FIX: Fixed Input Actions code generation overwriting user files when the names happened to match. (#2159)

Author: K-Tone

Packages/com.unity.inputsystem/CHANGELOG.md

@@ -16,6 +16,7 @@ however, it has to be formatted properly to pass verification tests.
 - Fixed issue where user was not prompted to save changes when loading a second input actions asset into an already opened editor. [ISXB-1343](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1343)
 - Fixed the on hover behaviour of the two plus buttons in the Input Actions Editor window [ISXB-1327](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1327)
 - Fixed an issue on macOS which didn't detect up-left DPAD presses for Xbox controllers. [ISXB-810](https://issuetracker.unity3d.com/issues/macos-d-pad-upper-left-corner-is-not-logged-with-the-xbox-controller)
+- Fixed Input Actions code generation overwriting user files when the names happened to match. [ISXB-1257](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-1257)
 - Fixed an issue when providing JoinPlayer with a specific split screen index. [ISXB-897](https://issuetracker.unity3d.com/product/unity/issues/guid/ISXB-897)
 
 ## [1.14.0] - 2025-03-20

Packages/com.unity.inputsystem/InputSystem/Editor/AssetImporter/InputActionImporter.cs

@@ -247,6 +247,18 @@ private static void GenerateWrapperCode(AssetImportContext ctx, InputActionAsset
             if (!Directory.Exists(dir))
                 Directory.CreateDirectory(dir);
 
+            // Check for the case where the target file already exists.
+            // If it does, we don't want to overwrite it unless it's been generated by us before.
+            if (File.Exists(wrapperFilePath))
+            {
+                var text = File.ReadAllText(wrapperFilePath);
+                var autoGeneratedMarker = "This code was auto-generated by com.unity.inputsystem";
+                if (!text.Contains(autoGeneratedMarker))
+                {
+                    throw new Exception($"The target file for Input Actions code generation already exists: {wrapperFilePath}. Since it doesn't look to contain Input generated code that we can safely overwrite, we stopped to prevent any data loss. Consider renaming. ");
+                }
+            }
+
             var options = new InputActionCodeGenerator.Options
             {
                 sourceAssetPath = ctx.assetPath,