Miscellaneous minor updates to WinCompat (#11980)

* Filter PSModulePath when starting PS 5.1. Removing PS-Core-specific paths from PSModulePath of WinCompat process (Windows PS).
* Make implicit WinCompat respect NoClobber and Scope parameters
* Add ErrorAction.Ignore when searching for WinPSCompatSession

src/System.Management.Automation/engine/Modules/ModuleCmdletBase.cs

@@ -2359,7 +2359,7 @@ namespace Microsoft.PowerShell.Commands
                 {
                     if (importingModule)
                     {
-                        IList<PSModuleInfo> moduleProxies = ImportModulesUsingWinCompat(new string[] { moduleManifestPath }, null, new ImportModuleOptions());
+                        IList<PSModuleInfo> moduleProxies = ImportModulesUsingWinCompat(new string[] { moduleManifestPath }, null, options);
 
                         // we are loading by a single ManifestPath so expect max of 1
                         if (moduleProxies.Count > 0)
@@ -4799,6 +4799,7 @@ namespace Microsoft.PowerShell.Commands
             using var ps = System.Management.Automation.PowerShell.Create(RunspaceMode.CurrentRunspace);
             ps.AddCommand(commandInfo);
             ps.AddParameter("Name", WindowsPowerShellCompatRemotingSessionName);
+            ps.AddParameter("ErrorAction", ActionPreference.Ignore);
             var results = ps.Invoke<PSSession>();
             if (results.Count > 0)
             {

src/System.Management.Automation/engine/hostifaces/PowerShellProcessInstance.cs

@@ -93,13 +93,16 @@ namespace System.Management.Automation.Runspaces
                 LoadUserProfile = true,
 #endif
             };
-
+#if !UNIX
             if (startingWindowsPowerShell51)
             {
                 _startInfo.ArgumentList.Add("-Version");
                 _startInfo.ArgumentList.Add("5.1");
-            }
 
+                // if starting Windows PowerShell, need to remove PowerShell specific segments of PSModulePath
+                _startInfo.Environment["PSModulePath"] = ModuleIntrinsics.GetWindowsPowerShellModulePath();
+            }
+#endif
             _startInfo.ArgumentList.Add("-s");
             _startInfo.ArgumentList.Add("-NoLogo");
             _startInfo.ArgumentList.Add("-NoProfile");

test/powershell/Modules/Microsoft.PowerShell.Core/CompatiblePSEditions.Module.Tests.ps1

@@ -355,6 +355,20 @@ Describe "Import-Module from CompatiblePSEditions-checked paths" -Tag "CI" {
                 Set-Location $pwdBackup
             }
         }
+
+        It "-NoClobber and -Scope work with implicit WinCompat" -TestCases $failCases -Skip:(-not $IsWindows) {
+            param($Editions, $ModuleName, $Result)
+            try
+            {
+                Set-Item function:Test-$ModuleName {"OriginalFunctionImplementation"}
+                Import-Module $ModuleName -Force -WarningAction Ignore -Scope Local -NoClobber
+                & "Test-$ModuleName" | Should -BeExactly "OriginalFunctionImplementation"
+            }
+            finally
+            {
+                Remove-Item function:Test-$ModuleName
+            }
+        }
     }
 
