Describe your environment
PHP 8.2.28, but this bug should not relevant with PHP version.

Steps to reproduce
After detached ContextStorageNode, it will reference itself as the previous node:

if ($this === $this->head->node) {
    assert($this->previous !== $this);
    $this->head->node = $this->previous;
    $this->previous = $this;

    return $flags;
}

Which cause circular reference to holding the memory.

What is the expected behavior?

Use WeakReference to avoid it.

if ($this === $this->head->node) {
    assert($this->previous !== $this);
    $this->head->node = $this->previous;
    $this->previous = WeakReference::create($this);

    return $flags;
}

What is the actual behavior?
Causing memory leak if we holding the process longer.

Additional context
Add any other context about the problem here.