PowerShell · adityapatwardhan · Apr 8, 2020 · Dec 5, 2019 · Dec 6, 2019 · Dec 6, 2019
@@ -6,6 +6,7 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Management.Automation;
+using System.Management.Automation.Remoting;
 using System.Management.Automation.Runspaces;
 
 using Microsoft.PowerShell.Commands.Internal.Format;
@@ -97,9 +98,28 @@ private static Dictionary<string, List<string>> GetTypeGroupMap(IEnumerable<Type
         /// </summary>
         protected override void ProcessRecord()
         {
-            bool writeOldWay = PowerShellVersion == null ||
-                               PowerShellVersion.Major < 5 ||
-                               (PowerShellVersion.Major == 5 && PowerShellVersion.Minor < 1);
+            // Remoting detection: 
+            //   * Automatic variable $PSSenderInfo is defined in true remoting contexts as well as in background jobs.
+            //   * $PSSenderInfo.ApplicationArguments.PSVersionTable.PSVersion contains the client version, as a [version] instance.
+            //      Note: Even though $PSVersionTable.PSVersion is of type [semver] in PowerShell 6+, it is of type [version] here,
+            //            presumably because only the latter type deserializes type-faithfully.
+            var clientVersion = PowerShellVersion;
+            PSSenderInfo remotingClientInfo = GetVariableValue("PSSenderInfo") as PSSenderInfo;
+            if (clientVersion == null && remotingClientInfo != null)
+            {
+                clientVersion = PSObject.Base((PSObject.Base(remotingClientInfo.ApplicationArguments["PSVersionTable"]) as PSPrimitiveDictionary)?["PSVersion"]) as Version;
+            }
+
+            // During remoting, remain compatible with v5.0- clients by default.
+            // Passing a -PowerShellVersion argument allows overriding the client version.
+            bool writeOldWay = 
+                (remotingClientInfo != null && clientVersion == null)  // To be safe: Remoting client version could unexpectedly not be determined.
+                || 
+                (clientVersion != null
+                    &&
+                    (clientVersion.Major < 5
+                        ||
+                    (clientVersion.Major == 5 && clientVersion.Minor < 1)));
 
             TypeInfoDataBase db = this.Context.FormatDBManager.Database;
 

@@ -14,6 +14,7 @@
 using System.Management.Automation.Configuration;
 using System.Management.Automation.Internal;
 using System.Management.Automation.Language;
+using System.Management.Automation.Remoting;
 using System.Management.Automation.Runspaces;
 using System.Management.Automation.Security;
 using System.Numerics;
@@ -2098,6 +2099,25 @@ public static bool TestImplicitRemotingBatching(string commandPipeline, System.M
         {
             return Utils.TryRunAsImplicitBatch(commandPipeline, runspace);
         }
+
+        /// <summary>
+        /// Constructs a custom PSSenderInfo instance that can be assigned to $PSSenderInfo
+        /// in order to simulate a remoting session with respect to the $PSSenderInfo.ConnectionString (connection URL)
+        /// and $PSSenderInfo.ApplicationArguments.PSVersionTable.PSVersion (the remoting client's PowerShell version).
+        /// See Get-FormatDataTest.ps1.
+        /// </summary>
+        /// <param name="url">The connection URL to reflect in the returned instance's ConnectionString property.</param>
+        /// <param name="clientVersion">The version number to report as the remoting client's PowerShell version.</param>
+        /// <returns>The newly constructed custom PSSenderInfo instance.</returns>
+        public static PSSenderInfo GetCustomPSSenderInfo(string url, Version clientVersion)
+        {
+            var dummyPrincipal = new PSPrincipal(new PSIdentity("none", true, "someuser", null), null);
+            var pssi = new PSSenderInfo(dummyPrincipal, url);
+            pssi.ApplicationArguments = new PSPrimitiveDictionary();
+            pssi.ApplicationArguments.Add("PSVersionTable", new PSObject(new PSPrimitiveDictionary()));
+            ((PSPrimitiveDictionary)PSObject.Base(pssi.ApplicationArguments["PSVersionTable"])).Add("PSVersion", new PSObject(clientVersion));
+            return pssi;
+        }
     }
 
     /// <summary>

@@ -2,7 +2,8 @@
 # Licensed under the MIT License.
 Describe "Export-FormatData" -Tags "CI" {
     BeforeAll {
-        $fd = Get-FormatData
+        $clientVersion = '5.0' # Preliminarily preserve the original test semantics in place before https://github.com/PowerShell/PowerShell/pull/11270
+        $fd = Get-FormatData -PowerShellVersion $clientVersion
         $testOutput = Join-Path -Path $TestDrive -ChildPath "outputfile"
     }
 
@@ -23,7 +24,7 @@ Describe "Export-FormatData" -Tags "CI" {
             $runspace.Open()
 
