[PATCH] dim: Add range-diff convenience wrapper

[Daniel Vetter]

range-diff is awesome, but the interface is a bit silly. Add a bunch
of shortcuts, inspired by what git diff does.

v2: Add it to the developer commmands list. With this dim range-diff
is useable on any git repo, not just a dim managed one.

v3: Comments from Lucas:
- Forward additional arguments. There's no --no-patch in upstream git,
  but I tested this with --no-color and --no-dual-color. Slightly a
  hack since detecting whether it's a branch or not became even more
  fun, but works in all cases.
- Remove impossible "$branch" == "" check - I added a default.

Cc: Lucas De Marchi <lucas.de.marchi at gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 dim     | 19 +++++++++++++++++++
 dim.rst |  8 ++++++++
 2 files changed, 27 insertions(+)

diff --git a/dim b/dim
index 72c86db560a7..aeaea05dac4b 100755
--- a/dim
+++ b/dim
@@ -475,6 +475,24 @@ function dim_retip
 	git rebase --onto $new_upstream $upstream $branch "$@"
 }
 
+function dim_range_diff
+{
+	local branch
+
+	branch=${1:-@\{1\}}
+
+	if [[ $(git rev-parse $branch | wc -l) -eq 1 ]] ; then
+		if [[ $(git rev-parse $branch) == "$branch" ]] ; then
+			branch="@{1}"
+		else
+			shift || true
+		fi
+		git range-diff $branch...HEAD "$@"
+	else
+		git range-diff "$@"
+	fi
+}
+
 # update for-linux-next and for-linux-next-fixes branches
 function update_linux_next # branch next next-fixes fixes
 {
@@ -2190,6 +2208,7 @@ function list_developer_commands
 		"cite"
 		"fixes"
 		"retip"
+		"range-diff"
 		"sparse"
 		"tc"
 		# help commands
diff --git a/dim.rst b/dim.rst
index b149fa39445e..9e41133aeb8d 100644
--- a/dim.rst
+++ b/dim.rst
@@ -95,6 +95,14 @@ retip [*branch*] [*git-rebase option* ...]
 Rebase the given local branch, current branch by default, onto drm-tip. Options
 after the branch will be passed to **git-rebase**.
 
+range-diff [ *commit-ish* | *git-range-diff options* ]
+------------------------------------------------------
+
+Convenience wrapper around the git range-diff command which automatically
+compares against HEAD if you only specify a commit-ish. In all other cases
+forwards to git range-diff. Defaults to @{1}, which is very useful for reviewing
+rebases.
+
 COMMANDS FOR COMMITTERS AND MAINTAINERS
 =======================================
 
-- 
2.19.0.rc2