Asset importers, including any scripted importers that you write, must produce consistent, or deterministic results. A deterministic importer always produces the same output from the same input and set of dependencies, and always registers the same set of dependencies for a given environment.
The Asset Database has the following ways that you can check the consistency and determinism of the import results of the assets in your project:
-consistencyCheck command-line argument to open the Editor.
Manually reimporting an asset causes Unity to check whether a new import result matches the previous cached import results.
To start a manual reimport, select an asset and perform one of the following actions:
Unity then checks the resulting import for consistency. If it detects inconsistent results, Unity prints a warning in the Console windowA Unity Editor window that shows errors, warnings and other messages generated by Unity, or your own scripts. More info
See in Glossary with details about which importer caused the issue, such as:
Importer(<name of importer>) generated inconsistent result for asset(guid:<guid of the asset>) "<name of asset>"
When you reimport a root asset, Unity also reimports and performs the consistency check on its child assets.
To perform a check on all assets and importers in your project, open the Unity Editor with the -consistencyCheck command line argument. Unity then logs any inconsistencies found during startup to the console, and the Editor log file.
The -consistencyCheck argument has the following modes:
-consistencyCheckSourceMode local: Checks against the local result on disk in the Library folder.-consistencyCheckSourceMode cacheserver: Checks against a Unity Accelerator cache server.If you don’t pass the -consistencyCheckSourceMode argument, Unity performs a local check.
If you use -consistencyCheckSourceMode cacheserver, the consistency checker only checks asset imports that can be cached. For example, if you disable caching for a ScriptedImporter instance, then the consistency check for that import is also disabled. For more information, refer to AssetImporters.ScriptedImporterAttribute for details on how to disable caching for a scripted importer.
Important: If you use the cacheserver argument and Unity AcceleratorThe Unity Accelerator is an external tool that provides an asset cache that keeps copies of a team’s imported assets. The goal of the Accelerator is to speed up teamwork and reduce iteration time by coordinating asset sharing so that you don’t need to reimport portions of your project. More info
See in Glossary isn’t available, or hasn’t been set up, then the consistency checker prints out warnings in the Editor log that the cache server is unavailable. Additionally, if you use Unity Accelerator as the source, Unity disables uploads to the cache server to prevent uploading the result you’re about to check.
When Unity detects importer inconsistencies, you can find more information about the issue in the Editor log. This includes information such as:
To open the log:
The Editor log displays inconsistencies in the following format:
ConsistencyChecker - guid: <asset_guid>, dependenciesHash.value: <dep_hash_a>, importResultID: <result_id_a>, producedFiles[0].extension: , producedFiles[0].contentHash: <content_hash_a>
ConsistencyChecker - guid: <asset_guid>, dependenciesHash.value: <dep_hash_a>, importResultID: <result_id_b>, producedFiles[0].extension: , producedFiles[0].contentHash: <content_hash_b>
ConsistencyChecker - guid: <asset_guid>, dependenciesHash.value: <dep_hash_a>, importResultID: <result_id_b>, producedFiles[0].extension: , producedFiles[0].contentHash: <content_hash_b>
Importer(<importer_name>) generated inconsistent result for asset(<asset_guid>) <asset_path>
In the following example, two cached results share the same dependenciesHash value but have different importResultID values and different content hashes. This means the importer produced different output from the same input:
ConsistencyChecker - guid: a1945cd7aab67441ba89015f97494624, dependenciesHash.value: fb8cfb407bba82d4daded6031688ba9b, artifactid: 07078a054d3f597b4c2cc47e8e4c0bde, producedFiles[0].extension: , producedFiles[0].contentHash: 8490a5ed35a4361d679e6055a386969e
ConsistencyChecker - guid: a1945cd7aab67441ba89015f97494624, dependenciesHash.value: fb8cfb407bba82d4daded6031688ba9b, artifactid: 07078a054d3f597b4c2cc47e8e4c0bde, producedFiles[1].extension: .info, producedFiles[1].contentHash: 4bd9140e19d2e44782f1131172e514ba
ConsistencyChecker - guid: a1945cd7aab67441ba89015f97494624, dependenciesHash.value: fb8cfb407bba82d4daded6031688ba9b, artifactid: 646d6432767729ea7d288c636183de97, producedFiles[0].extension: , producedFiles[0].contentHash: 5ca760170f85012ce16aa8c22e8d9ea1
ConsistencyChecker - guid: a1945cd7aab67441ba89015f97494624, dependenciesHash.value: fb8cfb407bba82d4daded6031688ba9b, artifactid: 646d6432767729ea7d288c636183de97, producedFiles[1].extension: .info, producedFiles[1].contentHash: 4bd9140e19d2e44782f1131172e514ba
Importer(ScriptedImporter:Assembly-CSharp::RandomImporter) generated inconsistent result for asset(guid:a1945cd7aab67441ba89015f97494624) "Assets/first.rand"
A producedFile is in a binary format. You can use the binary2text tool to examine the contents of the Library folder to find out exactly what the importer generated. The binary2text tool is located in the Data/Tools folder in your Unity Editor installation. On macOS, this tool is located at Unity.app/Contents/Helpers/.
You can then open the converted inconsistent results in a diff tool to analyze which part of the import operation was non-deterministic.
For more information on the binary2text tool, refer to Analyze built assets.