mergetools: add description to all diff/merge tools

The output of `git mergetool --tool-help` and `git difftool --tool-help`
only showed the `alias` of each available merge/diff tool.

It is not always obvious what tool these `aliases` end up using (ex:
`opendiff` runs `FileMerge` and `bc` runs `Beyond Compare`).

This commit adds a short description to each of them to help the user
identify the `alias` they want.

Signed-off-by: Fernando Ramos <greenfoo@u92.eu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

mergetools/araxis

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" -wait -2 "$LOCAL" "$REMOTE" >/dev/null 2>&1
 }
 
+diff_cmd_help () {
+	echo "Use Araxis Merge (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -13,6 +17,10 @@ merge_cmd () {
 	fi
 }
 
+merge_cmd_help () {
+	echo "Use Araxis Merge (requires a graphical session)"
+}
+
 translate_merge_tool_path() {
 	echo compare
 }

mergetools/bc

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" "$LOCAL" "$REMOTE"
 }
 
+diff_cmd_help () {
+	echo "Use Beyond Compare (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -13,6 +17,10 @@ merge_cmd () {
 	fi
 }
 
+merge_cmd_help () {
+	echo "Use Beyond Compare (requires a graphical session)"
+}
+
 translate_merge_tool_path() {
 	if type bcomp >/dev/null 2>/dev/null
 	then

mergetools/codecompare

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" "$LOCAL" "$REMOTE"
 }
 
+diff_cmd_help () {
+	echo "Use Code Compare (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -13,6 +17,10 @@ merge_cmd () {
 	fi
 }
 
+merge_cmd_help () {
+	echo "Use Code Compare (requires a graphical session)"
+}
+
 translate_merge_tool_path() {
 	if merge_mode
 	then

mergetools/deltawalker

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" "$LOCAL" "$REMOTE" >/dev/null 2>&1
 }
 
+diff_cmd_help () {
+	echo "Use DeltaWalker (requires a graphical session)"
+}
+
 merge_cmd () {
 	# Adding $(pwd)/ in front of $MERGED should not be necessary.
 	# However without it, DeltaWalker (at least v1.9.8 on Windows)
@@ -16,6 +20,10 @@ merge_cmd () {
 	fi >/dev/null 2>&1
 }
 
+merge_cmd_help () {
+	echo "Use DeltaWalker (requires a graphical session)"
+}
+
 translate_merge_tool_path () {
 	echo DeltaWalker
 }

mergetools/diffmerge

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" "$LOCAL" "$REMOTE" >/dev/null 2>&1
 }
 
+diff_cmd_help () {
+	echo "Use DiffMerge (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -13,6 +17,10 @@ merge_cmd () {
 	fi
 }
 
+merge_cmd_help () {
+	echo "Use DiffMerge (requires a graphical session)"
+}
+
 exit_code_trustable () {
 	true
 }

mergetools/diffuse

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" "$LOCAL" "$REMOTE" | cat
 }
 
+diff_cmd_help () {
+	echo "Use Diffuse (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -13,3 +17,7 @@ merge_cmd () {
 			"$LOCAL" "$MERGED" "$REMOTE" | cat
 	fi
 }
+
+merge_cmd_help () {
+	echo "Use Diffuse (requires a graphical session)"
+}

mergetools/ecmerge

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" --default --mode=diff2 "$LOCAL" "$REMOTE"
 }
 
+diff_cmd_help () {
+	echo "Use ECMerge (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -12,3 +16,7 @@ merge_cmd () {
 			--default --mode=merge2 --to="$MERGED"
 	fi
 }
+
+merge_cmd_help () {
+	echo "Use ECMerge (requires a graphical session)"
+}

mergetools/emerge

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" -f emerge-files-command "$LOCAL" "$REMOTE"
 }
 
+diff_cmd_help () {
+	echo "Use Emacs' Emerge"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -17,6 +21,10 @@ merge_cmd () {
 	fi
 }
 
+merge_cmd_help () {
+	echo "Use Emacs' Emerge"
+}
+
 translate_merge_tool_path() {
 	echo emacs
 }

mergetools/examdiff

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" "$LOCAL" "$REMOTE" -nh
 }
 
+diff_cmd_help () {
+	echo "Use ExamDiff Pro (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -11,6 +15,10 @@ merge_cmd () {
 	fi
 }
 
+merge_cmd_help () {
+	echo "Use ExamDiff Pro (requires a graphical session)"
+}
+
 translate_merge_tool_path() {
 	mergetool_find_win32_cmd "ExamDiff.com" "ExamDiff Pro"
 }

mergetools/guiffy

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" "$LOCAL" "$REMOTE"
 }
 
+diff_cmd_help () {
+	echo "Use Guiffy's Diff Tool (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -13,6 +17,10 @@ merge_cmd () {
 	fi
 }
 
