RE: [PATCH v3] Enable auto-merge for meld to follow the vim-diff beharior

[<lin.sun@zoom.us>]

[-- Attachment #1: Type: text/plain, Size: 358 bytes --]

Hi David, Junio,

Appreciate for your comments, I rewrite the "mergetool/meld" to follow your comments and suggestions.
It will respect the git config first, then detect the options if no configuration for them, and also reduce the subprocess calling.
Both the modified-file and patch-file are appended.
Please review again. Thanks

Regards
Lin Sun

[-- Attachment #2: 0001-Enable-auto-merge-for-meld-to-follow-the-vim-diff-be.patch --]
[-- Type: application/octet-stream, Size: 3503 bytes --]

From 93ae3ec011e7b55cc9971f91345cb4aab5189cb4 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

Make the mergetool used with "meld" backend behave similarly to
how "vimdiff" beheaves by telling it to auto-merge parts without
conflicts and highlight the parts with conflicts.

Signed-off-by: lin.sun <lin.sun@zoom.us>
---
 mergetools/meld | 73 ++++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 57 insertions(+), 16 deletions(-)

diff --git a/mergetools/meld b/mergetools/meld
index 7a08470..1b92771 100644
--- a/mergetools/meld
+++ b/mergetools/meld
@@ -3,34 +3,75 @@ diff_cmd () {
 }
 
 merge_cmd () {
-	if test -z "${meld_has_output_option:+set}"
+	check_meld_for_features
+
+	option_auto_merge=
+	if test "$meld_has_auto_merge_option" = true
 	then
-		check_meld_for_output_version
+		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
 }
 
-# Check whether we should use 'meld --output <file>'
-check_meld_for_output_version () {
-	meld_path="$(git config mergetool.meld.path)"
-	meld_path="${meld_path:-meld}"
+# Get meld help message
+get_meld_help_msg () {
+	meld_path="$(git config mergetool.meld.path || echo meld)"
+  $meld_path --help 2>&1
+}
 
-	if meld_has_output_option=$(git config --bool mergetool.meld.hasOutput)
+# Check the features and set flags
+check_meld_for_features () {
+	# Check whether we should use 'meld --output <file>'
+	if test -z "${meld_has_output_option:+set}"
 	then
-		: use configured value
-	elif "$meld_path" --help 2>&1 |
-		grep -e '--output=' -e '\[OPTION\.\.\.\]' >/dev/null
+		meld_has_output_option=$(git config --bool mergetool.meld.hasOutput)
+		if test "$meld_has_output_option" = true -o \
+						"$meld_has_output_option" = false
+		then
+			: use configured value
+		else												# treat meld_has_output_option as "auto"
+			if test -z "$meld_help_msg"
+			then
+				meld_help_msg="$(get_meld_help_msg)"
+			fi
+
+			if echo "$meld_help_msg" |
+							grep -e '--output=' -e '\[OPTION\.\.\.\]' >/dev/null
+			then
+				: old ones mention --output and new ones just say OPTION...
+				meld_has_output_option=true
+			else
+				meld_has_output_option=false
+			fi
+		fi
+	fi
+	# Check whether we should use 'meld --auto-merge ...'
+	if test -z "${meld_has_auto_merge_option:+set}"
 	then
-		: old ones mention --output and new ones just say OPTION...
-		meld_has_output_option=true
-	else
-		meld_has_output_option=false
+		meld_has_auto_merge_option=$(git config --bool mergetool.meld.hasAutoMerge)
+		if test "$meld_has_auto_merge_option" = true -o \
+						"$meld_has_auto_merge_option" = false
+		then
+			: use configured value
+		else												# treat meld_has_auto_merge_option as "auto"
+			if test -z "$meld_help_msg"
+			then
+					meld_help_msg="$(get_meld_help_msg)"
+			fi
+
+			if echo "$meld_help_msg" | grep -e '--auto-merge' >/dev/null
+			then
+					meld_has_auto_merge_option=true
+			else
+				meld_has_auto_merge_option=false
+			fi
+		fi
 	fi
 }
-- 
2.2.0


[-- Attachment #3: meld --]
[-- Type: application/octet-stream, Size: 2038 bytes --]

diff_cmd () {
	"$merge_tool_path" "$LOCAL" "$REMOTE"
}

merge_cmd () {
	check_meld_for_features

	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" $option_auto_merge --output="$MERGED" \
			"$LOCAL" "$BASE" "$REMOTE"
	else
		"$merge_tool_path" $option_auto_merge "$LOCAL" "$MERGED" "$REMOTE"
	fi
}

# Get meld help message
get_meld_help_msg () {
	meld_path="$(git config mergetool.meld.path || echo meld)"
  $meld_path --help 2>&1
}

# Check the features and set flags
check_meld_for_features () {
	# Check whether we should use 'meld --output <file>'
	if test -z "${meld_has_output_option:+set}"
	then
		meld_has_output_option=$(git config --bool mergetool.meld.hasOutput)
		if test "$meld_has_output_option" = true -o \
						"$meld_has_output_option" = false
		then
			: use configured value
		else												# treat meld_has_output_option as "auto"
			if test -z "$meld_help_msg"
			then
				meld_help_msg="$(get_meld_help_msg)"
			fi

			if echo "$meld_help_msg" |
							grep -e '--output=' -e '\[OPTION\.\.\.\]' >/dev/null
			then
				: old ones mention --output and new ones just say OPTION...
				meld_has_output_option=true
			else
				meld_has_output_option=false
			fi
		fi
	fi
	# Check whether we should use 'meld --auto-merge ...'
	if test -z "${meld_has_auto_merge_option:+set}"
	then
		meld_has_auto_merge_option=$(git config --bool mergetool.meld.hasAutoMerge)
		if test "$meld_has_auto_merge_option" = true -o \
						"$meld_has_auto_merge_option" = false
		then
			: use configured value
		else												# treat meld_has_auto_merge_option as "auto"
			if test -z "$meld_help_msg"
			then
					meld_help_msg="$(get_meld_help_msg)"
			fi

			if echo "$meld_help_msg" | grep -e '--auto-merge' >/dev/null
			then
					meld_has_auto_merge_option=true
			else
				meld_has_auto_merge_option=false
			fi
		fi
	fi
}