Make string indexer throw on unknown key, remove GetChild

xPaw · xPaw · commit 7be27b93cde9 · 2026-04-03T10:39:56.000+03:00
diff --git a/ValveKeyValue/ValveKeyValue.Test/ConversionCoverageTestCase.cs b/ValveKeyValue/ValveKeyValue.Test/ConversionCoverageTestCase.cs
@@ -251,7 +251,6 @@ public void DictBackedCollectionSetNullRemovesKey()
             data["key1"] = null;
 
             Assert.That(data.ContainsKey("key1"), Is.False);
-            Assert.That(data["key1"], Is.Null);
             Assert.That(data.Count, Is.EqualTo(1));
             Assert.That((int)data["key2"], Is.EqualTo(42));
         }
diff --git a/ValveKeyValue/ValveKeyValue.Test/EdgeCaseTestCase.cs b/ValveKeyValue/ValveKeyValue.Test/EdgeCaseTestCase.cs
@@ -88,7 +88,7 @@ public void IndexerSetNullRemovesChildFromListCollection()
 
             obj["a"] = null;
 
-            Assert.That(obj["a"], Is.Null);
+            Assert.That(obj.ContainsKey("a"), Is.False);
             Assert.That(obj.Count, Is.EqualTo(1));
             Assert.That((string)obj["b"], Is.EqualTo("2"));
         }
@@ -186,22 +186,22 @@ public void IntegerIndexerOnScalarThrowsNotSupportedException()
 
         #endregion
 
-        #region GetChild on scalar returns null
+        #region TryGetValue on scalar returns false
 
         [Test]
-        public void GetChildOnScalarReturnsNull()
+        public void TryGetValueOnScalarReturnsFalse()
         {
             var obj = new KVObject("hello");
 
-            Assert.That(obj.GetChild("x"), Is.Null);
+            Assert.That(obj.TryGetValue("x", out _), Is.False);
         }
 
         [Test]
-        public void GetChildOnNullValuedObjectReturnsNull()
+        public void TryGetValueOnNullValuedObjectReturnsFalse()
         {
             var obj = KVObject.Null();
 
-            Assert.That(obj.GetChild("x"), Is.Null);
+            Assert.That(obj.TryGetValue("x", out _), Is.False);
         }
 
         #endregion
@@ -484,16 +484,13 @@ public void DuplicateKeysPreservedInListCollection()
         }
 
         [Test]
-        public void GetChildReturnsFistForDuplicateKeysInListCollection()
+        public void IndexerReturnsFirstForDuplicateKeysInListCollection()
         {
             var obj = KVObject.ListCollection();
             obj.Add("key", "first");
             obj.Add("key", "second");
 
-            var child = obj.GetChild("key");
-
-            Assert.That(child, Is.Not.Null);
-            Assert.That((string)child, Is.EqualTo("first"));
+            Assert.That((string)obj["key"], Is.EqualTo("first"));
         }
 
         [Test]
@@ -640,11 +637,13 @@ public void DictAndListCollectionsHaveConsistentBehavior()
 
             Assert.Multiple(() =>
             {
-                // GetChild
-                Assert.That((int)dict.GetChild("a"), Is.EqualTo(1));
-                Assert.That((int)list.GetChild("a"), Is.EqualTo(1));
-                Assert.That(dict.GetChild("missing"), Is.Null);
-                Assert.That(list.GetChild("missing"), Is.Null);
+                // TryGetValue
+                Assert.That(dict.TryGetValue("a", out var dictA), Is.True);
+                Assert.That((int)dictA, Is.EqualTo(1));
+                Assert.That(list.TryGetValue("a", out var listA), Is.True);
+                Assert.That((int)listA, Is.EqualTo(1));
+                Assert.That(dict.TryGetValue("missing", out _), Is.False);
+                Assert.That(list.TryGetValue("missing", out _), Is.False);
 
