bash 4.4 - (readline) regression in the behaviour of ^W in vi-mode

[Gian Piero Carrubba]

* Please cc me as I'm not subscribed.

Hello all,

this is a copy of Debian bug 838437 [0]. I'm posting it here because I 
failed to find it mentioned in the ml archives. Please disregard if it's 
been already reported.

---

$ set -o vi
$ echo REMOVE maintain

With bash-4.3-15 I can recall and modify the line positioning the cursor
on the space between 'REMOVE' and 'maintain' and using ^W:

Esc, k, e, e, l, i, Ctrl-w 

With bash-4.4-1 this doesn't work (does nothing), and I have to position
the cursor on the start of the next word:

Esc, k, w, w, i, Ctrl-w, Ctrl-w

Anyway, it DOES work if I try to remove only part of the word (e.g.:
leaving the last E):

Esc, k, e, e, i, Ctrl-w

Where it really becomes nasty is in presence of non alphanum chars:

$ echo REMOVE .maintain

Positioning the cursor on the dot succeeds in removing the space but
then stop working:

Esc, k, w, w, i, Ctrl-w, Ctrl-w

OTOH, positioning the cursor on the char following the dot works (but in
this case removes space and dot together as if there are no word
boundaries):

Esc, k, w, w, w, i, Ctrl-w, Ctrl-w

Trying to modify a line like

$ ls /tmp/ /var/

with ^W can be frustrating depending on where you start from.

As from my limited tests, this issue does not seem affected by locale
settings.

I've verified this bug still exists as of patch 11. Patch 12 does not 
seem related (but I can be wrong).

Best,
Gian Piero.

[0] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=838437