[eqvinox]

I think there's a confusion here between diffs and patches. I would call the thing you're describing a patch, not a diff, and then everything makes much more sense.

(This is not helped by the fact that diffs often come with a .patch file extension… or that the "patch" tool processes diffs…)

Or anyway the nomenclature really sucks in this field. I guess I have no clue whether I have a minority view here.

[chipx86]

Yeah the nomenclature sucks.

When talking about the file, the two terms are often used interchangeably (and are usually a .diff or a .patch extension).

For fun, the GNU Patch manpage says:

"NAME: patch - apply a diff file to an original"

followed by:

"patch takes a patch file patchfile containing ..."

"patch tries to skip any leading garbage, apply the diff, and then ..."