                 // ContainsKey
                 Assert.That(dict.ContainsKey("a"), Is.True);
diff --git a/ValveKeyValue/ValveKeyValue.Test/KVBasicObjectIndexerTestCase.cs b/ValveKeyValue/ValveKeyValue.Test/KVBasicObjectIndexerTestCase.cs
@@ -3,9 +3,9 @@ namespace ValveKeyValue.Test
     class KVBasicObjectIndexerTestCase
     {
         [Test]
-        public void IndexerOnValueNodeReturnsNull()
+        public void IndexerOnValueNodeThrows()
         {
-            Assert.That(data["baz"], Is.Null);
+            Assert.That(() => data["baz"], Throws.TypeOf<KeyNotFoundException>());
         }
 
         KVObject data;
diff --git a/ValveKeyValue/ValveKeyValue.Test/KVObjectApiTestCase.cs b/ValveKeyValue/ValveKeyValue.Test/KVObjectApiTestCase.cs
@@ -23,11 +23,11 @@ public void IndexerReturnsKVObjectForExistingKey()
         }
 
         [Test]
-        public void IndexerReturnsNullForMissingKey()
+        public void IndexerThrowsForMissingKey()
         {
             var obj = KVObject.ListCollection();
             obj.Add("key", "value");
-            Assert.That(obj["missing"], Is.Null);
+            Assert.That(() => obj["missing"], Throws.TypeOf<KeyNotFoundException>());
         }
 
         [Test]
@@ -327,7 +327,7 @@ public void RemoveChildFromCollection()
 
             Assert.That(removed, Is.True);
             Assert.That(obj.Count, Is.EqualTo(1));
-            Assert.That(obj["a"], Is.Null);
+            Assert.That(obj.ContainsKey("a"), Is.False);
         }
 
         [Test]
@@ -478,7 +478,7 @@ public void ListCollectionAllowsDuplicateKeys()
             });
 
             Assert.That(obj.Count, Is.EqualTo(2));
-            // GetChild returns first match
+            // Indexer returns first match
             Assert.That((string)obj["key"], Is.EqualTo("first"));
         }
 
diff --git a/ValveKeyValue/ValveKeyValue.Test/KVObjectIndexerTestCase.cs b/ValveKeyValue/ValveKeyValue.Test/KVObjectIndexerTestCase.cs
@@ -5,13 +5,18 @@ class KVObjectIndexerTestCase
         [TestCase("foo", ExpectedResult = "bar")]
         [TestCase("bar", ExpectedResult = "baz")]
         [TestCase("baz", ExpectedResult = "-")]
-        [TestCase("foobar", ExpectedResult = null)]
         public string IndexerReturnsChildValue(string key) => (string)data[key];
 
         [Test]
-        public void IndexerOnValueNodeReturnsNull()
+        public void IndexerThrowsForMissingKey()
         {
-            Assert.That(data["foo"]["bar"], Is.Null);
+            Assert.That(() => data["foobar"], Throws.TypeOf<KeyNotFoundException>());
+        }
+
+        [Test]
+        public void IndexerOnValueNodeThrows()
+        {
+            Assert.That(() => data["foo"]["bar"], Throws.TypeOf<KeyNotFoundException>());
         }
 
         KVObject data;
diff --git a/ValveKeyValue/ValveKeyValue.Test/KVObjectTestCase.cs b/ValveKeyValue/ValveKeyValue.Test/KVObjectTestCase.cs
@@ -7,7 +7,7 @@ public void IndexerSetterWorks()
         {
             var obj = KVObject.ListCollection();
 
-            Assert.That(obj["this_is_set_in_test"], Is.Null);
+            Assert.That(obj.ContainsKey("this_is_set_in_test"), Is.False);
             obj["this_is_set_in_test"] = "some cool data";
             Assert.That((string)obj["this_is_set_in_test"], Is.EqualTo("some cool data"));
         }
@@ -17,7 +17,7 @@ public void AddCallWorks()
         {
             var obj = KVObject.ListCollection();
 
