Re: [Monotone-devel] Problems with _MTN/tmp

[Nathaniel Smith]

On Wed, May 31, 2006 at 09:28:50AM +0100, Ian France wrote:
> >I bet this error is easy to reproduce as:
> >  -- put some unknown or ignored file inside a directory
> >  -- update to a revision in which that directory has been removed
> >
> 
> Ah, yes. That seems to do it very effectively. Interestingly the newly 
> added file _is_ deleted in the workspace. It seems to be a problem in 
> the _MTN/tmp directory rather than in the workspace.

Technically, it isn't deleted, it's just moved to _MTN/tmp :-)

The exact sequence of events is:
  -- mtn decides that directory 'foo' should go
  -- mtn moves that directory to _MTN/tmp, like 'mv foo _MTN/tmp/7'
     this works fine, renaming doesn't care if a directory has stuff
     in it
  -- mtn deletes that directory from _MNT/tmp, like 'rmdir _MTN/tmp/7'
     oops, this step fails, because _MTN/tmp/7 (formerly known as
     'foo') is not empty
  -- mtn waves its hands in the air and gives up

> Also, the tmp directory is not cleared up after the failure, nor when 
> the next command using it is run.

Right.  This is sort-of intentional, we don't have any robust
mechanism for dealing with all these corner cases, so we just sort of
default to never deleting anything -- on the theory that if we're
going to do something totally stupid anyway, it's better to be stupid
in a way that requires user intervention than to be stupid in a way
that silently deletes(!) data.

Really we need a better and more systematic way to deal with these
sorts of issues, though.  Probably it should be some sort of conflict?
It's not too unlike the "orphaned file" conflict case...

-- Nathaniel

-- 
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