[RFE/RFC] format-patch/diff via path

I’m still a bit perplexed by some behaviour seen today, and am looking for a clean way to deal with it that the documentation does not make clear. So, I’m asking in a different way. Suppose a graph of

A---B---C---D---E
\      \               /
  \----F—G----/

When trying to perform a format-patch from B to E, I was seeing commits B-A-F-G-E rather than what I wanted B-C-D-E.  F and G were younger commits than C and D, which I assume (very likely wrongly) is why diff was giving preferential treatment to that path.

What I am trying to figure out is whether there is a clean way to force format-patch along the B-C-D-E path. If not, would it be worth starting up a small project to make this possible (not knowing exactly where to start), but I would envision something like: git format-patch –via=C B..E

I may be just missing something obvious (new to format-patch operations myself). 

Cheers, Randall P.S. Bad ideas happen when tests run for a long time 😉

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