-            Assert.That(obj["this_is_set_in_test"], Is.Null);
+            Assert.That(obj.ContainsKey("this_is_set_in_test"), Is.False);
             obj.Add("this_is_set_in_test", "some cool data");
             Assert.That((string)obj["this_is_set_in_test"], Is.EqualTo("some cool data"));
         }
diff --git a/ValveKeyValue/ValveKeyValue.Test/RoundTripTestCase.cs b/ValveKeyValue/ValveKeyValue.Test/RoundTripTestCase.cs
@@ -221,7 +221,7 @@ public void RemovingChildrenThenSerializingKV1()
             {
                 Assert.That(result.Count, Is.EqualTo(2));
                 Assert.That((string)result["keep"], Is.EqualTo("yes"));
-                Assert.That(result["remove"], Is.Null);
+                Assert.That(result.ContainsKey("remove"), Is.False);
                 Assert.That((string)result["also_keep"], Is.EqualTo("yes"));
             });
         }
@@ -243,7 +243,7 @@ public void RemovingChildrenThenSerializingKV3()
             {
                 Assert.That(result.Count, Is.EqualTo(2));
                 Assert.That((string)result["keep"], Is.EqualTo("yes"));
-                Assert.That(result["remove"], Is.Null);
+                Assert.That(result.ContainsKey("remove"), Is.False);
                 Assert.That((string)result["also_keep"], Is.EqualTo("yes"));
             });
         }
diff --git a/ValveKeyValue/ValveKeyValue.Test/Test Data/apisurface.txt b/ValveKeyValue/ValveKeyValue.Test/Test Data/apisurface.txt
@@ -55,7 +55,6 @@ public class ValveKeyValue.KVDocument
     public string get_Name();
     public System.Collections.Generic.IEnumerable`1[[ValveKeyValue.KVObject]] get_Values();
     public ValveKeyValue.KVValueType get_ValueType();
-    public ValveKeyValue.KVObject GetChild(string name);
     public System.Collections.Generic.IEnumerator`1[[System.Collections.Generic.KeyValuePair`2[[string, ValveKeyValue.KVObject]]]] GetEnumerator();
     public int GetHashCode();
     public Type GetType();
@@ -178,7 +177,6 @@ public class ValveKeyValue.KVObject
     public System.Collections.Generic.IEnumerable`1[[string]] get_Keys();
     public System.Collections.Generic.IEnumerable`1[[ValveKeyValue.KVObject]] get_Values();
     public ValveKeyValue.KVValueType get_ValueType();
-    public ValveKeyValue.KVObject GetChild(string name);
     public System.Collections.Generic.IEnumerator`1[[System.Collections.Generic.KeyValuePair`2[[string, ValveKeyValue.KVObject]]]] GetEnumerator();
     public int GetHashCode();
     public Type GetType();
diff --git a/ValveKeyValue/ValveKeyValue.Test/Text/ConditionalTestCase.cs b/ValveKeyValue/ValveKeyValue.Test/Text/ConditionalTestCase.cs
@@ -47,7 +47,7 @@ public void ReadsValueWhenConditionalWithAndOnlyMatchesOneSide()
             var conditions = new[] { "X360WIDE" };
             var data = ParseResource("Text.conditional.vdf", conditions);
 
-            Assert.That((string)data["ui type"], Is.Null);
+            Assert.That(data.ContainsKey("ui type"), Is.False);
         }
 
         [Test]
diff --git a/ValveKeyValue/ValveKeyValue.Test/Text/ConditionalsInMultipleObjects.cs b/ValveKeyValue/ValveKeyValue.Test/Text/ConditionalsInMultipleObjects.cs
@@ -8,9 +8,9 @@ public void ShouldCorrectlyDiscardMultipleConditionsAndEndObject()
             using var stream = TestDataHelper.OpenResource("Text.conditional_discard.vdf");
             var kv = KVSerializer.Create(KVSerializationFormat.KeyValues1Text).Deserialize(stream);
 
