>> There is still a small problem:
>> sometimes it's handy to slightly edit a previous string
>> from kill-ring before inserting it.  But with completing-read
>> it's not easy to insert the space character, e.g. after 'M-p'
>> while editing, typing 'SPC' errors with "[No matches]"
>> and doesn't insert a space character.
>> 
>> Could you recommend a more lightweight version of 
>> completing-read that doesn't override the 'SPC' key?
>
> It's _always_ handy to be able to edit a kill-ring entry
> before inserting it into the minibuffer.

BTW, sometimes it's also handy to just browse the kill-ring
without immediately inserting an entry, to copy an edited entry
(that adds a new kill-ring entry) to paste later.  To allow
such browsing we need to remove "*" from the interactive spec of
'yank-pop'.

> It took decades to even get `SPC' to be self-inserting for
> `read-file-name'.  I raised the same issue for `completing-read' at
> that time (and before then).

So now a new patch let-binds (minibuffer-completing-file-name t)
around completing-read to allow inserting SPC, problem solved: