RE: [PATCH v2] Enable auto-merge for meld to follow the vim-diff beharior

[<lin.sun@zoom.us>]

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Hi Danh,

> It seems like only David Aguilar (Cc-ed) works on that file.
>Look into  b12d04503b (mergetools/meld: make usage of `--output` configurable and more robust, 2014-10-15), it looks like we need to check if --auto-merge option is available in meld.
>Someone still live with the ancient tools ;).
>meld has known --output for a long time but we still have a check for it.

Thank you for your hints, I changed the patch for checking the option "--auto-merge" in meld and use this option only if it's available.
The last patch is appended in attachment, or https://github.com/git/git/commit/3b70fd0bfc4086a08e27c869ff7492d567e8fdc2

Look forward it can be merged this time. 
Thanks

Regards
Lin

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From 3b70fd0bfc4086a08e27c869ff7492d567e8fdc2 Mon Sep 17 00:00:00 2001
From: "lin.sun" <lin.sun@zoom.us>
Date: Thu, 7 May 2020 07:31:14 +0800
Subject: [PATCH] Enable auto-merge for meld to follow the vim-diff beharior

The mergetool "meld" does NOT merge the no-conflict changes, while the
mergetool "vimdiff" will merge the no-conflict parts and highlight the
conflict parts.
This patch will make the mergetool "meld" similar to "vimdiff",
auto-merge the no-conflict parts, highlight conflict parts.

Signed-off-by: Lin Sun <lin.sun@zoom.us>
---
 mergetools/meld | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/mergetools/meld b/mergetools/meld
index 7a08470..91b65ff 100644
--- a/mergetools/meld
+++ b/mergetools/meld
@@ -7,13 +7,23 @@ merge_cmd () {
 	then
 		check_meld_for_output_version
 	fi
+	if test -z "${meld_has_auto_merge_option:+set}"
+	then
+		check_meld_for_auto_merge_version
+	fi
+
+	option_auto_merge=
+	if test "$meld_has_auto_merge_option" = true
+	then
+		option_auto_merge="--auto-merge"
+	fi
 
 	if test "$meld_has_output_option" = true
 	then
-		"$merge_tool_path" --output="$MERGED" \
+		"$merge_tool_path" $option_auto_merge --output="$MERGED" \
 			"$LOCAL" "$BASE" "$REMOTE"
 	else
-		"$merge_tool_path" "$LOCAL" "$MERGED" "$REMOTE"
+		"$merge_tool_path" $option_auto_merge "$LOCAL" "$MERGED" "$REMOTE"
 	fi
 }
 
@@ -34,3 +44,21 @@ check_meld_for_output_version () {
 		meld_has_output_option=false
 	fi
 }
+
+# Check whether we should use 'meld --auto-merge ...'
+check_meld_for_auto_merge_version () {
+	meld_path="$(git config mergetool.meld.path)"
+	meld_path="${meld_path:-meld}"
+
+	if meld_has_auto_merge_option=$(git config --bool mergetool.meld.hasAutoMerge)
+	then
+		: use configured value
+	elif "$meld_path" --help 2>&1 |
+		grep -e '--auto-merge' -e '\[OPTION\.\.\.\]' >/dev/null
+	then
+		: old ones mention --auto-merge and new ones just say OPTION...
+		meld_has_auto_merge_option=true
+	else
+		meld_has_auto_merge_option=false
+	fi
+}
-- 
2.2.0