Bulk move and some of its close relatives

On Mon, Oct 25, 2010 at 10:12:27PM +0200, Yann Dirson wrote:

I had a couple of thoughts about this dir-rename -> bulk-moves shift today while riding to/from work. So here are some of the fresh air I got...

Is a bulk-move finally so special ? There is a close relative to it which may be of interest too: bulk deletion. If we implement detection of bulk deletion, we can build on it to get:

* detection of a new type of conflict: addition in a branch of a new
  file in a dir which is deleted in the other branch (quite similar to
  the one we were talking about, of a new file in a dir that got moved in
  other branch)
* split a good part of the current bulk-move patch in a standalone
  patch, which is something I wondered how to do
* probably a much better base for directory-split detection

Then, since a bulk-move is made of a bulk deletion, and addition somewhere else of those deleted files, it became tempting to contemplate the concept of "bulk addition". At first sight it seems awkward, I confess, especially "bulk addition into a preexisting dir", which is a bit hard to define with precision. OTOH, "bulk addition of a brand new dir" could bring goodies as well:

* new conflict type: creation in both branches of a new directory with
  same name

That confict type made me think of another one. Some of you may have noticed in the v7 commit message a suggestion for future developments labelled "support other types of bluk-grouping, like prefixes, and maybe config-specified patterns". Now if we get the capability of specifying how we define a "group of files" with something other than the directory hierarchy (let's say eg. that in t/ every "t[0-9]{4}-" is a prefix), the "bulk-add/bulk-add" conflict generated by 2 tests with same numeric ID would be detected as a conflict.

Another grouping example would be by file suffix - source-code reorgs eg. bulk-moving header files into their own dir are not rare either.

Does that sound sane ?