Documentation

Unity Engine

User Manual

Script Reference

Unity Engine

Check the consistency of the import process

Verify that the import process produces consistent results for the same asset.
Read time 4 minutesLast updated 3 days ago
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:

Manually reimport assets

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:
  • Right-click on the asset and select Reimport from the context menu.
  • Go to Assets > Reimport.
Unity then checks the resulting import for consistency. If it detects inconsistent results, Unity prints a warning in the Console window 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.

Run consistency checks with the command-line

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 Accelerator 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.

Editor log output

When Unity detects importer inconsistencies, you can find more information about the issue in the Editor log. This includes information such as:
  • Which asset caused the failed consistency check and its GUID.
  • The content hash for the asset import result.
  • A comparison of the previous revision of the asset.
To open the log:
  1. Open the Console window (Window > General > Console).
  2. Select the More menu (⋮) and select Open Editor 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>

Inconsistent result log example

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: 8490a5ed35a4361d679e6055a386969eConsistencyChecker - guid: a1945cd7aab67441ba89015f97494624, dependenciesHash.value: fb8cfb407bba82d4daded6031688ba9b, artifactid: 07078a054d3f597b4c2cc47e8e4c0bde, producedFiles[1].extension: .info, producedFiles[1].contentHash: 4bd9140e19d2e44782f1131172e514baConsistencyChecker - guid: a1945cd7aab67441ba89015f97494624, dependenciesHash.value: fb8cfb407bba82d4daded6031688ba9b, artifactid: 646d6432767729ea7d288c636183de97, producedFiles[0].extension: , producedFiles[0].contentHash: 5ca760170f85012ce16aa8c22e8d9ea1ConsistencyChecker - guid: a1945cd7aab67441ba89015f97494624, dependenciesHash.value: fb8cfb407bba82d4daded6031688ba9b, artifactid: 646d6432767729ea7d288c636183de97, producedFiles[1].extension: .info, producedFiles[1].contentHash: 4bd9140e19d2e44782f1131172e514baImporter(ScriptedImporter:Assembly-CSharp::RandomImporter) generated inconsistent result for asset(guid:a1945cd7aab67441ba89015f97494624) "Assets/first.rand"

Convert produced files

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.

Additional resources