disappearing repo history on samba server

Adrian Buehlmann adrian at cadifra.com
Tue Dec 7 14:42:14 CST 2010


On 2010-12-07 20:38, Joel B. Mohler wrote:
> Hi,  My windows machines have been having a rocky relationship with 
> their samba server.  The latest issue is that a push to a certain 
> repository will wipe out revision history.  I've narrowed this down to a 
> very small slice of mercurial code which has nothing at all to do with 
> the changeset index, but the symptom with-in mercurial is that 
> .hg\store\00changelog.i is renamed to .hg\store\00changelog.i.hgtmp and 
> then my repository history is effectively wiped out (although the exact 
> details of what goes on with 00changelog.i.hgtmp appear to vary somewhat 
> by windows client machine).
> 
> The fatal bug is reproduced by the python script at
>      http://kiwistrawberry.us/opener.py
> This script assumes that you have mercurial and python win32 extensions 
> installed on a windows machine.  Without python win32 extensions, the 
> windows link code goes into graceful (?) degradation mode and so the 
> faulty code is not run.  The bug reproduces with two different windows 
> machines (vista and server 2008) and two different linux servers (ubuntu 
> and gentoo) so I'm quite confident it's not just a server configuration 
> fluke.
> 
> However, there's a weird gotcha which I don't understand yet.  It is 
> that I can only reproduce this on a large repository of about 32000 
> revisions which I can't make public.  Attempts on a smaller repository 
> have all worked (i.e. reproducing the bug failed).  From my opener.py 
> script, I come to the conclusion that for some reason 00changelog.i is 
> held open longer for a larger repository, but I was unable to determine 
> why that might be.
> 
> All relevant mercurial installs are at least 1.7.1 and I don't see any 
> evidence that variations of revision beyond the arrival of the 
> checknlink function make any difference.
> 
> So, two questions:
> 1)  Am I correct in believing that opener.py illustrates potential for a 
> data-losing bug?
> 2)  Is more information needed about my repository or can a fix for 
> opener.py be found with-out that?
> 

Thanks for your http://kiwistrawberry.us/opener.py script, I'll take a
closer look.

Known evil Windows things found so far:
http://mercurial.selenic.com/wiki/UnlinkingFilesOnWindows
http://mercurial.selenic.com/bts/issue2524

(as discussed on IRC)


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