-            Assert.That(kv["One"]["Key1"], Is.Null);
-            Assert.That(kv["Two"]["Key2"], Is.Null);
-            Assert.That(kv["Three"]["Key3"], Is.Null);
+            Assert.That(kv["One"].ContainsKey("Key1"), Is.False);
+            Assert.That(kv["Two"].ContainsKey("Key2"), Is.False);
+            Assert.That(kv["Three"].ContainsKey("Key3"), Is.False);
         }
     }
 }
diff --git a/ValveKeyValue/ValveKeyValue.Test/Text/LegacyDepotDataSubsetTestCase.cs b/ValveKeyValue/ValveKeyValue.Test/Text/LegacyDepotDataSubsetTestCase.cs
@@ -43,15 +43,13 @@ public void HasItemWithValueCast(string key, string expectedValue)
         [TestCaseSource(nameof(GarbageItemsTestCaseData))]
         public void DoesNotHaveGarbageItems(string key)
         {
-            var value = data[key];
-            Assert.That(value, Is.Null);
+            Assert.That(data.ContainsKey(key), Is.False);
         }
 
         [TestCaseSource(nameof(GarbageItemsTestCaseData))]
         public void DoesNotHaveGarbageWithValueCast(string key)
         {
-            var value = data[key];
-            Assert.That((string)value, Is.Null);
+            Assert.That(data.TryGetValue(key, out _), Is.False);
         }
 
         static IEnumerable ItemsTestCaseData
diff --git a/ValveKeyValue/ValveKeyValue/KVObject.cs b/ValveKeyValue/ValveKeyValue/KVObject.cs
@@ -174,12 +174,21 @@ internal KVObject(KVValueType type, object refValue, KVFlag flag = KVFlag.None)
         #region Indexers
 
         /// <summary>
-        /// Gets or sets a child by key. Returns <c>null</c> if the key is not found.
+        /// Gets or sets a child by key.
         /// Setting a value creates or replaces the child with the given key.
         /// </summary>
+        /// <exception cref="KeyNotFoundException">The key was not found (getter only).</exception>
         public KVObject this[string key]
         {
-            get => GetChild(key);
+            get
+            {
+                if (!TryGetValue(key, out var child))
+                {
+                    throw new KeyNotFoundException($"The given key '{key}' was not present.");
+                }
+
+                return child;
+            }
             set
             {
                 ArgumentNullException.ThrowIfNull(key);
@@ -213,27 +222,22 @@ public KVObject this[int index]
         #region Navigation
 
         /// <summary>
-        /// Gets a child <see cref="KVObject"/> by key.
+        /// Tries to get a child <see cref="KVObject"/> by key.
         /// </summary>
-        public KVObject GetChild(string name)
+        public bool TryGetValue(string name, out KVObject child)
         {
             ArgumentNullException.ThrowIfNull(name);
 
-            return _ref switch
+            switch (_ref)
             {
-                Dictionary<string, KVObject> dict => dict.GetValueOrDefault(name),
-                List<KeyValuePair<string, KVObject>> list when ValueType == KVValueType.Collection => FindInList(list, name),
-                _ => null,
-            };
-        }
-
-        /// <summary>
-        /// Tries to get a child <see cref="KVObject"/> by key.
-        /// </summary>
-        public bool TryGetValue(string name, out KVObject child)
-        {
-            child = GetChild(name);
-            return child != null;
+                case Dictionary<string, KVObject> dict:
+                    return dict.TryGetValue(name, out child);
+                case List<KeyValuePair<string, KVObject>> list when ValueType == KVValueType.Collection:
+                    return TryFindInList(list, name, out child);
+                default:
+                    child = null;
+                    return false;
+            }
         }
 
         /// <summary>
@@ -246,7 +250,7 @@ public bool ContainsKey(string name)
             return _ref switch
             {
                 Dictionary<string, KVObject> dict => dict.ContainsKey(name),
-                List<KeyValuePair<string, KVObject>> list when ValueType == KVValueType.Collection => FindInList(list, name) != null,
+                List<KeyValuePair<string, KVObject>> list when ValueType == KVValueType.Collection => TryFindInList(list, name, out _),
                 _ => false,
             };
         }
@@ -584,17 +588,19 @@ private IEnumerable<KeyValuePair<string, KVObject>> EnumerateArray()
             }
         }
 
