PowerShell · powercode · Oct 14, 2022 · Oct 14, 2022 · Oct 14, 2022 · Oct 14, 2022
diff --git a/...werShell.Commands.Utility/commands/utility/FormatAndOutput/format-object/Format-Object.cs b/...werShell.Commands.Utility/commands/utility/FormatAndOutput/format-object/Format-Object.cs
@@ -31,40 +31,31 @@ public FormatCustomCommand()
         /// will be determined using property sets, etc.
         /// </summary>
         [Parameter(Position = 0)]
-        public object[] Property
-        {
-            get { return _props; }
-
-            set { _props = value; }
-        }
-
-        private object[] _props;
+        public object[] Property { get; set; }
 
         /// <summary>
+        /// Specifies the number of levels to recurse complex properties
         /// </summary>
-        /// <value></value>
         [ValidateRangeAttribute(1, int.MaxValue)]
         [Parameter]
-        public int Depth
-        {
-            get { return _depth; }
-
-            set { _depth = value; }
-        }
+        public int Depth { get; set; } = ComplexSpecificParameters.maxDepthAllowable;
 
-        private int _depth = ComplexSpecificParameters.maxDepthAllowable;
+        /// <inheritdoc cref="ComplexSpecificParameters.ScalarTypesToExpand" />
+        [Parameter]
+        [ValidateSet("System.DateTime", "System.DateTimeOffset")] // if we get more types here, consider moving to IValidateSetValuesGenerator
+        public string[] ExpandType { get; set; }
 
         #endregion
 
         internal override FormattingCommandLineParameters GetCommandLineParameters()
         {
             FormattingCommandLineParameters parameters = new();
 
-            if (_props != null)
+            if (Property != null)
             {
                 ParameterProcessor processor = new(new FormatObjectParameterDefinition());
                 TerminatingErrorContext invocationContext = new(this);
-                parameters.mshParameterList = processor.ProcessParameters(_props, invocationContext);
+                parameters.mshParameterList = processor.ProcessParameters(Property, invocationContext);
             }
 
             if (!string.IsNullOrEmpty(this.View))
@@ -88,7 +79,8 @@ internal override FormattingCommandLineParameters GetCommandLineParameters()
             parameters.expansion = ProcessExpandParameter();
 
             ComplexSpecificParameters csp = new();
-            csp.maxDepth = _depth;
+            csp.maxDepth = Depth;
+            csp.ScalarTypesToExpand = ExpandType;
             parameters.shapeParameters = csp;
 
             return parameters;

diff --git a/src/System.Management.Automation/FormatAndOutput/common/BaseFormattingCommandParameters.cs b/src/System.Management.Automation/FormatAndOutput/common/BaseFormattingCommandParameters.cs
@@ -105,6 +105,17 @@ internal enum ClassInfoDisplay { none, fullName, shortName }
         /// Max depth of recursion on sub objects.
         /// </summary>
         internal int maxDepth = maxDepthAllowable;
+
+        /// <summary>
+        /// Gets or sets an array of type names that are by default rendered as scalar, but should be expanded.
+        /// </summary>
+        internal string[] ScalarTypesToExpand
+        {
+            get => _scalarTypesToExpand ?? Array.Empty<string>();
+            set => _scalarTypesToExpand = value;
+        }
+
+        private string[] _scalarTypesToExpand;
     }
 
     #endregion

diff --git a/src/System.Management.Automation/FormatAndOutput/common/FormatViewGenerator_Complex.cs b/src/System.Management.Automation/FormatAndOutput/common/FormatViewGenerator_Complex.cs
@@ -418,6 +418,12 @@ internal TraversalInfo NextLevel
     /// </summary>
     internal sealed class ComplexViewObjectBrowser
     {
+        private static readonly HashSet<string> s_defaultLeafTypes = new(System.StringComparer.OrdinalIgnoreCase) 
+        { 
+            "System.DateTime", 
+            "System.DateTimeOffset" 
+        };
+
         internal ComplexViewObjectBrowser(FormatErrorManager resultErrorManager, PSPropertyExpressionFactory mshExpressionFactory, int enumerationLimit)
         {
             _errorManager = resultErrorManager;
@@ -445,7 +451,7 @@ internal ComplexViewEntry GenerateView(PSObject so, FormattingCommandLineParamet
             // create a top level entry as root of the tree
             ComplexViewEntry cve = new ComplexViewEntry();
             var typeNames = so.InternalTypeNames;
-            if (TreatAsScalarType(typeNames))
+            if (TreatAsScalarType(typeNames, _complexSpecificParameters.ScalarTypesToExpand))
             {
                 FormatEntry fe = new FormatEntry();
 
