hg diff takes 30 seconds to find nothing.

[Matt Mackall]

On Wed, Dec 06, 2006 at 07:59:48PM -0500, Rob Landley wrote:
> Why does "hg diff" do the equivalent of a "find ." in the repository 
> directory, rather than just looking at the manifest to get its file list?
> 
> My source directory has a "build" directory generated under it when I do test 
> builds, and this has tens of thousands of files in it (extracted tarballs, 
> etc), and doing an "hg diff" in this directory with a clean cache can take 
> over 30 seconds to tell me that nothing it's tracking actually changed.
> 
> I did an strace -f of hg (0.9.1), and sure enough it's looking at files that 
> have never been checked in.  Why is it even bothering to look at files that 
> aren't in the manifest?  Can there possibly be differences between them?

No good reason. It uses basically the same code path that commit does.

You probably want to add build/ to your .hgignore and then both diff
and commit will be fast again.

-- 
Mathematics is the supreme nostalgia of our time.