performance.debounce breaks cmdline completion

[JeanMertz]

FAQ

• I have checked the FAQ and it didn't resolve my problem.

Announcement

• I have checked Breaking change announcement.

Minimal reproducible full config

Description

After I added performance.debounce = 500 to my global cmp config, I noticed that my cmp cmdline completion was broken. Specifically, triggering the completion was still instant, but now, after the debounce timer, it would "reevaluate" whatever completion was currently shown in the command-line, and use that as the new input for the completion list.

To be specific, here's what would happen:

As an example:

:e

the list of completions returned (truncated):

earlier
echo
echoerr
echohl
edit

I tap and hold <Tab> and it cycles through those 5 items one by one. Then, often but not always (presumably depending on what the state of the completion is when the debounce triggers), it "locks" into one of those items, so that now the new input is:

:echohl

And the new list of possible options changes:

echohl
echo "hello"
echo hello
echo vim.v.hlsearch

(those last three are from the cmdline-history plugin)

Steps to reproduce

Expected behavior

Actual behavior

Additional context

Setting debounce to 0 either in the global setup or in setup.cmdline resolves the issue.

[Shougo]

Hm... The debounce seems update candidates later.
So it is faster but it is not exactly.