Normalize behavior of parsing nullable booleans

Author: mythz

src/ServiceStack.Text/Common/DeserializeBuiltin.cs

@@ -37,14 +37,7 @@ private static ParseStringSpanDelegate GetParseStringSpanFn()
                 switch (typeCode)
                 {
                     case TypeCode.Boolean:
-                        //Lots of kids like to use '1', HTML checkboxes use 'on' as a soft convention
-                        return value =>
-                            value.Length == 1 ?
-                              value[0] == '1'
-                            : value.Length == 2 ?
-                              value[0] == 'o' && value[1] == 'n' :
-                              value.ParseBoolean();
-
+                        return value => value.ParseBoolean();
                     case TypeCode.SByte:
                         return SignedInteger<sbyte>.ParseObject;
                     case TypeCode.Byte:
@@ -87,14 +80,9 @@ private static ParseStringSpanDelegate GetParseStringSpanFn()
                 switch (typeCode)
                 {
                     case TypeCode.Boolean:
-                        return value => value.IsNullOrEmpty() ?
-                              (bool?)null
-                            : value.Length == 1 ?
-                              value[0] == '1'
-                            : value.Length == 2 ?
-                              value[0] == 'o' && value[1] == 'n' :
-                              value.ParseBoolean();
-
+                        return value => value.IsNullOrEmpty() 
+                            ? (bool?)null 
+                            : value.ParseBoolean();
                     case TypeCode.SByte:
                         return SignedInteger<sbyte>.ParseNullableObject;
                     case TypeCode.Byte:

src/ServiceStack.Text/StringSpanExtensions.cs

@@ -70,7 +70,42 @@ public static ReadOnlySpan<char> FromCsvField(this ReadOnlySpan<char> text)
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static bool ParseBoolean(this ReadOnlySpan<char> value) => MemoryProvider.Instance.ParseBoolean(value);
+        public static bool ParseBoolean(this ReadOnlySpan<char> value)
+        {
+            //Lots of kids like to use '1', HTML checkboxes use 'on' as a soft convention
+            switch (value.Length)
+            {
+                case 0:
+                    return false;
+                case 1:
+                    switch (value[0])
+                    {
+                        case '1':
+                        case 't':
+                        case 'T':
+                        case 'y':
+                        case 'Y':
+                            return true;
+                        case '0':
+                        case 'f':
+                        case 'F':
+                        case 'n':
+                        case 'N':
+                            return false;
+                    }
+                    break;
+                case 2:
+                    if (value[0] == 'o' && value[1] == 'n')
+                        return true;
+                    break;
+                case 3:
+                    if (value[0] == 'o' && value[1] == 'f' && value[1] == 'f')
+                        return false;
+                    break;
+            }
+
+            return MemoryProvider.Instance.ParseBoolean(value);
+        }
 
         public static bool TryParseBoolean(this ReadOnlySpan<char> value, out bool result) =>
             MemoryProvider.Instance.TryParseBoolean(value, out result);

tests/ServiceStack.Text.Tests/Issues/NullableIssues.cs

@@ -0,0 +1,54 @@
+using NUnit.Framework;
+
+namespace ServiceStack.Text.Tests.Issues
+{
+    public class NullableIssues
+    {
+        public class NBoolTest
+        {
+            public bool? IsOk {get; set;}
+
+            protected bool Equals(NBoolTest other) => IsOk == other.IsOk;
+            public override bool Equals(object obj)
+            {
+                if (ReferenceEquals(null, obj)) return false;
+                if (ReferenceEquals(this, obj)) return true;
+                if (obj.GetType() != this.GetType()) return false;
+                return Equals((NBoolTest) obj);
+            }
+            public override int GetHashCode() => IsOk.GetHashCode();
+        }
+        
+        [Test]
+        public void Does_deserialize_nullable_bools()
+        {
+            Assert.That("{\"IsOk\": true}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = true }));
+            Assert.That("{\"IsOk\": false}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = false }));
+            Assert.That("{\"IsOk\": \"true\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = true }));
+            Assert.That("{\"IsOk\": \"false\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = false }));
+            Assert.That("{\"IsOk\": \"True\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = true }));
+            Assert.That("{\"IsOk\": \"False\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = false }));
+            
+            Assert.That("{\"IsOk\": null}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = null }));
+        }
+        
+        [Test]
+        public void Does_deserialize_nullable_bools_conventions()
+        {
+            Assert.That("{\"IsOk\": \"t\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = true }));
+            Assert.That("{\"IsOk\": \"f\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = false }));
+            Assert.That("{\"IsOk\": \"Y\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = true }));
+            Assert.That("{\"IsOk\": \"N\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = false }));
+            Assert.That("{\"IsOk\": \"on\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = true }));
+            Assert.That("{\"IsOk\": \"off\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = false }));
+        }
+        
+        [Test]
+        public void Deserialize_nullable_bools_results_in_error()
+        {
+            Assert.That("{\"IsOk\": \"tt\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = null }));
+            Assert.That("{\"IsOk\": \"fu\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = null }));
+            Assert.That("{\"IsOk\": \"eee\"}".FromJson<NBoolTest>(), Is.EqualTo(new NBoolTest { IsOk = null }));
+        }
+    }
+}