# Fix Suggest dropdown/inline completion partial accept (via next token/line) race

[marrej]

Repro steps:

monaco playground

Note that this is a race and does not trigger every time in the playground, but may be amplified by fullter event loop (running in vscode) offsetting the partialAccept trigger execution after the SuggestDropdown clear.

(Add breakpoints on the free & acceptPartial completion)

1. type e in the already existing consol
2. Once suggest dropdown console appears, accept next token/next line (e.g. ctrl+right)
3. Observe the order of events. The free completion for the id of the suggestion is called before the partialAccept

expected:
The partialAccept is called before free, otherwise the extHost reference to the item will get disposed prematurely.

The following snippet fixes it quickly by increasing the ref count to active completions (containing also standard inlineCompletions for consistency), and disposing after the partialAccept finished.

Note: If the onHide functionality is being implemented, the same may be required for the Accept as the reference to the active InlineCompletion might be dropped at the time the Hide event is triggered.

closes #195385

[hediet]

Thanks for this very deep investigation and the explanations!

What I don't understand at a first glance though, is why there is a race condition in the first place.
This code runs in sync, so I don't understand how timing can influence the behavior.

Actually, I don't think it is a race condition. Here is the stack from the repro:

freeInlineCompletions (VM264:158) - Deletes the inline completion
removeRef (provideInlineCompletions.ts:180)
dispose (provideInlineCompletions.ts:157)
dispose (inlineCompletionsSource.ts:231)
_setValue (base.ts:453)
set (base.ts:416)
clearSuggestWidgetInlineCompletions (inlineCompletionsSource.ts:116)
(anonymous) (inlineCompletionsModel.ts:123)
transaction (base.ts:228)
(anonymous) (inlineCompletionsModel.ts:118)
_recomputeIfNeeded (derived.ts:195)
get (derived.ts:172)
reportChanges (base.ts:153)
endUpdate (utils.ts:270)
endUpdate (derived.ts:252)
finish (base.ts:266)
transaction (base.ts:230)
update (suggestWidgetInlineCompletionProvider.ts:143)
(anonymous) (suggestWidgetInlineCompletionProvider.ts:105)
_deliver (event.ts:1121)
_deliverQueue (event.ts:1132)
fire (event.ts:1156)
hideWidget (suggestWidget.ts:748) - Suggest Widget hides
(anonymous) (suggestController.ts:272)
_deliver (event.ts:1121)
_deliverQueue (event.ts:1132)
fire (event.ts:1156)
cancel (suggestModel.ts:317)
_onNewContext (suggestModel.ts:738)
_refilterCompletionItems (suggestModel.ts:441)
(anonymous) (suggestModel.ts:202)
_deliver (event.ts:1121)
_deliverQueue (event.ts:1132)
fire (event.ts:1156)
(anonymous) (codeEditorWidget.ts:1656)
_deliver (event.ts:1121)
fire (event.ts:1152)
_emitOutgoingEvents (viewModelEventDispatcher.ts:64)
endEmitViewEvents (viewModelEventDispatcher.ts:109)
_withViewEventsCollector (viewModelImpl.ts:1092)
_executeCursorEdit (viewModelImpl.ts:1029)
executeEdits (viewModelImpl.ts:1032)
executeEdits (codeEditorWidget.ts:1215) - Edits are applied
(anonymous) (inlineCompletionsModel.ts:409)
(anonymous) (nls.ts:4)
__awaiter (nls.ts:4)
_acceptNext (inlineCompletionsModel.ts:376)
(anonymous) (inlineCompletionsModel.ts:338)
(anonymous) (nls.ts:4)
__awaiter (nls.ts:4)
acceptNextWord (inlineCompletionsModel.ts:337) - acceptNextWord
(anonymous) (commands.ts:102)
(anonymous) (nls.ts:4)
__awaiter (nls.ts:4)
run (commands.ts:100)
runEditorCommand (editorExtensions.ts:386)
(anonymous) (editorExtensions.ts:320)
(anonymous) (editorExtensions.ts:315)
invokeFunction (instantiationService.ts:68)
invokeWithinContext (codeEditorWidget.ts:434)
runEditorCommand (editorExtensions.ts:308)
runCommand (editorExtensions.ts:320)
handler (editorExtensions.ts:154)
invokeFunction (instantiationService.ts:68)
executeCommand (standaloneServices.ts:285)
_doDispatch (abstractKeybindingService.ts:327)
_dispatch (abstractKeybindingService.ts:184)
(anonymous) (standaloneServices.ts:327)