Fix for including ProgressPreference built-in variable in the list of approved uninitialized variables

Engine/SpecialVars.cs

@@ -91,6 +91,7 @@ static SpecialVars()
         internal const string WhatIfPreference = "WhatIfPreference";
         internal const string WarningPreference = "WarningPreference";
         internal const string ConfirmPreference = "ConfirmPreference";
+        internal const string ProgressPreference = "ProgressPreference";
 
         internal static readonly string[] PreferenceVariables = new string[]  
                                                                 {  
@@ -99,7 +100,8 @@ static SpecialVars()
                                                                     ErrorActionPreference,  
                                                                     WhatIfPreference,  
                                                                     WarningPreference,  
-                                                                    ConfirmPreference,  
+                                                                    ConfirmPreference,
+                                                                    ProgressPreference
                                                                 };
 
         internal static readonly Type[] PreferenceVariableTypes = new Type[]  
@@ -109,7 +111,8 @@ static SpecialVars()
                                                                     /* ErrorPreference */   typeof(ActionPreference),  
                                                                     /* WhatIfPreference */  typeof(SwitchParameter),  
                                                                     /* WarningPreference */ typeof(ActionPreference),  
-                                                                    /* ConfirmPreference */ typeof(ConfirmImpact),  
+                                                                    /* ConfirmPreference */ typeof(ConfirmImpact), 
+                                                                    /* ProgressPreference */ typeof(Enum),
                                                                 };
 
         internal enum AutomaticVariable

Tests/Rules/AvoidUsingUninitializedVariable.Tests.ps1

@@ -0,0 +1,24 @@
+Import-Module PSScriptAnalyzer
+$AvoidUninitializedVariable = "PSAvoidUninitializedVariable"
+$violationMessage = "Variable 'MyProgressPreference' is not initialized. Non-global variables must be initialized. To fix a violation of this rule, please initialize non-global variables."
+$directory = Split-Path -Parent $MyInvocation.MyCommand.Path
+$violations = Invoke-ScriptAnalyzer $directory\AvoidUsingUninitializedVariable.ps1 -IncludeRule $AvoidUninitializedVariable
+$noViolations = Invoke-ScriptAnalyzer $directory\AvoidUsingUninitializedVariableNoViolations.ps1 -IncludeRule $AvoidUninitializedVariable
+
+Describe "AvoidUsingUninitializedVariable" {
+    Context "Script uses uninitialized variables - Violation" {
+        It "Have 3 rule violations" {
+            $violations.Count | Should Be 3
+        }
+
+        It "has the correct description message for UninitializedVariable rule violation" {
+            $violations[0].Message | Should Be $violationMessage            
+        }
+    }
+
+    Context "Script uses initialized variables - No violation" {
+        It "results in no rule violations" {
+            $noViolations.Count | Should Be 0
+        }
+    }
+}

Tests/Rules/AvoidUsingUninitializedVariable.ps1

@@ -0,0 +1,10 @@
+# Script has uninitialized variables
+# Must result in AvoidUsingUninitializedVariablerule violations along with other violations
+
+function Test-MyPreference
+{
+    Write-Verbose $MyProgressPreference
+    Write-Verbose $MyVerbosePreference
+}
+
+Write-Verbose $MyProgressPreference

Tests/Rules/AvoidUsingUninitializedVariableNoViolations.ps1

@@ -0,0 +1,11 @@
+# Script uses built-in preference variables
+# Must not result in AvoidUsingUninitializedVariablerule violations
+# However there are other violations in this script - Write-Verbose is not using positional parameters
+
+function Test-Preference
+{
+    Write-Verbose $ProgressPreference
+    Write-Verbose $VerbosePreference
+}
+
+Write-Verbose $ProgressPreference