From 3d810726afcd53590f28fa7fcb8b4c649ae6b7c3 Mon Sep 17 00:00:00 2001
From: Joey Hess <joeyh@joeyh.name>
Date: Wed, 5 Jul 2023 15:43:29 -0400
Subject: [PATCH] diffdriver --text support options for diff

Sponsored-by: KDM on Patreon
---
 Command/DiffDriver.hs                     | 12 +++++++-----
 doc/git-annex-diffdriver.mdwn             |  3 ++-
 doc/todo/Improving_diffdriver_--text.mdwn |  2 ++
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/Command/DiffDriver.hs b/Command/DiffDriver.hs
index c63994d8ab..d4057763ac 100644
--- a/Command/DiffDriver.hs
+++ b/Command/DiffDriver.hs
@@ -70,7 +70,9 @@ serializeReq req@(Req {}) = map Param
 
 parseReq :: Options -> (Req, Differ)
 parseReq opts
-	| textDiff opts = (mk (restOptions opts), textDiffer)
+	| textDiff opts = case separate (== "--") (restOptions opts) of
+		(_,[]) -> (mk (restOptions opts), textDiffer [])
+		(ps,rest) -> (mk rest, textDiffer ps)
 	| otherwise = case separate (== "--") (restOptions opts) of
 		(c:ps, l) -> (mk l, externalDiffer c ps)
 		([],_) -> badopts
@@ -117,13 +119,13 @@ fixupReq req@(Req {}) =
 externalDiffer :: String -> [String] -> Differ
 externalDiffer c ps = \req -> boolSystem c (map Param ps ++ serializeReq req )
 
-textDiffer :: Differ
-textDiffer req = do
+textDiffer :: [String] -> Differ
+textDiffer diffopts req = do
 	putStrLn ("diff a/" ++ rPath req ++ " b/" ++ rPath req)
 	-- diff exits nonzero on difference, so ignore exit status
-	void $ boolSystem "diff"
+	void $ boolSystem "diff" $
 		[ Param "-u"
 		, Param (rOldFile req)
 		, Param (rNewFile req)
-		]
+		] ++ map Param diffopts
 	return True
diff --git a/doc/git-annex-diffdriver.mdwn b/doc/git-annex-diffdriver.mdwn
index f0915b0de2..c2c2537cf5 100644
--- a/doc/git-annex-diffdriver.mdwn
+++ b/doc/git-annex-diffdriver.mdwn
@@ -4,7 +4,7 @@ git-annex diffdriver - git diff driver
 
 # SYNOPSIS
 
-git annex diffdriver --text
+git annex diffdriver --text [-- --opts --]
 
 git annex diffdriver `-- cmd --opts --`
 
@@ -42,6 +42,7 @@ set `GIT_EXTERNAL_DIFF="git-annex diffdriver -- j-c-diff --"`
 # OPTIONS
 
 To diff text files with diff(1), use the "--text" option.
+To pass additional options to diff(1), use eg "--text -- --color --"
 
 To use an external diff driver command, the options must start with
 "--" followed by the diff driver command, its options, and another "--"
diff --git a/doc/todo/Improving_diffdriver_--text.mdwn b/doc/todo/Improving_diffdriver_--text.mdwn
index 36423d5aed..4ad12ff20c 100644
--- a/doc/todo/Improving_diffdriver_--text.mdwn
+++ b/doc/todo/Improving_diffdriver_--text.mdwn
@@ -28,3 +28,5 @@ How about having `git annex diffdriver --text` always using `diff --text`? That
 Thanks again a ton for git-annex, the Tübix2023-Workshop was well appreciated and lots of fun. 👍
 
 Yann
+
+> [[done]] --[[Joey]]