Fix root node siblings not reordered after prepend_child/add_sibling moves root to child position

[Copilot]

Moving a root node to become a child via prepend_child or add_sibling leaves gaps in order_value sequence among remaining roots. The _ct_skip_sort_order_maintenance! flag prevents the normal reordering callback, but neither method was explicitly reordering the old parent's siblings afterward.

Changes

• New helper _ct_reorder_prior_parent_or_roots: Reorders either the prior parent's children or root siblings (when root ordering is enabled)
• prepend_child: Tracks prior parent before move, calls helper after save
• add_sibling: Tracks if sibling was root, uses helper instead of prior_sibling_parent.try(:_ct_reorder_children)

Example

node_1 = Label.create(name: 'node_1')  # order_value: 0
node_2 = Label.create(name: 'node_2')  # order_value: 1
node_3 = Label.create(name: 'node_3')  # order_value: 2
node_4 = Label.create(name: 'node_4')  # order_value: 3

node_3.prepend_child(node_2)

# Before fix: node_1=0, node_3=2, node_4=3 (gap at 1)
# After fix:  node_1=0, node_3=1, node_4=2 (sequential)

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• api.launchpad.net
  • Triggering command: /usr/bin/add-apt-repository add-apt-repository -y ppa:brightbox/ruby-ng (dns block)
• esm.ubuntu.com
  • Triggering command: /usr/lib/apt/methods/https /usr/lib/apt/methods/https (dns block)
• mise.run
  • Triggering command: /usr/bin/curl curl -fsSL REDACTED (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Root node siblings not reordered after prepend_child/add_sibling moves a root to child position</issue_title>
<issue_description>When using prepend_child or add_sibling to move a root-level node to become a child of another node, the remaining root nodes' order_value positions are not reordered, leaving gaps in the sequence.

Steps to Reproduce

Example 1: Using prepend_child

node_1 = Label.create(name: 'node_1')  # order_value: 0
node_2 = Label.create(name: 'node_2')  # order_value: 1
node_3 = Label.create(name: 'node_3')  # order_value: 2
node_4 = Label.create(name: 'node_4')  # order_value: 3

# Move node_2 as a child of node_3
node_3.prepend_child(node_2)

# Reload nodes
[node_1, node_2, node_3, node_4].each(&:reload)

Example 2: Using add_sibling

node_1 = Label.create(name: 'node_1')  # order_value: 0
node_2 = Label.create(name: 'node_2')  # order_value: 1
node_3 = Label.create(name: 'node_3')  # order_value: 2
node_4 = Label.create(name: 'node_4')  # order_value: 3

# Create a child under node_3
child = Label.create(name: 'child', parent: node_3)  # order_value: 0

# Move node_2 as a sibling of child (making it a child of node_3)
child.add_sibling(node_2)

# Reload nodes
[node_1, node_2, node_3, node_4].each(&:reload)

Expected Behavior

Remaining root nodes should have sequential order_value without gaps:

- node_1.order_value → 0
- node_3.order_value → 1
- node_4.order_value → 2

Actual Behavior

Root nodes retain their original positions, creating a gap:

- node_1.order_value → 0
- node_3.order_value → 2
- node_4.order_value → 3

Root Cause

Both prepend_child and add_sibling method calls _ct_skip_sort_order_maintenance! which prevents the normal callback _ct_reorder_prior_siblings_if_parent_changed from running. This flag is necessary to avoid double-reordering when setting up the child's position, but it has the side effect of not reordering the old parent's remaining children.

Test Cases

  # test/closure_tree/label_order_value_test.rb
  test 'should reorder remaining root nodes when a root node becomes a child via prepend_child' do
    node_1 = Label.create(name: 'node_1')
    node_2 = Label.create(name: 'node_2')
    node_3 = Label.create(name: 'node_3')
    node_4 = Label.create(name: 'node_4')

    # Verify initial positions
    assert_equal 0, node_1.order_value
    assert_equal 1, node_2.order_value
    assert_equal 2, node_3.order_value
    assert_equal 3, node_4.order_value

    # Move node_2 as a child of node_3 using prepend_child
    node_3.prepend_child(node_2)

    # Reload all nodes to get updated positions
    node_1.reload
    node_2.reload
    node_3.reload
    node_4.reload

    # Verify node_2 is now a child of node_3 with position 0
    assert_equal node_3.id, node_2._ct_parent_id
    assert_equal 0, node_2.order_value

    # Verify remaining root nodes have sequential positions without gaps
    assert_equal 0, node_1.order_value
    assert_equal 1, node_3.order_value
    assert_equal 2, node_4.order_value
  end

  test 'should reorder remaining root nodes when a root node becomes a child via add_sibling' do
    node_1 = Label.create(name: 'node_1')
    node_2 = Label.create(name: 'node_2')
    node_3 = Label.create(name: 'node_3')
    node_4 = Label.create(name: 'node_4')

    # Create a child under node_3
    child = Label.create(name: 'child', parent: node_3)

    # Verify initial positions
    assert_equal 0, node_1.order_value
    assert_equal 1, node_2.order_value
    assert_equal 2, node_3.order_value
    assert_equal 3, node_4.order_value
    assert_equal 0, child.order_value

    # Move node_2 as a sibling of child (making it a child of node_3)
    child.add_sibling(node_2)

    # Reload all nodes to get updated positions
    node_1.reload
    node_2.reload
    node_3.reload
    node_4.reload

    # Verify node_2 is now a child of node_3
    assert_equal node_3.id, node_2._ct_parent_id

    # Verify remaining root nodes have sequential positions without gaps
    assert_equal 0, node_1.order_value
    assert_equal 1, node_3.order_value
    assert_equal 2, node_4.order_value
  end
```</issue_description>

## Comments on the Issue (you are @copilot in this section)

<comments>
</comments>

• Fixes Root node siblings not reordered after prepend_child/add_sibling moves a root to child position #481

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.