Allow commands to still be executed even if the current working directory no longer exists (PowerShell#17579)

Author: SteveL-MSFT

src/Microsoft.PowerShell.Commands.Management/commands/management/Process.cs

@@ -1908,8 +1908,12 @@ protected override void BeginProcessing()
             }
             else
             {
-                // Working Directory not specified -> Assign Current Path.
-                startInfo.WorkingDirectory = PathUtils.ResolveFilePath(this.SessionState.Path.CurrentFileSystemLocation.Path, this, isLiteralPath: true);
+                // Working Directory not specified -> Assign Current Path, but only if it still exists
+                var currentDirectory = PathUtils.ResolveFilePath(this.SessionState.Path.CurrentFileSystemLocation.Path, this, isLiteralPath: true);
+                if (Directory.Exists(currentDirectory))
+                {
+                    startInfo.WorkingDirectory = currentDirectory;
+                }
             }
 
             if (this.ParameterSetName.Equals("Default"))

src/System.Management.Automation/engine/CommandPathSearch.cs

@@ -110,7 +110,17 @@ private void ResolveCurrentDirectoryInLookupPaths()
                 sessionState.CurrentDrive.Provider.NameEquals(fileSystemProviderName) &&
                 sessionState.IsProviderLoaded(fileSystemProviderName);
 
-            string environmentCurrentDirectory = Directory.GetCurrentDirectory();
+            string? environmentCurrentDirectory = null;
+            
+            try
+            {
+                environmentCurrentDirectory = Directory.GetCurrentDirectory();
+            }
+            catch (FileNotFoundException)
+            {
+                // This can happen if the current working directory is deleted by another process on non-Windows
+                // In this case, we'll just ignore it and continue on with the current directory as null
+            }
 
             LocationGlobber pathResolver = _context.LocationGlobber;
 

src/System.Management.Automation/engine/NativeCommandProcessor.cs

@@ -1378,7 +1378,12 @@ private ProcessStartInfo GetProcessStartInfo(
             string rawPath =
                 context.EngineSessionState.GetNamespaceCurrentLocation(
                     context.ProviderNames.FileSystem).ProviderPath;
-            startInfo.WorkingDirectory = WildcardPattern.Unescape(rawPath);
+
+            // Only set this if the PowerShell's current working directory still exists.
+            if (Directory.Exists(rawPath))
+            {
+                startInfo.WorkingDirectory = WildcardPattern.Unescape(rawPath);
+            }
 
             return startInfo;
         }

test/powershell/Language/Scripting/NativeExecution/NativeCommandProcessor.Tests.ps1

@@ -51,6 +51,54 @@ Describe 'native commands with pipeline' -tags 'Feature' {
         Start-Sleep -Milliseconds 500
         (Get-Process 'yes' -ErrorAction Ignore).Count | Should -Be $yes
     }
+
+    It 'native command should still execute if the current working directory no longer exists with command: <command>' -Skip:($IsWindows) -TestCases @(
+        @{ command = 'ps' }
+        @{ command = 'start-process ps -nonewwindow'}
+    ){
+        param($command)
+
+        $wd = New-Item testdrive:/tmp -ItemType directory
+        $lock = New-Item testdrive:/lock -ItemType file
+        $script = @"
+            while (`$null -ne (Get-Item "$lock" -ErrorAction Ignore)) {
+                Start-Sleep -Seconds 1
+            }
+
+            try {
+                `$out = $command
+            }
+            catch {
+                `$null = Set-Content -Path "$testdrive/error" -Value (`$_ | Out-String)
+            }
+
+            `$null = Set-Content -Path "$testdrive/out" -Value `$out
+"@
+
+        $pwsh = Start-Process -FilePath "${PSHOME}/pwsh" -WorkingDirectory $wd -ArgumentList @('-noprofile','-command',$script)
+
+        Remove-Item -Path $wd -Force
+        Remove-Item $lock
+        $start = Get-Date
+
+        try {
+            while ($null -eq (Get-Item "$testdrive/error" -ErrorAction Ignore) -and $null -eq (Get-Item "$testdrive/out" -ErrorAction Ignore)) {
+                if (((Get-Date) - $start).TotalSeconds -gt 60) {
+                    throw "Timeout"
+                }
+
+                Start-Sleep -Seconds 1
+            }
+        }
+        finally {
+            $pwsh | Stop-Process -Force -ErrorAction Ignore
+        }
+
+        $err = Get-Item -Path "$testdrive/error" -ErrorAction Ignore
+        $err | Should -BeNullOrEmpty -Because $err
+        $out = Get-Item -Path "$testdrive/out" -ErrorAction Ignore
+        $out | Should -Not -BeNullOrEmpty
+    }
 }
 
 Describe "Native Command Processor" -tags "Feature" {