Fix: Prevent memory leak in view model lifecycle #40216
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michaeljolley
added
the
Product-Command Palette
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Pull Request Overview
This PR fixes a memory leak by disposing previous PageViewModel instances when CurrentPage is updated in ShellViewModel.
- Converted
CurrentPagefrom an auto-generated observable property to a manual property with disposal logic - Removed the
[ObservableProperty]attribute onCurrentPage - Added a backing field
_currentPageand custom setter to dispose old pages
Comments suppressed due to low confidence (2)
src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ShellViewModel.cs:34
- [nitpick] Add XML documentation to the
CurrentPageproperty to note that assigning a new page will dispose of the previous instance.
public PageViewModel CurrentPage
src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ShellViewModel.cs:42
- Consider adding a unit test to verify that when
CurrentPageis updated, the previousPageViewModelis properly disposed.
if (oldValue is IDisposable disposable)
src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ShellViewModel.cs
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Summary of the Pull Request
A memory leak was identified where activating a Command Palette extension via a hotkey would lead to a linear increase in resource consumption and a corresponding decrease in search performance.
Each activation created a new
PageViewModelinstance for the extension's UI. However, theShellViewModeldid not dispose of the previousPageViewModelinstance when a new one was created.The fix is implemented in
Microsoft.CmdPal.UI.ViewModels/ShellViewModel.csby ensuring thatPageViewModelinstances are correctly disposed of when they are no longer active.PR Checklist
Validation Steps Performed
GetItemsis invoked.Before the Fix (PowerToys v0.91.1)
GetItems12 times.2025-06-25.00-04-55.mp4
After the Fix
GetItemsonly once.after.fix.mp4