Make a vessel's children spill into its parent when it is deleted

[microlith57]

Current behaviour

A
- B
  - CD

delete B

A
C
D

(All paradoxes)

Proposed behaviour

A
- B
  - CD

delete B

A
- CD

(C and D children of A)

[microlith57]

def delete(id)
  @vessels.delete self[id]
  (0...@vessels.size).each do |v_id|
    v = self[v_id]
    # Decrement parents / orphan vessels as needed
    v.parent -= 1 if v.parent > id
    v.parent = v_id if v.parent == id
    # Decrement owners / disown vessels as needed
    v.owner -= 1 if v.owner > id
    v.owner = v_id if v.owner == id
  end
end

-->

def delete(id)
 to_delete = self[id]
  @vessels.delete to_delete
  (0...@vessels.size).each do |v_id|
    v = self[v_id]
    # Decrement parents / orphan vessels as needed
    v.parent -= 1 if v.parent > id
    if v.parent == id
      if to_delete.parent == id
        # Deleted vessel is a paradox
        v.parent = v_id
      else
        v.parent = to_delete.parent
      end
    end
    # Decrement owners / disown vessels as needed
    v.owner -= 1 if v.owner > id
    v.owner = v_id if v.owner == id
  end
end

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