Fix suggest model triggering on disposed inline completions model

[ulugbekna]

Problem

The wait inside SuggestModel._waitForInlineCompletionsAndTrigger snapshotted inlineController.model.get() and then subscribed long-term to that snapshot's state / status derived observables.

Those derived observables are owned only for debug — they are not registered to the InlineCompletionsModel._store. The model itself is produced by a derivedDisposable in InlineCompletionsController and is disposed and recreated whenever its dependencies change:

• the editor's text model is replaced (peek opens, diff editor mode switch, programmatic editor.setModel(...), etc.)
• readOnly is toggled
• the controller is disposed (editor disposal)

After the model is disposed, its state / status derived keep observing live external dependencies (_editorObs.versionId, config observables, …) and continue to fire. SuggestModel does not call cancel() on onDidChangeConfiguration, so a readOnly toggle (concrete reproducer) leaves the wait running against a dead model:

• the unconditional 750 ms timeout calls inlineModel.stop('automatic') on a disposed instance (mutates _isActive on a dead model);
• the autorun fires triggerAndCleanUp(true) and can spuriously call this.trigger({ auto: true }).

Fix

Read inlineController.model as the first dependency of a single autorun. If the value differs from the snapshot we got at the start of the wait, the controller has swapped or disposed the model — bail out before any read on state / status.

A single autorun (rather than a nested outer/inner pair) is deliberate: independent autoruns share no run-ordering guarantee, so an inner state watcher could otherwise run on a disposed model before the outer model watcher cleaned it up.

Test

Added a regression test that:

1. registers a hanging inline completions provider that only resolves on cancellation,
2. types a character so the wait is set up,
3. toggles readOnly: true mid-wait (disposes the model),
4. advances past the 750 ms timeout and asserts that quick suggest is not fired.

Verified the test fails on the original code and passes on the fix.

[Copilot]

Pull request overview

Fixes a race in SuggestModel._waitForInlineCompletionsAndTrigger where the wait could keep observing InlineCompletionsModel-owned derived observables after the inline model had been disposed/recreated (e.g. due to readOnly toggling), potentially leading to stop()/auto-trigger being applied to a dead inline model.

Changes:

• Bind the inline-completions wait to the current inline model by reading inlineController.model first within a single autorun, and bailing out when the model instance changes.
• Add a regression test that disposes the inline model mid-wait by toggling readOnly, then verifies quick suggest is not triggered after the 750ms timeout window.

Show a summary per file

File	Description
src/vs/editor/contrib/suggest/browser/suggestModel.ts	Ensures the inline-completions wait observes the controller’s current model instance and cleans up when it changes, avoiding actions on disposed models.
src/vs/editor/contrib/suggest/test/browser/suggestModel.test.ts	Adds coverage for the mid-wait inline model disposal scenario (via readOnly toggle) to prevent regressions.

Copilot's findings

• Files reviewed: 2/2 changed files
• Comments generated: 0