wgrep.el does not work on Emacs 26

[Lele Gaifax <lele@metapensiero.it>]

Hi,

since some time now wgrep[*] does not work anymore in my Emacs 26
installation. 

I cannot be 100% sure, but I seem to remember it used to work with that
version (I recompile my Emacs every month or so, refreshing its sources from
the repository).

Today I tried to dig into the issue, but with no luck. I then compiled an
Emacs 25 just to test it, and no surprise, there it works as expected.

On Emacs 26, its standard keybinding C-c C-p (wgrep-change-to-wgrep-mode) does
not alter the buffer readonly state, but even when toggling it manually with
C-x C-q the *grep* buffer remains unmodifiable; when I tried setting
inhibit-read-only to t, I was able to change its content, but applying the
changes with C-c C-e (wgrep-finish-edit) emits only the message "(No changes
to be performed)"...

I noticed that the normal wgrep behaviour of using a "green" face for the
modifications (that is, when in wgrep-mode, altering the matched lines makes
them appear with a green background...) does not happen neither.

Any hint on where to dig deeper, or on alternative to wgrep?

Thanks in advance,
ciao, lele.

[*] https://github.com/mhayashi1120/Emacs-wgrep
-- 
nickname: Lele Gaifax | Quando vivrò di quello che ho pensato ieri
real: Emanuele Gaifas | comincerò ad aver paura di chi mi copia.
lele@metapensiero.it  |                 -- Fortunato Depero, 1929.