Add 'Restart Windows Explorer' command, implemented using Restart Manager

[jiripolasek]

Summary of the Pull Request

• Adds a new "Restart Windows Explorer" command to the "Windows System Commands" provider
• Implemented using Restart Manager to allow restoring previously opened Explorer windows after restart
  • This depends on the "Restore previous folder windows at logon" option in File Explorer Options
  • An explicit timeout was added for terminating processes, since Restart Manager uses very long timeouts 😴
• The shell process name (explorer) is hardcoded
• The command attempts to terminate all explorer processes indiscriminately
• Execution requires confirmation (if enabled in settings)

PR Checklist

• Closes: [CmdPal] Restart Explorer option in Windows System Command #39213
• Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
• Tests: Added/updated and all pass
• Localization: All end user facing strings can be localized
• Dev docs: Added/updated
• New binaries: Added on the required places
  • JSON for signing for new binaries
  • WXS for installer for new binaries and localization folder
  • YML for CI pipeline for new test projects
  • YML for signed pipeline
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

[jiripolasek]

@microsoft-github-policy-service agree

[Copilot]

Pull Request Overview

Adds a new “Restart Windows Explorer” command to the Windows System Commands provider, leveraging the Restart Manager API to gracefully terminate and relaunch explorer.exe.

• Introduces localization entries for command name, description, confirmation
• Implements ShellRestartHelper to orchestrate process shutdown/restart via Restart Manager
• Updates command registry, icons, and native interop definitions

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.System/Properties/Resources.resx	Added resource strings for the new restart command
src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.System/Helpers/ShellRestartHelper.cs	New helper class to restart explorer.exe using Restart Manager
src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.System/Helpers/NativeMethods.cs	Added P/Invoke signatures and structs for Restart Manager APIs
src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.System/Helpers/Icons.cs	Added an icon entry for the shell restart command
src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.System/Helpers/Commands.cs	Registered the Restart Windows Explorer command
.github/actions/spell-check/expect.txt	Whitelisted “rstrtmgr” for spell-checker

Files not reviewed (1)

• src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.System/Properties/Resources.Designer.cs: Language not supported

Comments suppressed due to low confidence (2)

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.System/Helpers/ShellRestartHelper.cs:26

• There are no unit tests covering ShellRestartHelper. Adding tests for the restart logic (e.g., mocking NativeMethods) would improve confidence in this complex behavior.

internal static async Task RestartAllInCurrentSession()

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.System/Properties/Resources.resx:427

• [nitpick] The command name value is too generic. Consider using a more descriptive label like "Restart Explorer" to match the title and avoid UI ambiguity.

<value>Restart</value>

[Copilot]

Unnecessary use of Task.Run inside the command callback may complicate error propagation and cancellation. Consider passing the async method directly (e.g. static () => ShellRestartHelper.RestartAllInCurrentSession()).

Suggested change

	results.Add(new ListItem(new ExecuteCommandConfirmation(Resources.Microsoft_plugin_sys_RestartShell_name!, confirmCommands, Resources.Microsoft_plugin_sys_RestartShell_confirmation!, static () => Task.Run(static () => ShellRestartHelper.RestartAllInCurrentSession())))
	results.Add(new ListItem(new ExecuteCommandConfirmation(Resources.Microsoft_plugin_sys_RestartShell_name!, confirmCommands, Resources.Microsoft_plugin_sys_RestartShell_confirmation!, static () => ShellRestartHelper.RestartAllInCurrentSession()))

[Copilot]

The executable name "explorer.exe" is hard-coded in multiple places. Extract it to a private constant to avoid duplication and potential typos.

Suggested change

	await RestartProcessesInCurrentSessionAsync("explorer.exe");
	// - Windows can automatically restart the shell if it detects that it has crashed. This can be disabled
	// in registry (key AutoRestartShell).
	// - Restart Manager is not guaranteed to restart all the processes it closes.
	await EnsureProcessIsRunning("explorer.exe");
	await RestartProcessesInCurrentSessionAsync(ExplorerExecutableName);
	// - Windows can automatically restart the shell if it detects that it has crashed. This can be disabled
	// in registry (key AutoRestartShell).
	// - Restart Manager is not guaranteed to restart all the processes it closes.
	await EnsureProcessIsRunning(ExplorerExecutableName);

[Copilot]

[nitpick] The P/Invoke signatures use IntPtr but the code uses nint for session handles. For consistency and clarity, consider using IntPtr throughout.

Suggested change

	var restartManagerSessionHandle = nint.Zero;
	var restartManagerSessionHandle = IntPtr.Zero;