EllanJiang/GameFramework · error · GameFrameworkException

First is invalid.

Error message

First is invalid.

What it means

GameFrameworkLinkedList<T>.RemoveFirst tries to remove the first node of the underlying LinkedList and release it back to the node pool. The list's First node is null (the list is empty), which the wrapper treats as an invalid state and throws instead of letting the raw list silently do nothing or throw its own error.

Solutions

1. Check Count > 0 (or First != null) before calling RemoveFirst
2. Use TryGetFirst/First value access guards or restructure the loop to use a while (list.Count > 0) condition
3. Catch GameFrameworkException and treat empty list as a no-op if acceptable

Example fix

// before
while (true) { list.RemoveFirst(); }
// after
while (list.Count > 0) { list.RemoveFirst(); }

if (list.Count > 0) { list.RemoveFirst(); }

static bool CanRemoveFirst<T>(GameFrameworkLinkedList<T> list) => list != null && list.Count > 0;

try { list.RemoveFirst(); }
catch (GameFrameworkException) { /* list already empty; treat as no-op */ }

When it happens

Trigger: Calling RemoveFirst() on an empty GameFrameworkLinkedList — e.g. draining a queue with RemoveFirst without checking Count, or after all nodes were already removed.

Common situations: Consumer loops popping from a pooled linked list until empty; double-drain after Clear; logic bugs where items were consumed elsewhere before RemoveFirst is called.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Last is invalid.
• Access is invalid.
• Already exist data table
• Already exist network channel
• appendErrorMessage

AI-assisted analysis of EllanJiang/GameFramework@d0c010b051 (2026-09-15). Data as JSON: /api/errors/87e32308019f1f5d. Report an issue: GitHub.

Appendix: source

Thrown at GameFramework/Base/GameFrameworkLinkedList.cs:307

        /// <summary>
        /// 从链表中移除指定的结点。
        /// </summary>
        /// <param name="node">指定的结点。</param>
        public void Remove(LinkedListNode<T> node)
        {
            m_LinkedList.Remove(node);
            ReleaseNode(node);
        }

        /// <summary>
        /// 移除位于链表开头处的结点。
        /// </summary>
        public void RemoveFirst()
        {
            LinkedListNode<T> first = m_LinkedList.First;
            if (first == null)
            {
                throw new GameFrameworkException("First is invalid.");
            }

            m_LinkedList.RemoveFirst();
            ReleaseNode(first);
        }

        /// <summary>
        /// 移除位于链表结尾处的结点。
        /// </summary>
        public void RemoveLast()
        {
            LinkedListNode<T> last = m_LinkedList.Last;
            if (last == null)
            {
                throw new GameFrameworkException("Last is invalid.");
            }

            m_LinkedList.RemoveLast();

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