             $runspace.CreatePipeline("Update-FormatData -AppendPath $TESTDRIVE\allformat.ps1xml").Invoke()
-            $actualAllFormat = $runspace.CreatePipeline("Get-FormatData -TypeName *").Invoke()
+            $actualAllFormat = $runspace.CreatePipeline("Get-FormatData -PowerShellVersion $clientVersion").Invoke()
 
             $fd.Count | Should -Be $actualAllFormat.Count
             Compare-Object $fd $actualAllFormat | Should -Be $null

@@ -3,24 +3,64 @@
 Describe "Get-FormatData" -Tags "CI" {
 
     Context "Check return type of Get-FormatData" {
-
         It "Should return an object[] as the return type" {
             $result = Get-FormatData
-            ,$result | Should -BeOfType System.Object[]
+            , $result | Should -BeOfType "System.Object[]"
         }
     }
 
-    It "Can get format data requiring '-PowerShellVersion 5.1'" {
-        $format = Get-FormatData System.IO.FileInfo -PowerShellVersion 5.1
-        $format.TypeNames | Should -HaveCount 2
-        $format.TypeNames[0] | Should -BeExactly "System.IO.DirectoryInfo"
-        $format.TypeNames[1] | Should -BeExactly "System.IO.FileInfo"
+    # Note: Format data for [System.IO.FileInfo] (among others) is not to be
+    #       returned to v5.0- remoting clients.
+
+    Context "Local use: Can get format data requiring v5.1+ by default" {
+        BeforeAll {
+            $cmds = @(
+                @{ cmd = { Get-FormatData System.IO.FileInfo } }
+                @{ cmd = { (Get-FormatData System.IO.FileInfo &) | Receive-Job -Wait -AutoRemoveJob } }
+            )
+        }
+        It "Can get format data requiring v5.1+ with <cmd>" -TestCases $cmds {
+            param([scriptblock] $cmd)
+            $format = & $cmd
+            $format.TypeNames | Should -HaveCount 2
+            $format.TypeNames[0] | Should -BeExactly "System.IO.DirectoryInfo"
+            $format.TypeNames[1] | Should -BeExactly "System.IO.FileInfo"
 
-        $isUnixStatEnabled = $EnabledExperimentalFeatures -contains 'PSUnixFileStat'
-        $format.FormatViewDefinition | Should -HaveCount ( $isUnixStatEnabled ? 5 : 4)
+            $isUnixStatEnabled = $EnabledExperimentalFeatures -contains 'PSUnixFileStat'
+            $format.FormatViewDefinition | Should -HaveCount ($isUnixStatEnabled ? 5 : 4)
+        }
     }
 
-    It "Should return nothing for format data requiring '-PowerShellVersion 5.1' and not provided" {
-        Get-FormatData System.IO.FileInfo | Should -BeNullOrEmpty
+    Context "Can override client version with -PowerShellVersion" {
+        BeforeAll {
+            $cmds = @(
+                @{ shouldBeNull = $true; cmd = { Get-FormatData System.IO.FileInfo -PowerShellVersion 5.0 } }
+                @{ shouldBeNull = $false; cmd = { Get-FormatData System.IO.FileInfo -PowerShellVersion 5.1 } }
+                @{ shouldBeNull = $false; cmd = { $PSSenderInfo = [System.Management.Automation.Internal.InternalTestHooks]::GetCustomPSSenderInfo('foo', [version] '5.0'); Get-FormatData System.IO.FileInfo -PowerShellVersion 5.1 } }
+            )
+        }
+        It "<cmd> should return <shouldBeNull> for a null-output test" -TestCases $cmds {
+            param([scriptblock] $cmd, [bool] $shouldBeNull)
+            $null -eq $(& $cmd) | Should -Be $shouldBeNull
+        }
     }
+
+    Context "Remote use: By default, don't get format data requiring v5.1+ for v5.0- clients" {
+        BeforeAll {
+            # Simulated PSSenderInfo instances for various PowerShell versions.
+            $pssiV50 = [System.Management.Automation.Internal.InternalTestHooks]::GetCustomPSSenderInfo('foo', [version] '5.0')
+            $pssiV51 = [System.Management.Automation.Internal.InternalTestHooks]::GetCustomPSSenderInfo('foo', [version] '5.1')
+            $pssiV70 = [System.Management.Automation.Internal.InternalTestHooks]::GetCustomPSSenderInfo('foo', [version] '7.0')
+            $cmds = @(
+                @{ shouldBeNull = $true; cmd = { $PSSenderInfo = $pssiV50; Get-FormatData System.IO.FileInfo } }
+                @{ shouldBeNull = $false; cmd = { $PSSenderInfo = $pssiV51; Get-FormatData System.IO.FileInfo } }
+                @{ shouldBeNull = $false; cmd = { $PSSenderInfo = $pssiV70; Get-FormatData System.IO.FileInfo } }
+            )
+        }
+        It "When remoting, <cmd> should return <shouldBeNull> for a null-output test" -TestCases $cmds {
+            param([scriptblock] $cmd, [bool] $shouldBeNull)
+            $null -eq $(& $cmd) | Should -Be $shouldBeNull
+        }
+    }
+
 }