+merge_cmd_help () {
+	echo "Use Guiffy's Diff Tool (requires a graphical session)"
+}
+
 exit_code_trustable () {
 	true
 }

mergetools/kdiff3

@@ -4,6 +4,10 @@ diff_cmd () {
 		"$LOCAL" "$REMOTE" >/dev/null 2>&1
 }
 
+diff_cmd_help () {
+	echo "Use KDiff3 (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -22,6 +26,10 @@ merge_cmd () {
 	fi
 }
 
+merge_cmd_help () {
+	echo "Use KDiff3 (requires a graphical session)"
+}
+
 exit_code_trustable () {
 	true
 }

mergetools/kompare

@@ -2,10 +2,18 @@ can_merge () {
 	return 1
 }
 
+diff_cmd_help () {
+	echo "Use Kompare (requires a graphical session)"
+}
+
 diff_cmd () {
 	"$merge_tool_path" "$LOCAL" "$REMOTE"
 }
 
+merge_cmd_help () {
+	echo "Use Kompare (requires a graphical session)"
+}
+
 exit_code_trustable () {
 	true
 }

mergetools/meld

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" "$LOCAL" "$REMOTE"
 }
 
+diff_cmd_help () {
+	echo "Use Meld (requires a graphical session)"
+}
+
 merge_cmd () {
 	check_meld_for_features
 
@@ -20,6 +24,10 @@ merge_cmd () {
 	fi
 }
 
+merge_cmd_help () {
+	echo "Use Meld (requires a graphical session) with optional \`auto merge\` (see \`git help mergetool\`'s \`CONFIGURATION\` section)"
+}
+
 # Get meld help message
 init_meld_help_msg () {
 	if test -z "$meld_help_msg"

mergetools/opendiff

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" "$LOCAL" "$REMOTE" | cat
 }
 
+diff_cmd_help () {
+	echo "Use FileMerge (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -12,3 +16,7 @@ merge_cmd () {
 			-merge "$MERGED" | cat
 	fi
 }
+
+merge_cmd_help () {
+	echo "Use FileMerge (requires a graphical session)"
+}

mergetools/p4merge

@@ -19,6 +19,10 @@ diff_cmd () {
 	fi
 }
 
+diff_cmd_help () {
+	echo "Use HelixCore P4Merge (requires a graphical session)"
+}
+
 merge_cmd () {
 	if ! $base_present
 	then
@@ -34,3 +38,7 @@ create_empty_file () {
 
 	printf "%s" "$empty_file"
 }
+
+merge_cmd_help () {
+	echo "Use HelixCore P4Merge (requires a graphical session)"
+}

mergetools/smerge

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" mergetool "$LOCAL" "$REMOTE" -o "$MERGED"
 }
 
+diff_cmd_help () {
+	echo "Use Sublime Merge (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -10,3 +14,7 @@ merge_cmd () {
 		"$merge_tool_path" mergetool "$LOCAL" "$REMOTE" -o "$MERGED"
 	fi
 }
+
+merge_cmd_help () {
+	echo "Use Sublime Merge (requires a graphical session)"
+}

mergetools/tkdiff

@@ -2,6 +2,10 @@ diff_cmd () {
 	"$merge_tool_path" "$LOCAL" "$REMOTE"
 }
 
+diff_cmd_help () {
+	echo "Use TkDiff (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -14,3 +18,7 @@ merge_cmd () {
 exit_code_trustable () {
 	true
 }
+
+merge_cmd_help () {
+	echo "Use TkDiff (requires a graphical session)"
+}

mergetools/tortoisemerge

@@ -2,6 +2,10 @@ can_diff () {
 	return 1
 }
 
+diff_cmd_help () {
+	echo "Use TortoiseMerge (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -30,3 +34,7 @@ translate_merge_tool_path() {
 		echo tortoisemerge
 	fi
 }
+
+merge_cmd_help () {
+	echo "Use TortoiseMerge (requires a graphical session)"
+}

mergetools/winmerge

@@ -3,6 +3,10 @@ diff_cmd () {
 	return 0
 }
 
+diff_cmd_help () {
+	echo "Use WinMerge (requires a graphical session)"
+}
+
 merge_cmd () {
 	# mergetool.winmerge.trustExitCode is implicitly false.
 	# touch $BACKUP so that we can check_unchanged.
@@ -13,3 +17,7 @@ merge_cmd () {
 translate_merge_tool_path() {
 	mergetool_find_win32_cmd "WinMergeU.exe" "WinMerge"
 }
+
+merge_cmd_help () {
+	echo "Use WinMerge (requires a graphical session)"
+}

mergetools/xxdiff

@@ -12,6 +12,10 @@ diff_cmd () {
 	fi
 }
 
+diff_cmd_help () {
+	echo "Use xxdiff (requires a graphical session)"
+}
+
 merge_cmd () {
 	if $base_present
 	then
@@ -28,3 +32,7 @@ merge_cmd () {
 			--merged-file "$MERGED" "$LOCAL" "$REMOTE"
 	fi
 }
+
+merge_cmd_help () {
+	echo "Use xxdiff (requires a graphical session)"
+}