refactor(completer)!: don't require Send on the Completer trait#1092
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kronberger-droid wants to merge 1 commit into
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refactor(completer)!: don't require Send on the Completer trait#1092kronberger-droid wants to merge 1 commit into
kronberger-droid wants to merge 1 commit into
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The `unsafe impl Send` on `HistoryCompleter` was sound (a pub(crate) stack-local, never sent across threads) but it revealed that `Completer: Send` is too tight: not every completer needs to be Send. Drop `Send` from the `Completer` trait and require it only on the owned completers stored in `Reedline` and `ReedlineMenu::WithCompleter`, now `Box<dyn Completer + Send>`. The `unsafe` falls away with no new bound on `History`, so `SqliteBackedHistory` (`!Sync` connection) stays untouched. Alternative to nushell#929, which fixed the same `unsafe` via `History: Sync` but broke the sqlite backend. Adds `reedline_is_send` as a compile-time guard. BREAKING CHANGE: `Completer` no longer requires `Send`. `with_completer` and `ReedlineMenu::WithCompleter` now take `Box<dyn Completer + Send>`. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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The
unsafe impl SendonHistoryCompleterwas actually sound: it's apub(crate)type only ever created as a stack local and borrowed into menus, never sent across threads.But it pointed at a trait that's too tight, since
Completer: Sendforces every completer to beSend.So instead of asserting
Sendwhere it isn't required, this drops it from theCompletertrait and requires it only on the completers that are actually owned and stored, thus inReedlineandReedlineMenu::WithCompleter, nowBox<dyn Completer + Send>.The
unsafefalls away naturally, with no new bound onHistory, soSqliteBackedHistory(whoserusqlite::Connectionis!Sync) is untouched.This is an alternative to #929, which tightened
History: Syncto fix the sameunsafebut broke the sqlite backend as a result.Added
reedline_is_sendas a compile-time guard on the relocated bound.API note:
with_completerandReedlineMenu::WithCompleternow takeBox<dyn Completer + Send>. Source-compatible (the oldCompleter: Sendalready required it), but visible in signatures.