Add raw value validation to multiple text strings property editor (#18936)

* Add raw value validation to multiple text strings property editor

* Added additional assert on unit test and comment on validation logic.

* Don't remove items to obtain a valid value

---------

Co-authored-by: Andy Butland <abutland73@gmail.com>

src/Umbraco.Infrastructure/PropertyEditors/MultipleTextStringPropertyEditor.cs

@@ -89,21 +89,6 @@ public class MultipleTextStringPropertyEditor : DataEditor
                 return null;
             }
 
-            if (!(editorValue.DataTypeConfiguration is MultipleTextStringConfiguration config))
-            {
-                throw new PanicException(
-                    $"editorValue.DataTypeConfiguration is {editorValue.DataTypeConfiguration?.GetType()} but must be {typeof(MultipleTextStringConfiguration)}");
-            }
-
-            var max = config.Max;
-
-            // The legacy property editor saved this data as new line delimited! strange but we have to maintain that.
-            // only allow the max if over 0
-            if (max > 0)
-            {
-                return string.Join(_newLine, value.Take(max));
-            }
-
             return string.Join(_newLine, value);
         }
 
@@ -114,9 +99,12 @@ public class MultipleTextStringPropertyEditor : DataEditor
 
             // The legacy property editor saved this data as new line delimited! strange but we have to maintain that.
             return value is string stringValue
-                ? stringValue.Split(_newLineDelimiters, StringSplitOptions.None)
+                ? SplitPropertyValue(stringValue)
                 : Array.Empty<string>();
         }
+
+        internal static string[] SplitPropertyValue(string propertyValue)
+            => propertyValue.Split(_newLineDelimiters, StringSplitOptions.None);
     }
 
     /// <summary>
@@ -166,13 +154,13 @@ public class MultipleTextStringPropertyEditor : DataEditor
                 yield break;
             }
 
-            // If we have a null value, treat as an empty collection for minimum number validation.
-            if (value is not IEnumerable<string> stringValues)
-            {
-                stringValues = [];
-            }
-
-            var stringCount = stringValues.Count();
+            // Handle both a newline delimited string and an IEnumerable<string> as the value (see: https://github.com/umbraco/Umbraco-CMS/pull/18936).
+            // If we have a null value, treat as a string count of zero for minimum number validation.
+            var stringCount = value is string stringValue
+                ? MultipleTextStringPropertyValueEditor.SplitPropertyValue(stringValue).Length
+                : value is IEnumerable<string> strings
+                    ? strings.Count()
+                    : 0;
 
             if (stringCount < multipleTextStringConfiguration.Min)
             {

tests/Umbraco.Tests.UnitTests/Umbraco.Core/PropertyEditors/MultipleTextStringPropertyValueEditorTests.cs

@@ -82,6 +82,20 @@ public class MultipleTextStringPropertyValueEditorTests
         Assert.AreEqual("The First Value\nThe Second Value\nThe Third Value", fromEditor);
     }
 
+    [Test]
+    public void Can_Parse_More_Items_Than_Allowed_From_Editor()
+    {
+        var valueEditor = CreateValueEditor();
+        var fromEditor = valueEditor.FromEditor(new ContentPropertyData(new[] { "One", "Two", "Three", "Four", "Five" }, new MultipleTextStringConfiguration { Max = 4 }), null) as string;
+        Assert.AreEqual("One\nTwo\nThree\nFour\nFive", fromEditor);
+
+        var validationResults = valueEditor.Validate(fromEditor, false, null, PropertyValidationContext.Empty());
+        Assert.AreEqual(1, validationResults.Count());
+
+        var validationResult = validationResults.First();
+        Assert.AreEqual($"validation_outOfRangeMultipleItemsMaximum", validationResult.ErrorMessage);
+    }
+
     [Test]
     public void Can_Parse_Single_Value_To_Editor()
     {
@@ -150,6 +164,27 @@ public class MultipleTextStringPropertyValueEditorTests
         }
     }
 
+    [TestCase("", false)]
+    [TestCase("one", false)]
+    [TestCase("one\ntwo", true)]
+    [TestCase("one\ntwo\nthree", true)]
+    public void Validates_Number_Of_Items_Is_Greater_Than_Or_Equal_To_Configured_Min_Raw_Property_Value(string value, bool expectedSuccess)
+    {
+        var editor = CreateValueEditor();
+        var result = editor.Validate(value, false, null, PropertyValidationContext.Empty());
+        if (expectedSuccess)
+        {
+            Assert.IsEmpty(result);
+        }
+        else
+        {
+            Assert.AreEqual(1, result.Count());
+
+            var validationResult = result.First();
+            Assert.AreEqual($"validation_outOfRangeSingleItemMinimum", validationResult.ErrorMessage);
+        }
+    }
+
     [TestCase(3, true)]
     [TestCase(4, true)]
     [TestCase(5, false)]
@@ -171,6 +206,36 @@ public class MultipleTextStringPropertyValueEditorTests
         }
     }
 
+    [TestCase("one\ntwo\nthree", true)]
+    [TestCase("one\ntwo\nthree\nfour", true)]
+    [TestCase("one\ntwo\nthree\nfour\nfive", false)]
+    public void Validates_Number_Of_Items_Is_Less_Than_Or_Equal_To_Configured_Max_Raw_Property_Value(string value, bool expectedSuccess)
+    {
+        var editor = CreateValueEditor();
+        var result = editor.Validate(value, false, null, PropertyValidationContext.Empty());
+        if (expectedSuccess)
+        {
+            Assert.IsEmpty(result);
+        }
+        else
+        {
+            Assert.AreEqual(1, result.Count());
+
+            var validationResult = result.First();
+            Assert.AreEqual("validation_outOfRangeMultipleItemsMaximum", validationResult.ErrorMessage);
+        }
+    }
+
+    [TestCase("one\ntwo\nthree")]
+    [TestCase("one\rtwo\rthree")]
+    [TestCase("one\r\ntwo\r\nthree")]
+    public void Can_Parse_Supported_Property_Value_Delimiters(string value)
+    {
+        var editor = CreateValueEditor();
+        var result = editor.Validate(value, false, null, PropertyValidationContext.Empty());
+        Assert.IsEmpty(result);
+    }
+
     [Test]
     public void Max_Item_Validation_Respects_0_As_Unlimited()
     {