     Context "Imports from absolute path" {
@@ -429,6 +443,7 @@ Describe "Additional tests for Import-Module with WinCompat" -Tag "Feature" {
         $ModuleName = "DesktopModule"
         $ModuleName2 = "DesktopModule2"
         $basePath = Join-Path $TestDrive "WinCompatModules"
+        $allModules = @($ModuleName, $ModuleName2)
         Remove-Item -Path $basePath -Recurse -ErrorAction SilentlyContinue
         # create an incompatible module that generates an error on import
         New-EditionCompatibleModule -ModuleName $ModuleName -CompatiblePSEditions "Desktop" -Dir $basePath -ErrorGenerationCode '1/0;'
@@ -538,6 +553,62 @@ Describe "Additional tests for Import-Module with WinCompat" -Tag "Feature" {
             $out | Should -BeExactly 'CouldNotAutoloadMatchingModule'
         }
     }
+
+    Context "Tests around PSModulePath in WinCompat process" {
+        BeforeAll {
+            $pwsh = "$PSHOME/pwsh"
+            Add-ModulePath $basePath
+            $ConfigPath = Join-Path $TestDrive 'powershell.config.json'
+        }
+
+        AfterAll {
+            Restore-ModulePath
+        }
+
+        AfterEach {
+            Get-Module $allModules | Remove-Module -Force
+        }
+
+        It 'WinCompat process does not inherit PowerShell-Core-specific paths' {
+            # these paths were copied from test\powershell\engine\Module\ModulePath.Tests.ps1
+            $pscoreUserPath = Join-Path -Path $HOME -ChildPath "Documents\PowerShell\Modules"
+            $pscoreSharedPath = Join-Path -Path $env:ProgramFiles -ChildPath "PowerShell\Modules"
+            $pscoreSystemPath = Join-Path -Path $PSHOME -ChildPath 'Modules'
+
+            $pscorePaths = $env:psmodulepath
+            $pscorePaths | Should -BeLike "*$pscoreUserPath*"
+            $pscorePaths | Should -BeLike "*$pscoreSharedPath*"
+            $pscorePaths | Should -BeLike "*$pscoreSystemPath*"
+
+            Import-Module $ModuleName2 -UseWindowsPowerShell -Force -WarningAction Ignore
+            $s = Get-PSSession -Name WinPSCompatSession
+            $winpsPaths = Invoke-Command -Session $s -ScriptBlock {$env:psmodulepath}
+            $winpsPaths | Should -Not -BeLike "*$pscoreUserPath*"
+            $winpsPaths | Should -Not -BeLike "*$pscoreSharedPath*"
+            $winpsPaths | Should -Not -BeLike "*$pscoreSystemPath*"
+        }
+
+        It 'WinCompat process inherits user added paths' {
+            $mypath = Join-Path $env:SystemDrive MyDir
+            $originalModulePath = $env:PSModulePath
+            try {
+                $env:PSModulePath += ";$mypath"
+                Import-Module $ModuleName2 -UseWindowsPowerShell -Force -WarningAction Ignore
+                $s = Get-PSSession -Name WinPSCompatSession
+                $winpsPaths = Invoke-Command -Session $s -ScriptBlock {$env:psmodulepath}
+                $winpsPaths | Should -BeLike "*$mypath*"
+            }
+            finally {
+                $env:PSModulePath = $originalModulePath
+            }
+        }
+
+        It 'Windows PowerShell does not inherit path defined in powershell.config.json' {
+            '{ "PSModulePath": "C:\\MyTestDir" }' | Out-File -Force $ConfigPath
+            $winpsPaths =  & $pwsh -NoProfile -NonInteractive -settingsFile $ConfigPath -c "Import-Module $ModuleName2 -UseWindowsPowerShell -WarningAction Ignore;`$s = Get-PSSession -Name WinPSCompatSession;Invoke-Command -Session `$s -ScriptBlock {`$env:psmodulepath}"
+            $winpsPaths | Should -Not -BeLike "*MyTestDir*"
+        }
+    }
 }
 
 Describe "PSModulePath changes interacting with other PowerShell processes" -Tag "Feature" {

test/powershell/engine/Module/ModulePath.Tests.ps1

@@ -165,9 +165,9 @@ Describe "SxS Module Path Basic Tests" -tags "CI" {
 
     It 'Windows PowerShell does not inherit PowerShell paths' -Skip:(!$IsWindows) {
         $out = powershell.exe -noprofile -command '$env:PSModulePath'
-        $out | Should -Not -Contain $expectedUserPath
-        $out | Should -Not -Contain $expectedSharedPath
-        $out | Should -Not -Contain $expectedSystemPath
+        $out | Should -Not -BeLike "*$expectedUserPath*"
+        $out | Should -Not -BeLike "*$expectedSharedPath*"
+        $out | Should -Not -BeLike "*$expectedSystemPath*"
     }
 
     It 'Windows PowerShell inherits user added paths' -Skip:(!$IsWindows) {