To improve usability and performance, Unity might change the way classes, functions and properties (the API) work. Occasionally, these improvements might introduce breaking changes when moving from one major Unity version to another.
To minimize the impact of breaking changes, the API updater identifies and updates obsolete code in your scripts and assemblies.
The API updater consists of the ScriptUpdater and the AssemblyUpdater, which are responsible for updating source code (scripts) and assemblies (dll files) respectively.
Note: The API Updater can only fix certain errors and warnings in the API. These are indicated as UnityUpgradable in the console message. You must manually resolve other errors or warnings that the API Updater cannot handle.
When a script compilation is triggered, the API updater runs automatically. For example, this occurs when you:
The API updater offers to update any obsolete code that it detects. If you accept, it rewrites any obsolete code with the recommended updated version of the API.
For example, the API updater would convert the following obsolete statement from:
light.color = Color.red;
to:
GetComponent<Light>().color = Color.red;
The steps below describe the workflow of the API updater when Unity triggers a script compilation:
The updater can run multiple times if scripts with obsolete code fall into different compilation passes, for example, editor scripts. When the API Updater successfully finishes, the console displays the message: Finished updating scripts / assemblies.
If you don’t allow the API updater to update your scripts, the console displays any script errors or warnings. Errors or warnings which the API updater could resolve display (UnityUpgradable) in the message.
If your script has other errors which prevent the API updater from running successfully, the Console displays a message to inform you of this. You must resolve those errors before the API Updater can complete the updates.
When running Unity in batch mode from the command line, use the -accept-apiupdate
option to run the API updater. For more information, see Command Line Arguments.
The API updater logs changes it makes to any assemblies to the Editor log. To control how much information is logged, set the UNITY_APIUPDATER_LOG_THRESHOLD environment variable to the desired log threshold and start Unity. For example:
Windows:
c:> set UNITY_APIUPDATER_LOG_THRESHOLD=Debug
c:> \path\to\unity\Unity.exe
On Linux:
$ export UNITY_APIUPDATER_LOG_THRESHOLD=Debug
$ /path/to/unity/Unity
在 Mac 上:
$ export UNITY_APIUPDATER_LOG_THRESHOLD=Debug
$ /path/to/unity/Unity
Note: You can also use version control to see changes the API updater makes to a project’s scripts.
When AssemblyUpdater has finished, the Editor.log displays the changes. For example:
[AssemblyUpdater] Property access to 'UnityEngine.Rigidbody
UnityEngine.GameObject::get_rigidbody()' in 'System.Void
Test.ClassReferencingObsoleteUnityAPIThroughEditorAssembly::Run()' replaced with 'T
UnityEngine.GameObject::GetComponent<UnityEngine.Rigidbody>()'.
The table below describes the values for the UNITY_APIUPDATER_LOG_THRESHOLD
environment variable:
Log threshold | 描述 |
---|---|
Error (default value) | The API updater only logs Error messages. Error messages are logged when the API updater fails to apply a specific update, which requires you to take corrective action (usually requesting the original assembly author to provide an updated version of the assembly). |
Warning | The API updater logs Warning and Error messages. Warning messages are logged when the API updater applies a change that the user might need to review. |
Info | The API updater logs Informational, Warning and Error messages. Info messages include updates applied by the AssemblyUpdater. |
Debug | The API updater logs all messages. This is useful for troubleshooting, for example if you have issues with the API updater that you want to report to Unity. |
The API updater couldn’t update all obsolete code. This can occur if the updater can’t save its changes, for example if the user has read-only permissions on the script.
Check the previous lines in the console to see any problems that occurred during the update process.
2018–07–31 页面已修订
Unity 2017.2 中添加了“accept-apiupdate”命令行选项
在 Unity 2018.3 版本中改进了 AssemblyUpdater 日志记录 NewIn20183