What causes "hot update assembly name cann't be empty" in egametang/ET?

Open HybridCLRSettings (Project Settings > HybridCLR or the settings asset) and remove any empty or blank entries from the hot update assemblies list.

egametang/ET · error · BuildFailedException

hot update assembly name cann't be empty

Error message

hot update assembly name cann't be empty

What it means

Thrown by FilterHotFixAssemblies.OnFilterBuildAssemblies when iterating over the configured hot-update assembly names and encountering one that is null, empty, or whitespace. This runs during the build's assembly-filtering phase to strip hot-update DLLs from the main build. An empty entry in the list is treated as a configuration error rather than silently skipped.

Source

Thrown at Packages/cn.etetet.hybridclr/Scripts/Editor/Share/BuildProcessors/FilterHotFixAssemblies.cs:36

    {
        public int callbackOrder => 0;

        public string[] OnFilterAssemblies(BuildOptions buildOptions, string[] assemblies)
        {
            if (!SettingsUtil.Enable)
            {
                Debug.Log($"[FilterHotFixAssemblies] disabled");
                return assemblies;
            }
            List<string> allHotUpdateDllNames = SettingsUtil.HotUpdateAssemblyNamesExcludePreserved;

            // 检查是否重复填写
            var hotUpdateDllSet = new HashSet<string>();
            foreach(var hotUpdateDll in allHotUpdateDllNames)
            {
                if (string.IsNullOrWhiteSpace(hotUpdateDll))
                {
                    throw new BuildFailedException($"hot update assembly name cann't be empty");
                }
                if (!hotUpdateDllSet.Add(hotUpdateDll))
                {
                    throw new BuildFailedException($"hot update assembly:{hotUpdateDll} is duplicated");
                }
            }

            var assResolver = MetaUtil.CreateHotUpdateAssemblyResolver(EditorUserBuildSettings.activeBuildTarget, allHotUpdateDllNames);
            // 检查是否填写了正确的dll名称
            foreach (var hotUpdateDllName in allHotUpdateDllNames)
            {
                if (assemblies.Select(Path.GetFileNameWithoutExtension).All(ass => ass != hotUpdateDllName) 
                    && string.IsNullOrEmpty(assResolver.ResolveAssembly(hotUpdateDllName, false)))
                {
                    throw new BuildFailedException($"hot update assembly:{hotUpdateDllName} doesn't exist");
                }
            }

View on GitHub (pinned to 5cab01f7a8)

Solutions

Open HybridCLRSettings (Project Settings > HybridCLR or the settings asset) and remove any empty or blank entries from the hot update assemblies list.
If managing settings programmatically, filter out null/empty strings before assigning the array.
Inspect the serialized HybridCLRSettings asset in a text editor to find stray empty elements.
Re-enter the hot update assembly names cleanly, ensuring each is a valid assembly name without whitespace.

Example fix

// before — settings contains: ["HotUpdate", "", "GameLogic"]
// FilterHotFixAssemblies throws on the empty entry

// fix — clean the list in HybridCLRSettings:
// hotUpdateAssemblies: ["HotUpdate", "GameLogic"]  (remove the empty string)

// programmatic guard before build:
var names = SettingsUtil.HybridCLRSettings.hotUpdateAssemblies
    .Where(n => !string.IsNullOrWhiteSpace(n))
    .ToArray();
SettingsUtil.HybridCLRSettings.hotUpdateAssemblies = names;

Defensive patterns

Strategy: validation

Validate before calling

var names = SettingsUtil.HybridCLRSettings.hotUpdateAssemblies;
if (names != null)
{
    foreach (var name in names)
    {
        if (string.IsNullOrWhiteSpace(name))
        {
            Debug.LogError("An empty or null entry exists in HybridCLRSettings.hotUpdateAssemblies. Remove it before building.");
        }
    }
}

Type guard

static bool HasNoEmptyEntries(string[] names)
{
    return names == null || names.All(n => !string.IsNullOrWhiteSpace(n));
}

Try / catch

try
{
    BuildPipeline.BuildPlayer(scenes, outputPath, buildTarget, buildOptions);
}
catch (BuildFailedException ex) when (ex.Message.Contains("cann't be empty"))
{
    Debug.LogError("A hot-update assembly name is empty. Open HybridCLRSettings and remove blank entries.");
}

Prevention

When editing the hotUpdateAssemblies list in the inspector, delete empty array elements rather than clearing them.
Inspect the serialized HybridCLRSettings asset file for stray empty strings.
Programmatically filter out null/empty entries before assigning the settings array.
Add a pre-build validation step that checks for empty or invalid assembly names.

When it happens

Trigger: OnFilterBuildAssemblies iterates SettingsUtil.HotUpdateAssemblyNamesExcludePreserved (which combines hotUpdateAssemblies and hotUpdateAssemblyDefinitions from HybridCLRSettings). If any entry is null or whitespace, the BuildFailedException is thrown during build preprocessing.

Common situations: A stray empty string or null in the HybridCLRSettings hotUpdateAssemblies array (e.g. left by the Unity inspector when adding then clearing an element); a serialized settings asset with a trailing empty entry; programmatic settings modification that inserted null; copy-paste errors leaving blank lines in the list.

Related errors

AI-assisted analysis of egametang/ET@5cab01f7a8 (2026-08-13). Data as JSON: /api/errors/266f440806adc483. Report an issue: GitHub.