Fix errors when viewing version history of deleted domains

.gitignore

@@ -35,4 +35,6 @@ CLAUDE.md
 .claude/
 .memory-bank
 AGENT.md
-own
+own
+AGENT.md
+

app/controllers/admin/domain_versions_controller.rb

@@ -61,10 +61,12 @@ def show
         @domain = Domain.find(params[:domain_id] || params[:id])
       else
         @version = Version::DomainVersion.find(params[:id])
-        @domain = Domain.find(@version.item_id)
+        @resolver = Version::DomainVersion::Resolver.new(@version)
+        @domain = @resolver.domain
       end
 
-      @versions = Version::DomainVersion.where(item_id: @domain.id).order(created_at: :desc, id: :desc)
+      item_id = @resolver&.item_id || @domain.id
+      @versions = Version::DomainVersion.where(item_id: item_id).order(created_at: :desc, id: :desc)
       @versions_map = @versions.all.map(&:id)
 
       get_page if params[:page].blank?

app/models/version/domain_version/resolver.rb

@@ -0,0 +1,102 @@
+class Version::DomainVersion < PaperTrail::Version
+  class Resolver
+    attr_reader :version
+
+    def initialize(version)
+      @version = version
+    end
+
+    def domain
+      @domain ||= live_domain || reconstruct_domain
+    end
+
+    def deleted?
+      live_domain.nil?
+    end
+
+    def domain_name
+      domain.name.presence || object_value('name') || changes_value('name')
+    end
+
+    def registrar
+      return @registrar if defined?(@registrar)
+
+      @registrar = registrar_id && Registrar.find_by(id: registrar_id)
+    end
+
+    def registrar_id
+      domain.registrar_id || changes_value('registrar_id') || object_value('registrar_id')
+    end
+
+    def item_id
+      version.item_id
+    end
+
+    private
+
+    def live_domain
+      return @live_domain if defined?(@live_domain)
+
+      @live_domain = Domain.find_by(id: version.item_id)
+    end
+
+    def reconstruct_domain
+      reify_with_changes || earliest_reifiable_version&.reify || build_from_changes
+    end
+
+    def reify_with_changes
+      reified = version.reify
+      return nil unless reified
+
+      apply_changes(reified)
+      stamp_timestamps(reified)
+      reified
+    end
+
+    def earliest_reifiable_version
+      sibling_versions.where.not(object: nil).first
+    end
+
+    def build_from_changes
+      record = Domain.new
+      apply_changes(record)
+      stamp_timestamps(record)
+      record
+    end
+
+    def apply_changes(record)
+      changes = version.object_changes || {}
+      changes.slice(*Domain.column_names).each do |attr, values|
+        value = values.is_a?(Array) ? values.last : values
+        record.public_send("#{attr}=", value)
+      end
+    end
+
+    def stamp_timestamps(record)
+      record.created_at ||= earliest_version_created_at
+      record.updated_at ||= version.created_at
+    end
+
+    def earliest_version_created_at
+      @earliest_version_created_at ||=
+        sibling_versions.pluck(:created_at).first || version.created_at
+    end
+
+    def sibling_versions
+      Version::DomainVersion
+        .where(item_id: version.item_id)
+        .order(created_at: :asc, id: :asc)
+    end
+
+    def object_value(key)
+      version.object.is_a?(Hash) ? version.object[key] : nil
+    end
+
+    def changes_value(key)
+      changes = version.object_changes
+      return nil unless changes.is_a?(Hash) && changes[key].is_a?(Array)
+
+      changes[key].last
+    end
+  end
+end

app/views/admin/domain_versions/show.haml

@@ -1,10 +1,12 @@
+- deleted = @resolver&.deleted?
 - if @version
   - children = HashWithIndifferentAccess.new(@version.children)
-  - nameservers    = Nameserver.all_versions_for(children[:nameservers], @domain.updated_at)
-  - dnskeys        = Dnskey.all_versions_for(children[:dnskeys], @domain.updated_at)
-  - tech_contacts  = Contact.all_versions_for(children[:tech_contacts], @domain.updated_at)
-  - admin_contacts = Contact.all_versions_for(children[:admin_contacts], @domain.updated_at)
-  - registrant     = Contact.all_versions_for(children[:registrant], @domain.updated_at)
+  - version_timestamp = @domain.updated_at || @version.created_at
+  - nameservers    = Nameserver.all_versions_for(children[:nameservers], version_timestamp)
+  - dnskeys        = Dnskey.all_versions_for(children[:dnskeys], version_timestamp)
+  - tech_contacts  = Contact.all_versions_for(children[:tech_contacts], version_timestamp)
+  - admin_contacts = Contact.all_versions_for(children[:admin_contacts], version_timestamp)
+  - registrant     = Contact.all_versions_for(children[:registrant], version_timestamp)
   - event       = @version.event
   - creator     = plain_username(@version.terminator)
 - else
@@ -33,19 +35,17 @@
       .panel-body
         %dl.dl-horizontal
           %dt= t(:name)
-          - if !@domain.name
-            - domain_name = Domain.find(@version.item_id).try(:name)
+          - domain_name = (@resolver ? @resolver.domain_name : @domain.name).presence || t('.unknown_name')
+          - if deleted
+            %dd= domain_name
           - else
-            - domain_name = @domain.name
-          %dd= link_to(domain_name, admin_domain_path(@version ? @version.item_id : @domain.id))
+            %dd= link_to(domain_name, admin_domain_path(@version ? @version.item_id : @domain.id))
 
