Re: [BUG] Regression in 'git mergetool --tool-help'

Thanks for both answers. Felipe's solution does the trick, but Junio's
does not;
it seems we do have to have a newline there. The following also works,
and I think
is portable:

diff --git i/git-mergetool--lib.sh w/git-mergetool--lib.sh
index 2defef28cd..6f03975493 100644
--- i/git-mergetool--lib.sh
+++ w/git-mergetool--lib.sh

@@ -46,7 +46,7 @@ show_tool_names () {

         while read scriptname
         do
             setup_tool "$scriptname" 2>/dev/null
-            variants="$variants$(list_tool_variants)\n"
+            variants="$(echo "$variants" && list_tool_variants)"
         done
         variants="$(echo "$variants" | sort | uniq)"

I figured out what was different between the different Ubuntu versions I
was testing:
the Ubuntu 14 and 18 systems have Bash as /bin/sh, but my Ubuntu 20 system
has /usr/bin/dash as /bin/sh (the default for Ubuntu these days).

I'll try to send a formal patch with the diff above, time permitting...