llvm dev - Nov 2012 - [LLVMdev] svn mirror git?

David Chisnall <David.Chisnall at cl.cam.ac.uk> writes:
> clock skew (which is easy to get in a VM) can confuse Ninja in a way
> that doesn't give helpful errors.
This is a significant issue.  I would not want to transition to
cmake+ninja before this is fixed.

                             -David

>> clock skew (which is easy to get in a VM) can confuse Ninja in a way
>> that doesn't give helpful errors.
>
>This is a significant issue.  I would not want to transition to
>cmake+ninja before this is fixed.
Do you mean in the same way that clock skew would affect Make?  Or just
that Ninja doesn't provide that nice "clock skew detected" message
that
Make does?  Or are you looking for a build system that uses file hashes
instead of last-modified times?

> I think svn works better than git as an authoritative upstream
Would you mind expanding on this?  What problem specifically is being
solved?  Linus and Guido both use DVCS's and the authoritative upstream is
whatever URL the BDFL says it is.

Thanks,
Greg



On Thu, Nov 15, 2012 at 9:38 AM, <dag at cray.com> wrote:
> David Chisnall <David.Chisnall at cl.cam.ac.uk> writes:
>
> > clock skew (which is easy to get in a VM) can confuse Ninja in a way
> > that doesn't give helpful errors.
>
> This is a significant issue.  I would not want to transition to
> cmake+ninja before this is fixed.
>
>                              -David
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
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On 15 Nov 2012, at 10:40, Greg Fitzgerald wrote:
> Do you mean in the same way that clock skew would affect Make?  Or just
that Ninja doesn't provide that nice "clock skew detected" message
that Make does?  Or are you looking for a build system that uses file hashes
instead of last-modified times?
Ninja complains about circular dependencies when you have your clock set to the
wrong time.  There is no easy way of fixing this other than to delete the entire
build tree and start again.
> > I think svn works better than git as an authoritative upstream
> 
> Would you mind expanding on this?  What problem specifically is being
solved?  Linus and Guido both use DVCS's and the authoritative upstream is
whatever URL the BDFL says it is.
Monotonic version numbers are the biggest advantage.  It is easy to see that
r1234432 contains the bug fix introduced in r1234430. It is very hard to see if
version 23bef194ac contains the bug fix added in 23bef19412.  This makes
interaction with bugzilla and so on much easier.  If someone says 'please
test r1245145 - should be fixed' you can easily check whether you are
running r1245145 or newer.

David