egametang/ET · error · Exception

btenv not found key

Error message

btenv not found key: {key} {typeof(T).FullName}

What it means

Thrown by BTEnv.GetCollection<T> when the requested key is absent from the env's internal dict. BTEnv is a typed blackboard shared across behavior-tree nodes; GetCollection retrieves an IEnumerable previously added via AddCollection. The exception surfaces both the missing key and the expected element type so you can tell which collection accessor failed.

Solutions

1. Verify the key string matches exactly between the AddCollection call and the GetCollection call (check spelling and casing).
2. Ensure the node that calls AddCollection runs before the node that calls GetCollection in the tree order.
3. Guard the read with env.ContainKey(key) before calling GetCollection, or use a default value.
4. If using pooled BTEnv, confirm the env was not cleared/recycled between write and read.

Example fix

// before
var targets = env.GetCollection<List<long>>("targets"); // throws [40] if never set

// after
if (env.ContainKey("targets"))
{
    var targets = env.GetCollection<List<long>>("targets");
}

if (!env.ContainKey("targets")) { /* return default or skip */ }
var targets = env.GetCollection<List<long>>("targets");

try { var targets = env.GetCollection<List<long>>("targets"); }
catch (Exception e) when (e.Message.Contains("btenv not found key")) { /* key absent */ }

When it happens

Trigger: Calling env.GetCollection<List<long>>("targets") (or any T:IEnumerable) when no AddCollection call ever wrote that key, or when the key was written under a different name/string literal.

Common situations: A BT node handler reads a collection that an upstream node was supposed to populate but the upstream branch never ran; a typo between the key used at AddCollection and at GetCollection; the tree was re-entered on a pooled BTEnv whose IPool.Clear wiped the dict.

Related errors

• 不能把 转换为
• condition root child count error
• unknown condition compare op
• add cancel token is null
• Arg_ArrayPlusOffTooSmall

AI-assisted analysis of egametang/ET@5cab01f7a8 (2026-08-13). Data as JSON: /api/errors/f2380f70e7223790. Report an issue: GitHub.

Appendix: source

Thrown at Packages/cn.etetet.behaviortree/Scripts/Model/Share/BTEnv.cs:87

            env.RunPath.AddRange(this.RunPath);
            env.EntityId = this.EntityId;
            env.TreeId = this.TreeId;
#endif
            return env;
        }

        public void SetTreeId(long treeId)
        {
#if UNITY_EDITOR
            this.TreeId = treeId;
#endif
        }
        
        public T GetCollection<T>(string key) where T: IEnumerable
        {
            if (!this.dict.TryGetValue(key, out object value))
            {
                throw new Exception($"btenv not found key: {key} {typeof(T).FullName}");
            }
            
            return (T)value;
        }
        
        
        public bool TryGetStruct<T>(string key, out T t) where T: struct
        {
            t = default;
            if (key == null)
            {
                return false;
            }
            
            if (!this.dict.TryGetValue(key, out object value))
            {
                return false;
            }

View on GitHub (pinned to 5cab01f7a8)