fix: custom name fetch on null instances (#11)

maranmaran · Jul 18, 2023 · 0d4597c · 0d4597c
1 parent 1cf3b9f
commit 0d4597c
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Showing 4 changed files with 58 additions and 13 deletions.
diff --git a/source/Directory.Build.props b/source/Directory.Build.props
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project>
   <PropertyGroup>
-    <Version>2.1.2</Version>
+    <Version>2.1.3</Version>
     <Authors>Marko Urh</Authors>
     <Company>Perun</Company>
     <Copyright>Copyright (c) 2023 Marko Urh and other authors.</Copyright>

diff --git a/source/Perun.Differ.Tests/DifferTests.cs b/source/Perun.Differ.Tests/DifferTests.cs
@@ -70,33 +70,36 @@ public void Complex_Diffs()
         [Fact]
         public void Nulls_Diffs()
         {
-            var entity = new AutoFaker<SimpleTypes>().UseSeed(1).Generate();
-            var entity2 = new AutoFaker<ComplexType>().UseSeed(1).Generate();
-            var entity3 = new AutoFaker<SimpleIterableTypes>().UseSeed(1).Generate();
-            var entity4 = new AutoFaker<ComplexIterableTypes>().UseSeed(1).Generate();
-
             var diffsNone = DifferDotNet.Diff<SimpleTypes>(null, null).ToList();
             Assert.Empty(diffsNone);
 
+            var entity = new AutoFaker<SimpleTypes>().UseSeed(1).Generate();
             var diffsRight = DifferDotNet.Diff(null, entity).ToList();
             var diffsLeft = DifferDotNet.Diff(entity, null).ToList();
             Assert.NotEmpty(diffsRight);
             Assert.NotEmpty(diffsLeft);
 
+            var entity2 = new AutoFaker<ComplexType>().UseSeed(1).Generate();
             diffsRight = DifferDotNet.Diff(null, entity2).ToList();
             diffsLeft = DifferDotNet.Diff(entity2, null).ToList();
             Assert.NotEmpty(diffsRight);
             Assert.NotEmpty(diffsLeft);
 
+            var entity3 = new AutoFaker<SimpleIterableTypes>().UseSeed(1).Generate();
             diffsRight = DifferDotNet.Diff(null, entity3).ToList();
             diffsLeft = DifferDotNet.Diff(entity3, null).ToList();
             Assert.NotEmpty(diffsRight);
             Assert.NotEmpty(diffsLeft);
 
+            var entity4 = new AutoFaker<ComplexIterableTypes>().UseSeed(1).Generate();
             diffsRight = DifferDotNet.Diff(null, entity4).ToList();
             diffsLeft = DifferDotNet.Diff(entity4, null).ToList();
             Assert.NotEmpty(diffsRight);
             Assert.NotEmpty(diffsLeft);
+
+            entity4 = new ComplexIterableTypes { Array = null };
+            diffsNone = DifferDotNet.Diff(entity4, entity4).ToList();
+            Assert.Empty(diffsNone);
         }
 
         [Fact]
@@ -691,6 +694,20 @@ public void CustomNameDefined_Reflection_RegisteredInDiff()
             Assert.Equal("a", diff.FieldName);
         }
 
+        [Fact]
+        public void CustomNameDefined_Reflection_NullInstance_ReturnsDiff()
+        {
+            var faker = new AutoFaker<CustomNameNullValueReflectionModelNested>();
+            var faker2 = new AutoFaker<CustomNameNullValueReflectionModel>();
+
+            var left = new CustomNameNullValueReflectionModelNested() { Items = null };
+            var right = faker.UseSeed(2).Generate();
+
+            var diff = DifferDotNet.Diff(left, right);
+
+            Assert.NotEmpty(diff);
+        }
+
         [Fact]
         public void CustomNameDefined_RegisteredInDiff()
         {

diff --git a/source/Perun.Differ.Tests/TestTypes/CustomNameModels.cs b/source/Perun.Differ.Tests/TestTypes/CustomNameModels.cs
@@ -1,4 +1,6 @@
-namespace Differ.DotNet.Tests.TestTypes
+using System.Collections.Generic;
+
+namespace Differ.DotNet.Tests.TestTypes
 {
     internal class CustomNameModel
     {
@@ -16,6 +18,19 @@ internal class CustomNameReflectionModel
         public string B => "MyCustomName";
     }
 
+    internal class CustomNameNullValueReflectionModel
+    {
+        [DiffPropertyName("B", fromPropertyValue: true)]
+        public double? A { get; set; }
+
+        public string B => "MyCustomName";
+    }
+
+    internal class CustomNameNullValueReflectionModelNested
+    {
+        public List<CustomNameNullValueReflectionModel> Items { get; set; }
+    }
+
     internal class CustomNameNestedModel
     {
         [DiffPropertyName("BCustomName")]

diff --git a/source/Perun.Differ/DifferDotNet.cs b/source/Perun.Differ/DifferDotNet.cs
@@ -128,10 +128,15 @@ private static string GetCustomPropertyName<T>(Type type, T left, T right, Prope
             if (attr is null)
             {
                 return null;
+            }
+
+            if (attr.FromPropertyValue == false)
+            {
+                return attr.Name;
             }
 
             var segments = attr.Name.Split('.');
-            var nestedProp = prop;
+            var nestedProp = prop;
             var nestedType = type;
             object nestedLeft = left;
             object nestedRight = right;
@@ -152,12 +157,20 @@ private static string GetCustomPropertyName<T>(Type type, T left, T right, Prope
 
                 if (i < segments.Length - 1)
                 {
-                    nestedLeft = nestedProp.GetValue(nestedLeft);
-                    nestedRight = nestedProp.GetValue(nestedRight);
-                }
-            }
+                    nestedLeft = TryGetValue(nestedProp, nestedLeft);
+                    nestedRight = TryGetValue(nestedProp, nestedRight);
+                }
+            }
+
+            var customName = (TryGetValue(nestedProp, nestedRight) ?? TryGetValue(nestedProp, nestedLeft))?.ToString();
 
-            return (nestedProp.GetValue(nestedRight) ?? nestedProp.GetValue(nestedLeft))?.ToString();
+            return customName ?? attr.Name;
+        }
+
+        [CanBeNull]
+        private static object TryGetValue(PropertyInfo prop, object obj)
+        {
+            return obj is not null ? prop.GetValue(obj) : null;
         }
 
         private static bool HandleIterable<T>(