From: JuanJo Ciarlante <jjo@canonical.com>
Subject: fix _quote_readline_by_ref to:
 - avoid escaping 1st '~' (lp: #1288314)
 - avoid quoting if empty, else expansion without args only shows dirs
   (lp: #1288031)
 - replace double escaping to single (eg for completing file/paths with
   spaces)
Origin: vendor, https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=739835
Bug-Debian: https://bugs.debian.org/739835
Forwarded: yes, <5328F418.100@canonical.com>

---
 bash_completion |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

--- a/bash_completion
+++ b/bash_completion	2023-08-17 12:16:26.654187550 +0000
@@ -542,13 +542,24 @@ __ltrim_colon_completions()
 # @param $2  Name of variable to return result to
 _quote_readline_by_ref()
 {
-    if [[ $1 == \'* ]]; then
+    if [ -z "$1" ]; then
+        # avoid quoting if empty
+        printf -v $2 %s "$1"
+    elif [[ $1 == \'* ]]; then
         # Leave out first character
         printf -v $2 %s "${1:1}"
+    elif [[ $1 == ~* ]]; then
+        # avoid escaping first ~
+        printf -v $2 ~%q "${1:1}"
     else
         printf -v $2 %q "$1"
     fi
 
+    # Replace double escaping ( \\ ) by single ( \ )
+    # This happens always when argument is already escaped at cmdline,
+    # and passed to this function as e.g.: file\ with\ spaces
+    [[ ${!2} == *\\* ]] && printf -v $2 %s "${1//\\\\/\\}"
+
     # If result becomes quoted like this: $'string', re-evaluate in order to
     # drop the additional quoting.  See also:
     # https://www.mail-archive.com/bash-completion-devel@lists.alioth.debian.org/msg01942.html