bug#65348: INITIAL-INPUT in completing-read repeats same entry twice consecutively

[Eli Zaretskii]

> Date: Thu, 17 Aug 2023 06:05:06 +0000
> From: Heime <heimeborgia@protonmail.com>
> Cc: 65348@debbugs.gnu.org
> 
> > Sorry, I don't understand what you are saying. What do you mean by
> > "is displayed twice consecutively"? I guess some details are missing
> > from your report to make it complete and self-explanatory?
> 
> Consider the function defined by
> 
> (defun bigops (grafm seltr)
>   (interactive
>     (let ( (collecj '("boxplus" "boxtimes" "Cap" "centerdot" "circledast")) )
>       (completing-read "Grapheme: " collecj nil t "boxplus")))
> 
> The user would see "boxplus", then the following element shows "boxplus"
> consecutively again.  Could you consider the capability that when one uses
> REQUIRE-MATCH, the function finds the entry for INITIAL-INPUT so that the 
> next thing that gets shown after that starts from the one following the 
> match in COLLECTION.  Otherwise, one is forced to put the INITIAL-INPUT
> entry at the end of COLLECTION.

Sorry, I still don't understand: what are "the following element" and
"the next thing that gets shown"?  Shown how?  What causes them to be
shown?