Re: Teach completion to insert a common prefix

[sbaugh@catern.com]

Pierre Rouleau <prouleau001@gmail.com> writes:

>> All possible completions for -matching-lines- start with
>> > list-matching-lines-.  So there would be no harm in inserting "list" at
>> > the start of the completion input.  But Emacs does not do this.
>>
>> It does do that if you put the point at the start of line.
>>
>> Note that older versions of Emacs was also doing that even when point was
> at the end of the line, as in Emacs 26.3
>
> Do you know when that changed and why?

I think this is just a bug, maybe introduced in Emacs 26.  I fixed it in
bug#65137: 29.1; completion-substring-try-completion doesn't return the
longest common substring.