range-diff: relieve callers of low-level configuration burden

diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index b41e1329a7d8439762790e663ac52ec5f487bc8b..f8a061794dcabc1b54a2e17dbfc178b5ce25caf9 100644 (file)
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -23,6 +23,7 @@ SYNOPSIS
                   [(--reroll-count|-v) <n>]
                   [--to=<email>] [--cc=<email>]
                   [--[no-]cover-letter] [--quiet] [--notes[=<ref>]]
+                  [--interdiff=<previous>]
                   [--progress]
                   [<common diff options>]
                   [ <since> | <revision range> ]
@@ -228,6 +229,15 @@ feeding the result to `git send-email`.
        containing the branch description, shortlog and the overall diffstat.  You can
        fill in a description in the file before sending it out.
 
+--interdiff=<previous>::
+       As a reviewer aid, insert an interdiff into the cover letter,
+       or as commentary of the lone patch of a 1-patch series, showing
+       the differences between the previous version of the patch series and
+       the series currently being formatted. `previous` is a single revision
+       naming the tip of the previous series which shares a common base with
+       the series being formatted (for example `git format-patch
+       --cover-letter --interdiff=feature/v1 -3 feature/v2`).
+
 --notes[=<ref>]::
        Append the notes (see linkgit:git-notes[1]) for the commit
        after the three-dash line.