small fixes to the generics branch to get rid of warnings, plus a false
> > |  ASSERT failure
> > |       2c618c2... Merge branch 'master' of http://darcs.haskell.org/ghc
> > |       5305c38... Merge branch 'ghc-generics' of http://darcs.haskell.org/ghc
> > |
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> >
> >
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