-        private static KVObject FindInList(List<KeyValuePair<string, KVObject>> list, string name)
+        private static bool TryFindInList(List<KeyValuePair<string, KVObject>> list, string name, out KVObject value)
         {
             foreach (var kvp in list)
             {
                 if (kvp.Key == name)
                 {
-                    return kvp.Value;
+                    value = kvp.Value;
+                    return true;
                 }
             }
 
-            return null;
+            value = null;
+            return false;
         }
 
         private string DebuggerDescription => ValueType switch

Original file line number	Diff line number	Diff line change
`@@ -251,7 +251,6 @@ public void DictBackedCollectionSetNullRemovesKey()`
`251`	`251`	`data["key1"] = null;`
`252`	`252`
`253`	`253`	`Assert.That(data.ContainsKey("key1"), Is.False);`
`254`		`- Assert.That(data["key1"], Is.Null);`
`255`	`254`	`Assert.That(data.Count, Is.EqualTo(1));`
`256`	`255`	`Assert.That((int)data["key2"], Is.EqualTo(42));`
`257`	`256`	`}`
Original file line number	Diff line number	Diff line change
`@@ -3,9 +3,9 @@ namespace ValveKeyValue.Test`
`3`	`3`	`class KVBasicObjectIndexerTestCase`
`4`	`4`	`{`
`5`	`5`	`[Test]`
`6`		`- public void IndexerOnValueNodeReturnsNull()`
	`6`	`+ public void IndexerOnValueNodeThrows()`
`7`	`7`	`{`
`8`		`- Assert.That(data["baz"], Is.Null);`
	`8`	`+ Assert.That(() => data["baz"], Throws.TypeOf<KeyNotFoundException>());`
`9`	`9`	`}`
`10`	`10`
`11`	`11`	`KVObject data;`
Original file line number	Diff line number	Diff line change
`@@ -23,11 +23,11 @@ public void IndexerReturnsKVObjectForExistingKey()`
`23`	`23`	`}`
`24`	`24`
`25`	`25`	`[Test]`
`26`		`- public void IndexerReturnsNullForMissingKey()`
	`26`	`+ public void IndexerThrowsForMissingKey()`
`27`	`27`	`{`
`28`	`28`	`var obj = KVObject.ListCollection();`
`29`	`29`	`obj.Add("key", "value");`
`30`		`- Assert.That(obj["missing"], Is.Null);`
	`30`	`+ Assert.That(() => obj["missing"], Throws.TypeOf<KeyNotFoundException>());`
`31`	`31`	`}`
`32`	`32`
`33`	`33`	`[Test]`
`@@ -327,7 +327,7 @@ public void RemoveChildFromCollection()`
`327`	`327`
`328`	`328`	`Assert.That(removed, Is.True);`
`329`	`329`	`Assert.That(obj.Count, Is.EqualTo(1));`
`330`		`- Assert.That(obj["a"], Is.Null);`
	`330`	`+ Assert.That(obj.ContainsKey("a"), Is.False);`
`331`	`331`	`}`
`332`	`332`
`333`	`333`	`[Test]`
`@@ -478,7 +478,7 @@ public void ListCollectionAllowsDuplicateKeys()`
`478`	`478`	`});`
`479`	`479`
`480`	`480`	`Assert.That(obj.Count, Is.EqualTo(2));`
`481`		`- // GetChild returns first match`
	`481`	`+ // Indexer returns first match`
`482`	`482`	`Assert.That((string)obj["key"], Is.EqualTo("first"));`
`483`	`483`	`}`
`484`	`484`
Original file line number	Diff line number	Diff line change
`@@ -7,7 +7,7 @@ public void IndexerSetterWorks()`
`7`	`7`	`{`
