Checkout files not in sync with workdir parent !

[Matt Mackall]

On Tue, 2013-01-08 at 14:48 -0500, Long Vu wrote:

>         It may also be possible to miss changes if a write to the file
>         occurs
>         during checkout.
> 
> Interesting !  Do you mean if another process write to the file during
> checkout, checkout will fail to update that file but still think the
> file is clean?

No, Mercurial will succeed in updating the file.. but there's absolutely
nothing to prevent another process to scribble on it afterwards or even
during that update.

Mercurial has no choice but presume it succeeded if it didn't encounter
an error. Checking the result is expensive and suffers the same problem:
the file can be changed between the time you start checking and the time
you conclude it's correct. Infinite regress.

So we can't fix this and we won't waste any effort trying. If you're
writing to tracked files while you're checking them out, you have Much
Bigger Problems™ anyway.

-- 
Mathematics is the supreme nostalgia of our time.