Remove nullable from typename for inputs and outputs

src/Transform/TransformBase.cs

@@ -100,7 +100,8 @@ commandInfo is CmdletInfo ||
         // We can also simplify the string if desired.
         private string GetAdjustedTypename(Type t, bool simplify = false)
         {
-            string tName = simplify ?  LanguagePrimitives.ConvertTo<string>(t) : t.FullName;
+            var t2 = Nullable.GetUnderlyingType(t) ?? t;
+            string tName = simplify ?  LanguagePrimitives.ConvertTo<string>(t2) : t2.FullName;
             return tName;
         }
 
@@ -847,7 +848,14 @@ protected List<InputOutput> GetInputOutputItemsFromHelp(dynamic typesInfo)
         // We also will remove trailing [] because we should generally return singletons
         private string FixUpTypeName(string typename)
         {
-            string fixedString = typename.Trim();
+            // If the type is a generic type, we need to remove the backtick and the number.
+            string fixedString = typename.Replace("System.Nullable`1[[", string.Empty).Trim();
+            int commaIndex = fixedString.IndexOf(',');
+            if (commaIndex >= 0)
+            {
+                fixedString = fixedString.Substring(0, commaIndex).Trim();
+            }
+
             if (fixedString.EndsWith("[]"))
             {
                 fixedString = fixedString.Remove(fixedString.Length - 2);

test/Pester/ConvertToCommandHelp.Tests.ps1

@@ -141,6 +141,20 @@ Describe "New-CommandHelp tests" {
         BeforeAll {
             $cmd = Get-Command Get-Command
             $ch = $cmd | New-CommandHelp
+
+            function global:Test-InputOutputTypes
+            {
+                [CmdletBinding()]
+                [OutputType()]
+                param(
+                    [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
+                    [Nullable[int]]$InputString
+                )
+
+                Write-Output "Processed: $InputString"
+            }
+
+            $io = New-CommandHelp -Command (Get-Command Test-InputOutputTypes)
         }
 
         It "Should have the proper number of output types" {
@@ -176,12 +190,16 @@ Describe "New-CommandHelp tests" {
             @{ Type = "System.Management.Automation.CommandTypes" }
             @{ Type = "System.Int32" }
             @{ Type = "Microsoft.PowerShell.Commands.ModuleSpecification[]" }
-            @{ Type = "System.String" }
+            @{ Type = "System.String[]" }
             @{ Type = "System.Management.Automation.SwitchParameter" }
         ) {
             param ($type)
             $ch.inputs.typename | Should -Contain $type
         }
-    }
 
+        It "Should not have Nullable in the input type" {
+            $io.inputs.typename | Should -Not -Contain "Nullable"
+            $io.inputs.typename | Should -Be "System.Int32"
+        }
+    }
 }