`background-completions` experimental option

[kronberger-droid]

Identifier

background-completions

Introducing PR

#18764

Status

opt-out

Description

background-completions (added in #18764) runs REPL completions on a worker thread so typing never blocks.
The async path is the default under test, and disabling it restores the pre-#18334 blocking behavior so custom completers can drive interactive child processes ($candidates | fzf, see #18771).

This issue tracks how the option ends its life. Either:

• the async path stabilizes as the only behavior once interactive completers have a supported path of their own, and the option is removed, or
• problems surface that keep the blocking path necessary, and the option graduates to a proper config setting.

Related

#18764
#18334
#18771