Failed integrity check during merge

[Matt Mackall]

On Thu, 2012-09-20 at 10:54 +0200, Michał Sznajder wrote:
> I was surprised today a little bit. One of my coworkers tried to make
> a merge from
> default to feature branch and got
> 
> abort: integrity check failed on data/SomeDir/SomeFile.mdb.i:1!
> [command returned code 255 Wed Sep 19 13:54:43 2012]
> 
> File is a big binary blob (~4 Mb) so my warning sign started to blink.
> We tried hg verify and all looked OK. Then we tried merge branch
> to default and it worked. Then we tried again original merge and it
> went through.
> 
> We are on Windows, latest hg (2.3.1). Any idea? Hostile virus scanner?

If you're not on server-class hardware with ECC, I'd say it's a hardware
memory error. Modern PCs have somewhere on the order of one a day to one
a week, most of which have no visible effect.

For the curious, the best paper on the subject is probably:

www.cs.utoronto.ca/~bianca/papers/sigmetrics09.pdf

-- 
Mathematics is the supreme nostalgia of our time.