`8`	`8`	`var obj = KVObject.ListCollection();`
`9`	`9`
`10`		`- Assert.That(obj["this_is_set_in_test"], Is.Null);`
	`10`	`+ Assert.That(obj.ContainsKey("this_is_set_in_test"), Is.False);`
`11`	`11`	`obj["this_is_set_in_test"] = "some cool data";`
`12`	`12`	`Assert.That((string)obj["this_is_set_in_test"], Is.EqualTo("some cool data"));`
`13`	`13`	`}`
`@@ -17,7 +17,7 @@ public void AddCallWorks()`
`17`	`17`	`{`
`18`	`18`	`var obj = KVObject.ListCollection();`
`19`	`19`
`20`		`- Assert.That(obj["this_is_set_in_test"], Is.Null);`
	`20`	`+ Assert.That(obj.ContainsKey("this_is_set_in_test"), Is.False);`
`21`	`21`	`obj.Add("this_is_set_in_test", "some cool data");`
`22`	`22`	`Assert.That((string)obj["this_is_set_in_test"], Is.EqualTo("some cool data"));`
`23`	`23`	`}`
Original file line number	Diff line number	Diff line change
`@@ -221,7 +221,7 @@ public void RemovingChildrenThenSerializingKV1()`
`221`	`221`	`{`
`222`	`222`	`Assert.That(result.Count, Is.EqualTo(2));`
`223`	`223`	`Assert.That((string)result["keep"], Is.EqualTo("yes"));`
`224`		`- Assert.That(result["remove"], Is.Null);`
	`224`	`+ Assert.That(result.ContainsKey("remove"), Is.False);`
`225`	`225`	`Assert.That((string)result["also_keep"], Is.EqualTo("yes"));`
`226`	`226`	`});`
`227`	`227`	`}`
`@@ -243,7 +243,7 @@ public void RemovingChildrenThenSerializingKV3()`
`243`	`243`	`{`
`244`	`244`	`Assert.That(result.Count, Is.EqualTo(2));`
`245`	`245`	`Assert.That((string)result["keep"], Is.EqualTo("yes"));`
`246`		`- Assert.That(result["remove"], Is.Null);`
	`246`	`+ Assert.That(result.ContainsKey("remove"), Is.False);`
`247`	`247`	`Assert.That((string)result["also_keep"], Is.EqualTo("yes"));`
`248`	`248`	`});`
`249`	`249`	`}`
Original file line number	Diff line number	Diff line change
`@@ -47,7 +47,7 @@ public void ReadsValueWhenConditionalWithAndOnlyMatchesOneSide()`
`47`	`47`	`var conditions = new[] { "X360WIDE" };`
`48`	`48`	`var data = ParseResource("Text.conditional.vdf", conditions);`
`49`	`49`
`50`		`- Assert.That((string)data["ui type"], Is.Null);`
	`50`	`+ Assert.That(data.ContainsKey("ui type"), Is.False);`
`51`	`51`	`}`
`52`	`52`
`53`	`53`	`[Test]`
Original file line number	Diff line number	Diff line change
`@@ -8,9 +8,9 @@ public void ShouldCorrectlyDiscardMultipleConditionsAndEndObject()`
`8`	`8`	`using var stream = TestDataHelper.OpenResource("Text.conditional_discard.vdf");`
`9`	`9`	`var kv = KVSerializer.Create(KVSerializationFormat.KeyValues1Text).Deserialize(stream);`
`10`	`10`
`11`		`- Assert.That(kv["One"]["Key1"], Is.Null);`
`12`		`- Assert.That(kv["Two"]["Key2"], Is.Null);`
`13`		`- Assert.That(kv["Three"]["Key3"], Is.Null);`
	`11`	`+ Assert.That(kv["One"].ContainsKey("Key1"), Is.False);`
	`12`	`+ Assert.That(kv["Two"].ContainsKey("Key2"), Is.False);`
	`13`	`+ Assert.That(kv["Three"].ContainsKey("Key3"), Is.False);`
`14`	`14`	`}`
`15`	`15`	`}`
`16`	`16`	`}`