Allow pwsh to inherit $env:PSModulePath and enable powershell.exe to start correctly (#11057)

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

@@ -3,7 +3,6 @@
 Describe "SxS Module Path Basic Tests" -tags "CI" {
 
     BeforeAll {
-
         if ($IsWindows)
         {
             $powershell = "$PSHOME\pwsh.exe"
@@ -14,13 +13,22 @@ Describe "SxS Module Path Basic Tests" -tags "CI" {
             }
             $expectedUserPath = Join-Path -Path $HOME -ChildPath "Documents\$ProductName\Modules"
             $expectedSharedPath = Join-Path -Path $env:ProgramFiles -ChildPath "$ProductName\Modules"
+            $userConfigPath = "~/Documents/powershell/powershell.config.json"
         }
         else
         {
             $powershell = "$PSHOME/pwsh"
             $expectedUserPath = [System.Management.Automation.Platform]::SelectProductNameForDirectory("USER_MODULES")
             $expectedSharedPath = [System.Management.Automation.Platform]::SelectProductNameForDirectory("SHARED_MODULES")
+            $userConfigPath = "~/.config/powershell/powershell.config.json"
         }
+
+        $userConfigExists = $false
+        if (Test-Path $userConfigPath) {
+            $userConfigExists = $true
+            Copy-Item $userConfigPath "$userConfigPath.backup" -Force -ErrorAction Ignore
+        }
+
         $expectedSystemPath = Join-Path -Path $PSHOME -ChildPath 'Modules'
 
         # Skip these tests in cases when there is no 'pwsh' executable (e.g. when framework dependent PS package is used)
@@ -41,6 +49,15 @@ Describe "SxS Module Path Basic Tests" -tags "CI" {
         New-Item -Path $fakePSHomeModuleDir -ItemType Directory > $null
     }
 
+    AfterAll {
+        if ($userConfigExists) {
+            Move-Item "$userConfigPath.backup" $userConfigPath -Force -ErrorAction Ignore
+        }
+        else {
+            Remove-Item "$userConfigPath" -Force -ErrorAction Ignore
+        }
+    }
+
     BeforeEach {
         $originalModulePath = $env:PSModulePath
     }
@@ -74,7 +91,7 @@ Describe "SxS Module Path Basic Tests" -tags "CI" {
         }
     }
 
-    It "ignore pshome module path derived from a different PowerShell instance" -Skip:(!$IsCoreCLR -or $skipNoPwsh) {
+    It "Works with pshome module path derived from a different PowerShell instance" -Skip:(!$IsCoreCLR -or $skipNoPwsh) {
 
         ## Create 'powershell' and 'pwsh.deps.json' in the fake PSHome folder,
         ## so that the module path calculation logic would believe it's real.
@@ -88,21 +105,15 @@ Describe "SxS Module Path Basic Tests" -tags "CI" {
             $newModulePath = & $powershell -nopro -c '$env:PSModulePath'
             $paths = $newModulePath -split [System.IO.Path]::PathSeparator
 
-            if ($IsWindows)
-            {
-                $paths.Count | Should -Be 4
-            }
-            else
-            {
-                $paths.Count | Should -Be 3
-            }
+            $paths.Count | Should -Be 4
 
             $paths[0] | Should -Be $expectedUserPath
             $paths[1] | Should -Be $expectedSharedPath
             $paths[2] | Should -Be $expectedSystemPath
+            $paths[3] | Should -Be $fakePSHomeModuleDir
             if ($IsWindows)
             {
-                $paths[3].TrimEnd([System.IO.Path]::DirectorySeparatorChar) | Should -Be $expectedWindowsPowerShellPSHomePath
+                $expectedWindowsPowerShellPSHomePath | Should -Not -BeIn $paths
             }
 
         } finally {
@@ -120,15 +131,7 @@ Describe "SxS Module Path Basic Tests" -tags "CI" {
         $env:PSModulePath = $fakePSHomeModuleDir, $customeModules -join ([System.IO.Path]::PathSeparator)
         $newModulePath = & $powershell -nopro -c '$env:PSModulePath'
         $paths = $newModulePath -split [System.IO.Path]::PathSeparator
-
-        if ($IsWindows)
-        {
-            $paths.Count | Should -Be 6
-        }
-        else
-        {
-            $paths.Count | Should -Be 5
-        }
+        $paths.Count | Should -Be 5
         $paths -contains $fakePSHomeModuleDir | Should -BeTrue
         $paths -contains $customeModules | Should -BeTrue
     }
@@ -162,4 +165,24 @@ Describe "SxS Module Path Basic Tests" -tags "CI" {
         $wpshIndex | Should -Not -Be -1
         $pwshIndex | Should -BeLessThan $wpshIndex
     }
+
+    It 'Windows PowerShell does not inherit PowerShell paths' -Skip:(!$IsWindows) {
+        $out = powershell.exe -noprofile -command '$env:PSModulePath'
+        $out | Should -Not -Contain $expectedUserPath
+        $out | Should -Not -Contain $expectedSharedPath
+        $out | Should -Not -Contain $expectedSystemPath
+    }
+
+    It 'Windows PowerShell inherits user added paths' -Skip:(!$IsWindows) {
+        $env:PSModulePath += ";myPath"
+        $out = powershell.exe -noprofile -command '$env:PSModulePath'
+        $out | Should -BeLike '*;myPath'
+    }
+
+    It 'Windows PowerShell does not inherit path defined in powershell.config.json' -Skip:(!$IsWindows) {
+        $userConfig = '{ "PSModulePath": "myUserPath" }'
+        Set-Content -Path $userConfigPath -Value $userConfig -Force
+        $out = pwsh -noprofile -command 'powershell.exe -noprofile -command $env:PSModulePath'
+        $out | Should -Not -BeLike 'myUserPath;*'
+    }
 }