FIX: Fix Precompiled Layouts for types with no namespace (ISXB-552) (#1702)

* Fix GenerateCodeForDeviceLayout when the layout does not have a namespace

* move CHANGELOG entry after merge with develop

* run code formatter

---------

Co-authored-by: James McGill <jamesmcgill@users.noreply.github.com>
Co-authored-by: James McGill <james.mcgill@unity3d.com>

Author: mtschoen-unity

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -22,6 +22,7 @@ however, it has to be formatted properly to pass verification tests.
 - Fixed Tracked Pose Driver to use `Transform.SetLocalPositionAndRotation` when available to improve performance. Based on the user contribution from [DevDunk](https://forum.unity.com/members/devdunk.4432119/) in a [forum post](https://forum.unity.com/threads/more-performant-tracked-pose-driver-solution-included.1462691).
 - Fixed the `Clone` methods of `InputAction` and `InputActionMap` so it copies the Initial State Check flag (`InputAction.wantsInitialStateCheck`) of input actions.
 - Fixed the "Release tests throws exception in InputSystem" bug ([case ISXB-581](https://issuetracker.unity3d.com/issues/release-tests-fail-when-input-system-package-is-installed)).
+- Fixed issues with generating Precompiled Layouts for devices which are not defined in a namespace
 
 ## [1.6.3] - 2023-07-11
 

Packages/com.unity.inputsystem/InputSystem/Editor/InputLayoutCodeGenerator.cs

@@ -110,11 +110,17 @@ public static unsafe string GenerateCodeForDeviceLayout(string layoutName, strin
             writer.WriteLine("// that we don't end up using.");
             writer.WriteLine("#pragma warning disable CS0219");
             writer.WriteLine("");
-            if (@namespace != "")
+            if (!string.IsNullOrEmpty(@namespace))
+            {
                 writer.WriteLine("namespace " + @namespace);
-            writer.BeginBlock();
+                writer.BeginBlock();
+            }
+
+            if (string.IsNullOrEmpty(baseTypeNamespace))
+                writer.WriteLine($"{visibility} partial class {namePrefix}{baseTypeName} : {baseTypeName}");
+            else
+                writer.WriteLine($"{visibility} partial class {namePrefix}{baseTypeName} : {baseTypeNamespace}.{baseTypeName}");
 
-            writer.WriteLine($"{visibility} partial class {namePrefix}{baseTypeName} : {baseTypeNamespace}.{baseTypeName}");
             writer.BeginBlock();
 
             // "Metadata". ATM this is simply a flat, semicolon-separated list of names for layouts and processors that
@@ -304,7 +310,9 @@ public static unsafe string GenerateCodeForDeviceLayout(string layoutName, strin
             }
 
             writer.EndBlock();
-            writer.EndBlock();
+
+            if (!string.IsNullOrEmpty(@namespace))
+                writer.EndBlock();
 
             if (defines != null)
                 writer.WriteLine($"#endif // {defines}");