Filter completion for enum parameter against ValidateRange-attributes

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

@@ -1311,6 +1311,29 @@ private static Type GetCommonType(Type minType, Type maxType)
 
             return resultType;
         }
+
+        /// <summary>
+        /// Returns a list containing only the elements that passed the attribute's validation.
+        /// </summary>
+        /// <param name="elementsToValidate">The objects to validate.</param>
+        internal IList<T> GetValidatedElements<T>(IList<T> elementsToValidate)
+        {
+            var result = new List<T>(elementsToValidate.Count);
+            foreach (var el in elementsToValidate)
+            {
+                try
+                {
+                    ValidateElement(el);
+                    result.Add(el);
+                }
+                catch (ValidationMetadataException)
+                {
+                    // Element was not in range - drop
+                }
+            }
+
+            return result;
+        }
     }
 
     /// <summary>

src/System.Management.Automation/engine/CommandCompletion/CompletionCompleters.cs

@@ -1770,28 +1770,35 @@ private static void ProcessParameter(
             {
                 RemoveLastNullCompletionResult(result);
 
-                string enumString = LanguagePrimitives.EnumSingleTypeConverter.EnumValues(parameterType);
-                string separator = CultureInfo.CurrentUICulture.TextInfo.ListSeparator;
-                string[] enumArray = enumString.Split(separator, StringSplitOptions.RemoveEmptyEntries);
+                IList<Enum> enumValues = LanguagePrimitives.EnumSingleTypeConverter.GetEnumValues(parameterType).Cast<Enum>().ToList();
+                // Exclude values not accepted by ValidateRange-attributes
+                foreach (ValidateArgumentsAttribute att in parameter.Parameter.ValidationAttributes)
+                {
+                    if (att is ValidateRangeAttribute rangeAtt)
+                    {
+                        enumValues = rangeAtt.GetValidatedElements(enumValues);
+                    }
+                }
 
                 string wordToComplete = context.WordToComplete ?? string.Empty;
                 string quote = HandleDoubleAndSingleQuote(ref wordToComplete);
 
                 var pattern = WildcardPattern.Get(wordToComplete + "*", WildcardOptions.IgnoreCase);
                 var enumList = new List<string>();
 
-                foreach (string value in enumArray)
+                foreach (Enum value in enumValues)
                 {
-                    if (wordToComplete.Equals(value, StringComparison.OrdinalIgnoreCase))
+                    string name = value.ToString();
+                    if (wordToComplete.Equals(name, StringComparison.OrdinalIgnoreCase))
                     {
-                        string completionText = quote == string.Empty ? value : quote + value + quote;
-                        fullMatch = new CompletionResult(completionText, value, CompletionResultType.ParameterValue, value);
+                        string completionText = quote == string.Empty ? name : quote + name + quote;
+                        fullMatch = new CompletionResult(completionText, name, CompletionResultType.ParameterValue, name);
                         continue;
                     }
 
-                    if (pattern.IsMatch(value))
+                    if (pattern.IsMatch(name))
                     {
-                        enumList.Add(value);
+                        enumList.Add(name);
                     }
                 }
 

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

@@ -2085,6 +2085,14 @@ internal static string EnumValues(Type enumType)
                 return string.Join(CultureInfo.CurrentUICulture.TextInfo.ListSeparator, enumHashEntry.names);
             }
 
+            /// <summary>
+            /// Returns all values for the provided enum type.
+            /// </summary>
+            /// <param name="enumType">The enum type to retrieve values from.</param>
+            /// <returns>Array of enum values for the specified type.</returns>
+            internal static Array GetEnumValues(Type enumType)
+                => EnumSingleTypeConverter.GetEnumHashEntry(enumType).values;
+
             public override object ConvertFrom(object sourceValue, Type destinationType, IFormatProvider formatProvider, bool ignoreCase)
             {
                 return EnumSingleTypeConverter.BaseConvertFrom(sourceValue, destinationType, formatProvider, ignoreCase, false);

test/powershell/Host/TabCompletion/TabCompletion.Tests.ps1

@@ -1345,6 +1345,31 @@ ConstructorTestClass(int i, bool b)
             $res.CompletionMatches[1].CompletionText | Should -BeExactly 'Configuration'
         }
 
+        It 'Tab completion for enum parameter is filtered against <Name>' -TestCases @(
+            @{ Name = 'ValidateRange with enum-values'; Attribute = '[ValidateRange([System.ConsoleColor]::Blue, [System.ConsoleColor]::Cyan)]' }
+            @{ Name = 'ValidateRange with int-values'; Attribute = '[ValidateRange(9, 11)]' }
+            @{ Name = 'multiple ValidateRange-attributes'; Attribute = '[ValidateRange([System.ConsoleColor]::Blue, [System.ConsoleColor]::Cyan)][ValidateRange([System.ConsoleColor]::Gray, [System.ConsoleColor]::Red)]' }
+        ) {
+            param($Name, $Attribute)
+            $functionDefinition = 'param ( {0}[consolecolor]$color )' -f $Attribute
+            Set-Item -Path function:baz -Value $functionDefinition
+            $inputStr = 'baz -color '
+            $res = TabExpansion2 -inputScript $inputStr -cursorColumn $inputStr.Length
+            $res.CompletionMatches | Should -HaveCount 3
+            $res.CompletionMatches[0].CompletionText | Should -BeExactly 'Blue'
+            $res.CompletionMatches[1].CompletionText | Should -BeExactly 'Cyan'
+            $res.CompletionMatches[2].CompletionText | Should -BeExactly 'Green'
+        }
+
+        It 'Tab completion for enum parameter is filtered with ValidateRange using rangekind' {
+            $functionDefinition = 'param ( [ValidateRange([System.Management.Automation.ValidateRangeKind]::NonPositive)][consolecolor]$color )' -f $Attribute
+            Set-Item -Path function:baz -Value $functionDefinition
+            $inputStr = 'baz -color '
+            $res = TabExpansion2 -inputScript $inputStr -cursorColumn $inputStr.Length
+            $res.CompletionMatches | Should -HaveCount 1
+            $res.CompletionMatches[0].CompletionText | Should -BeExactly 'Black' # 0 = NonPositive
+        }
+
         It "Test [CommandCompletion]::GetNextResult" {
             $inputStr = "Get-Command -Type Alias,c"
             $res = TabExpansion2 -inputScript $inputStr -cursorColumn $inputStr.Length