@@ -589,7 +595,7 @@ private void ProcessActiveAssociationList(PSObject so,
                     formatValueList.Add(new FormatNewLine());
                     DisplayEnumeration(e, level.NextLevel, AddIndentationLevel(formatValueList));
                 }
-                else if (val == null || TreatAsLeafNode(val, level))
+                else if (val == null || TreatAsLeafNode(val, level, _complexSpecificParameters.ScalarTypesToExpand))
                 {
                     DisplayLeaf(val, formatValueList);
                 }
@@ -640,7 +646,7 @@ private void DisplayEnumerationInner(IEnumerable e, TraversalInfo level, List<Fo
                     enumCount++;
                 }
 
-                if (TreatAsLeafNode(x, level))
+                if (TreatAsLeafNode(x, level, _complexSpecificParameters.ScalarTypesToExpand))
                 {
                     DisplayLeaf(x, formatValueList);
                 }
@@ -681,23 +687,46 @@ private void DisplayLeaf(object val, List<FormatValue> formatValueList)
         /// </summary>
         /// <param name="val">Object to verify.</param>
         /// <param name="level">Current level of recursion.</param>
-        /// <returns></returns>
-        private static bool TreatAsLeafNode(object val, TraversalInfo level)
+        /// <param name="scalarTypesToExpand">Array of names of types that should not be rendered as scalars.</param>
+        /// <returns>True if it has to be treated as leaf node.</returns>
+        private static bool TreatAsLeafNode(object val, TraversalInfo level, string[] scalarTypesToExpand)
         {
             if (level.Level >= level.MaxDepth || val == null)
+            {
                 return true;
+            }
 
-            return TreatAsScalarType(PSObject.GetTypeNames(val));
+            return TreatAsScalarType(PSObject.GetTypeNames(val), scalarTypesToExpand);
         }
 
         /// <summary>
         /// Treat as scalar check.
         /// </summary>
         /// <param name="typeNames">Name of the type to check.</param>
+        /// <param name="scalarTypesToExpand">Array of names of types that should not be rendered as scalars.</param>
         /// <returns>True if it has to be treated as a scalar.</returns>
-        private static bool TreatAsScalarType(Collection<string> typeNames)
+        private static bool TreatAsScalarType(Collection<string> typeNames, string[] scalarTypesToExpand)
+        {
+            return DefaultScalarTypes.IsTypeInList(typeNames) || TypeIsScalarForComplexView(typeNames, scalarTypesToExpand);
+        }
+
+        private static bool TypeIsScalarForComplexView(Collection<string> typeNames, string[] scalarTypesToExpand)
         {
-            return DefaultScalarTypes.IsTypeInList(typeNames);
+            foreach (var type in typeNames)
+            {
+                // if the type is in the scalarTypesToExpand, we should not treat it as a scalar
+                if (s_defaultLeafTypes.Contains(type))
+                {
+                    if (System.Array.Find(scalarTypesToExpand, t => t == type) is not null)
+                    {
+                        return false;
+                    }
+
+                    return true;
+                }
+            }
+
+            return false;
         }
 
         private string GetObjectDisplayName(PSObject so)

diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Format-Custom.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Format-Custom.Tests.ps1
@@ -23,6 +23,63 @@ Describe "Format-Custom" -Tags "CI" {
         }
 
     }
+
+    Context "Treats datetime as scalar unless Expanded" {
+        BeforeAll{
+            $date = [DateTime]::new(2000,01,02)
+            $obj = [PSCustomObject] @{
+                Date = $date
+                PSTypeName="DateTimeTest"
+            }
+            # locale aware formatting
+            $dateStr = $date.ToString()
+            $shortDate = $date.Date.ToString()
+            $longDate = $date.ToString("F")
+
+        }
+
+        It "Should treat datetime as scalar by default" {
+            $res = ($obj | Format-Custom | Out-String).Trim()
+            $res | Should -BeExactly @"
+class DateTimeTest
+{
+  Date = $dateStr
+}
+"@
+        }
+
+        It "Treats datetime as non-scalar when Expanded" {
+
+          $expected = @"
+class DateTimeTest
+{
+  Date =
+    class DateTime
+    {
+          Date = $shortDate
+      Day = 2
+      DayOfWeek = Sunday
+      DayOfYear = 2
+      Hour = 0
+      Kind = Unspecified
+      Millisecond = 0
+      Microsecond = 0
+      Nanosecond = 0
+      Minute = 0
+      Month = 1
+      Second = 0
+      Ticks = 630823680000000000
+      TimeOfDay = 00:00:00
+      Year = 2000
+      DateTime = $longDate
+    }
+}
+"@ -replace 'Date =\r?\n', "Date = `n" -replace '\r\n', "`n" # the 'Date = ' replacement is needed as editors trim whitespace at the end of lines.
+
+            $actual = ($obj | Format-Custom -ExpandType:System.DateTime -Depth:1 | Out-String).Trim() -replace '\r?\n', "`n"
+            $actual | Should -BeExactly $expected
+        }
+    }
 }
 
 Describe "Format-Custom DRT basic functionality" -Tags "CI" {