Maintenance: OutputPanelScopeImpl - Fix stale outputPanel reference

[claude]

Summary

• Area inspected: vim-engine/src/main/kotlin/com/maddyhome/idea/vim/thinapi/OutputPanelScopeImpl.kt
• Starting point was a random file (VimOutputPanelServiceBase.kt), which led to inspecting the related OutputPanelScopeImpl

Issue Found

When OutputPanelScopeImpl was changed from a class to an object singleton (commit 04d9282fb), the outputPanel property was left as a backing field:

private val outputPanel: VimOutputPanel = injector.outputPanel.getOrCreate(vimEditor, vimContext)

Since this is a Kotlin object, this field is initialized once when the singleton is first accessed. All subsequent calls to setText, appendText, clearText, etc. reuse the same stale VimOutputPanel instance — even if:

• The user switched to a different editor
• The original panel was closed (via user pressing q, or listeners in VimListenerManager/MotionGroup calling close())

Before the class→object change, OutputPanelScopeImpl() was instantiated fresh for each api.outputPanel { ... } call, so getOrCreate was called each time. After the change, that fresh evaluation only happens once.

Change Made

Made outputPanel a computed property with an explicit get(), consistent with:

• vimEditor and vimContext in the same class
• optionGroup in OptionScopeImpl

private val outputPanel: VimOutputPanel
    get() = injector.outputPanel.getOrCreate(vimEditor, vimContext)

This ensures each method call gets the current active panel (or creates a new one for the currently focused editor) via the existing getOrCreate mechanism.

Why This Improves the Code

• Eliminates potential stale reference bugs when the output panel is closed and re-opened
• Ensures the correct panel is used when the user switches editors between plugin calls
• Makes the property consistent with the other computed properties in the same object