Fix exception thrown by disctionary inside formatting options

src/Protocol/Models/FormattingOptions.cs

@@ -15,7 +15,7 @@ public class FormattingOptions : Dictionary<string, BooleanNumberString>
         [JsonIgnore]
         public long TabSize
         {
-            get => this["tabSize"].IsLong ? this["tabSize"].Long : -1;
+            get => TryGetValue("tabSize", out var tabSize) && tabSize.IsLong ? tabSize.Long : -1;
             set => this["tabSize"] = value;
         }
 
@@ -25,7 +25,7 @@ public long TabSize
         [JsonIgnore]
         public bool InsertSpaces
         {
-            get => this["insertSpaces"].IsBool ? this["insertSpaces"].Bool : false;
+            get => TryGetValue("insertSpaces", out var insertSpaces) && insertSpaces.IsBool && insertSpaces.Bool;
             set => this["insertSpaces"] = value;
         }
 
@@ -37,7 +37,7 @@ public bool InsertSpaces
         [JsonIgnore]
         public bool TrimTrailingWhitespace
         {
-            get => this["trimTrailingWhitespace"].IsBool ? this["trimTrailingWhitespace"].Bool : false;
+            get => TryGetValue("trimTrailingWhitespace", out var trimTrailingWhitespace) && trimTrailingWhitespace.IsBool && trimTrailingWhitespace.Bool;
             set => this["trimTrailingWhitespace"] = value;
         }
 
@@ -49,7 +49,7 @@ public bool TrimTrailingWhitespace
         [JsonIgnore]
         public bool InsertFinalNewline
         {
-            get => this["insertFinalNewline"].IsBool ? this["insertFinalNewline"].Bool : false;
+            get => TryGetValue("insertFinalNewline", out var insertFinalNewline) && insertFinalNewline.IsBool && insertFinalNewline.Bool;
             set => this["insertFinalNewline"] = value;
         }
 
@@ -61,7 +61,7 @@ public bool InsertFinalNewline
         [JsonIgnore]
         public bool TrimFinalNewlines
         {
-            get => this["trimFinalNewlines"].IsBool ? this["trimFinalNewlines"].Bool : false;
+            get => TryGetValue("trimFinalNewlines", out var trimFinalNewlines) && trimFinalNewlines.IsBool && trimFinalNewlines.Bool;
             set => this["trimFinalNewlines"] = value;
         }
     }

test/Lsp.Tests/Models/FormattingOptionsTests.cs

@@ -1,4 +1,5 @@
 using FluentAssertions;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
 using OmniSharp.Extensions.LanguageServer.Protocol.Client.Capabilities;
 using OmniSharp.Extensions.LanguageServer.Protocol.Models;
 using OmniSharp.Extensions.LanguageServer.Protocol.Serialization;
@@ -24,5 +25,27 @@ public void SimpleTest(string expected)
             var deresult = new Serializer(ClientVersion.Lsp3).DeserializeObject<FormattingOptions>(expected);
             deresult.Should().BeEquivalentTo(model);
         }
+
+        [Fact]
+        public void Should_Not_Require_A_Value_To_Be_Defined()
+        {
+            var model = new FormattingOptions();
+            model.InsertSpaces.Should().BeFalse();
+            model.TabSize.Should().Be(-1L);
+            model.InsertFinalNewline.Should().BeFalse();
+            model.TrimFinalNewlines.Should().BeFalse();
+            model.TrimTrailingWhitespace.Should().BeFalse();
+        }
+
+        [Fact]
+        public void Should_Allow_Values_To_Be_Set()
+        {
+            var model = new FormattingOptions();
+            model.InsertSpaces = true;
+            model.TabSize = 4;
+            model.InsertFinalNewline = true;
+            model.TrimFinalNewlines = true;
+            model.TrimTrailingWhitespace = true;
+        }
     }
 }