RFE: download patch between arbitrary revisions

[Lukas Fleischer]

On Sun, Jun 16, 2013 at 11:11:22AM +0100, John Keeping wrote:
> On Sun, Jun 16, 2013 at 09:56:55AM +0200, Lukas Fleischer wrote:
> > On Thu, Jun 13, 2013 at 11:21:26PM +0100, John Keeping wrote:
> > > On Thu, Jun 13, 2013 at 11:58:10PM +0200, Lukas Fleischer wrote:
> > > > On Mon, Jun 03, 2013 at 07:49:53PM +0100, John Keeping wrote:
> > > > > On Sun, Jun 02, 2013 at 09:19:11PM -0400, Konstantin Ryabitsev wrote:
> > > > > > There is currently a way to render a diff between two arbitrary objects,
> > > > > > e.g.:
> > > > > > 
> > > > > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/diff/?id=v3.10-rc4&id2=v3.10-rc3
> > > > > > 
> > > > > > However, there doesn't appear to be a way to download a patch in the
> > > > > > same way -- it will only make patch against id's parent. E.g.:
> > > > > > 
> > > > > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/patch/?id=v3.10-rc4&id2=v3.10-rc3
> > > > > > 
> > > > > > Any way we can make the behaviour of patch match that of diff?
> > > > > 
> > > [...]
> > > 
> > > So:
> > > 
> > >     /patch/?id=v1.8.3.1&id2=v1.8.3
> > > 
> > > generates something like "git format-patch v1.8.3..v1.8.3.1".  And
> > > 
> > >     /rawdiff/?id=v1.8.3.1&id2=v1.8.3
> > > 
> > > generates the diff with no HTML around it.
> > > 
> > > The latter could be a query parameter instead ("raw=1"?).  Having not
> > > investigated the impact on the code, I have no preference for one over
> > > the other.
> > 
> > Sounds good to me either way. Jason?
> > 
> > Also, I just wondered whether this could be used to DoS servers when
> > requesting a series of patches for a huge range of revisions... Maybe
> > there should be some kind of limit?
> 
> The "diff" version costs about the same regardless of how many revisions
> are between the endpoints - it's purely a function of the size of the
> tree (and the number of changed files which probably is affected by how
> far apart the commits are, but it's still bounded by the size of the
> tree).
> 
> I can see it potentially being a problem in the "format-patch" case, so
> perhaps we want to add a "max-patches-per-request" variable if we do
> implement that.

Yeah, the `git format-patch` case is what I meant with "requesting a
series of patches". Limiting the number of patches also sounds good to
me.

I will go ahead and implement this if Jason likes the idea :)