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

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 20, 2018, 07:14 UTC
Message-ID: <xmqqinbxngra.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <018601d391b7$8e8686a0$ab9393e0$@nexbridge.com>

"Randall S. Becker" <rsbecker@nexbridge.com> writes:

Show 6 quoted lines

> 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----/
>

An ASCII art that is not drawn for fixed-width font is by definition understandable only by the person who drew it X-<. I am guessing that F is a child of both A and B (but I am not sure, as I do not see a reason why it should even be a merge to begin with, so my guess is likely to be wrong), and E is a merge between D and G.

IOW, I am guessing that the below is the equivalent of what you drew for those who look at the picture in fixed-width font:

    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.

Assuming that E is a merge, format-patch output should not show E anyway (i.e. think in terms of "git log --no-merges --reverse", instead of fearing that format-patch is somehow more magical---it is not). So if you want to show the comit B, C and D (meaning three patches, i.e. "diff A B", "diff B C", and "diff C D"), then you would do "format-patch A..D", not "format-patch A..E". If you meant that you are not interested in the change between A and B, then the range would be "B..D" instead of "A..D". Ending the range at "E" means you want to see what is reachable from E, and unless you say you are not interested in G, you would get G, if you only say you are not interested in A (or B), as G is not reachable from A (or B).

It is unclear how you told format-patch when "trying to perform a format-patch from B to E" from your description, but if you said "format-patch A^..E", it is likely that you would have seen all commits in the depicted part of the graph except for merge commits.