Win7 OSArchitecture crash workaround (#808)

* Avoid System.Runtime.InteropServices.RuntimeInformation.OSArchitecture in win7 on .NET Framework

* Warn users on lower than .NET 451 that they are not supported

Author: rjmholt

module/PowerShellEditorServices/Start-EditorServices.ps1

@@ -161,6 +161,21 @@ if ($host.Runspace.LanguageMode -eq 'ConstrainedLanguage') {
     ExitWithError "PowerShell is configured with an unsupported LanguageMode (ConstrainedLanguage), language features are disabled."
 }
 
+# net45 is not supported, only net451 and up
+if ($PSVersionTable.PSVersion.Major -le 5) {
+    $net451Version = 378675
+    $dotnetVersion = (Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\").Release
+    if ($dotnetVersion -lt $net451Version) {
+        Write-SessionFile @{
+            status = failed
+            reason = "netversion"
+            detail = "$netVersion"
+        }
+
+        ExitWithError "Your .NET version is too low. Upgrade to net451 or higher to run the PowerShell extension."
+    }
+}
+
 # If PSReadline is present in the session, remove it so that runspace
 # management is easier
 if ((Microsoft.PowerShell.Core\Get-Module PSReadline).Count -gt 0) {

src/PowerShellEditorServices.Host/EditorServicesHost.cs

@@ -154,6 +154,8 @@ public void StartLogging(string logFilePath, LogLevel logLevel)
 
             string osVersion = RuntimeInformation.OSDescription;
 
+            string osArch = GetOSArchitecture();
+
             string buildTime = BuildInfo.BuildTime?.ToString("s", System.Globalization.CultureInfo.InvariantCulture) ?? "<unspecified>";
 
             string logHeader = $@"
@@ -164,12 +166,12 @@ public void StartLogging(string logFilePath, LogLevel logLevel)
     Name:      {this.hostDetails.Name}
     Version:   {this.hostDetails.Version}
     ProfileId: {this.hostDetails.ProfileId}
-    Arch:      {RuntimeInformation.OSArchitecture}
+    Arch:      {osArch}
 
   Operating system details:
 
     Version: {osVersion}
-    Arch:    {RuntimeInformation.OSArchitecture}
+    Arch:    {osArch}
 
   Build information:
 
@@ -245,7 +247,7 @@ await this.editorSession.PowerShellContext.ImportCommandsModule(
             // gets initialized when that is done earlier than LanguageServer.Initialize
             foreach (string module in this.additionalModules)
             {
-                var command = 
+                var command =
                     new System.Management.Automation.PSCommand()
                         .AddCommand("Microsoft.PowerShell.Core\\Import-Module")
                         .AddParameter("Name", module);
@@ -493,6 +495,28 @@ private IServerListener CreateServiceListener(MessageProtocolType protocol, Edit
             }
         }
 
+        /// <summary>
+        /// Gets the OSArchitecture for logging. Cannot use System.Runtime.InteropServices.RuntimeInformation.OSArchitecture
+        /// directly, since this tries to load API set DLLs in win7 and crashes.
+        ///
+        /// <returns></returns>
+        private string GetOSArchitecture()
+        {
+#if !CoreCLR
+            // If on win7 (version 6.1.x), avoid System.Runtime.InteropServices.RuntimeInformation
+            if (Environment.OSVersion.Platform == PlatformID.Win32NT && Environment.OSVersion.Version < new Version(6, 2))
+            {
+                if (Environment.Is64BitProcess)
+                {
+                    return "X64";
+                }
+
+                return "X86";
+            }
+#endif
+            return RuntimeInformation.OSArchitecture.ToString();
+        }
+
         #endregion
     }
 }