           %dt= t('.created')
-          %dd
-            = l(@domain.created_at, format: :short)
+          %dd= l(@domain.created_at, format: :short)
 
           %dt= t('.updated')
-          %dd
-            = l(@domain.updated_at, format: :short)
+          %dd= l(@domain.updated_at, format: :short)
 
           %br
 
@@ -112,12 +112,18 @@
                 \...#{ns[:public_key].to_s[-20,20]}
             %br
 
-          - if @domain.registrar
+          - registrar = @resolver ? @resolver.registrar : @domain.registrar
+          - registrar_id = @resolver ? @resolver.registrar_id : @domain.registrar&.id
+          - if registrar
+            %dt= t(:registrar_name)
+            %dd{class: changing_css_class(@version,"registrar_id")}
+              = link_to admin_registrar_path(registrar), target: "registrar_#{registrar.id}" do
+                = registrar.name
+          - elsif registrar_id
             %dt= t(:registrar_name)
             %dd{class: changing_css_class(@version,"registrar_id")}
-              = link_to admin_registrar_path(@domain.registrar), target: "registrar_#{@domain.registrar.id}" do
-                = @domain.registrar.name
-            %span{:style => "margin: 20px 20px; clear:both;"}
+              = "Registrar ID: #{registrar_id}"
+          %span{:style => "margin: 20px 20px; clear:both;"}
 
         - if @version && (prev = @versions_map[(@versions_map.index(@version.id) - 1)]) && @versions_map.index(@version.id) != 0
           = link_to(t(:previous),
@@ -137,8 +143,9 @@
   .col-md-4
     .panel.panel-default{:style => "min-height:450px;"}
       %ul.nav.nav-pills.nav-stacked
-        %li{class: ('active' if @version.nil?)}
-          = link_to t('.current_state'), admin_domain_version_path(current: 1, domain_id: @domain.id)
+        - unless deleted
+          %li{class: ('active' if @version.nil?)}
+            = link_to t('.current_state'), admin_domain_version_path(current: 1, domain_id: @domain.id)
         - @versions.each do |vs|
           %li{class: (@version && vs.id == @version.id) && :active}
             = link_to admin_domain_version_path(vs) do

config/locales/admin/domain_versions.en.yml

@@ -14,3 +14,4 @@ en:
         admin_contacts: Admin. contacts
         tech_contacts: Tech. contacts
         current_state: Current state
+        unknown_name: N/A

test/integration/admin_area/domain_versions_controller_test.rb

@@ -137,4 +137,108 @@ def test_show_with_invalid_domain_id
       get admin_domain_version_path(999999), params: { current: true }
     end
   end
+
+  def test_show_create_version_of_deleted_domain
+    deleted_item_id = next_unused_domain_id
+    create_version = Version::DomainVersion.create!(
+      item_type: 'Domain',
+      item_id: deleted_item_id,
+      event: 'create',
+      whodunnit: users(:admin).id.to_s,
+      object: nil,
+      object_changes: {
+        'name' => [nil, 'ghost.test'],
+        'registrar_id' => [nil, @registrar.id],
+        'registrant_id' => [nil, contacts(:john).id],
+      },
+      created_at: Time.zone.parse('2024-01-01')
+    )
+
+    get admin_domain_version_path(create_version.id)
+
+    assert_response :ok
+    assert_includes response.body, 'ghost.test'
+    assert_includes response.body, @registrar.name
+    assert_no_match %r{href="#{admin_domain_path(deleted_item_id)}"}, response.body
+    assert_no_match %r{admin_domain_version[^"]*current=1}, response.body
+  end
+
+  def test_show_update_version_of_deleted_domain
+    deleted_item_id = next_unused_domain_id
+    Version::DomainVersion.create!(
+      item_type: 'Domain',
+      item_id: deleted_item_id,
+      event: 'create',
+      whodunnit: users(:admin).id.to_s,
+      object: nil,
+      object_changes: {
+        'name' => [nil, 'gone.test'],
+        'registrar_id' => [nil, @registrar.id],
+      },
+      created_at: Time.zone.parse('2024-01-01')
+    )
+    update_version = Version::DomainVersion.create!(
+      item_type: 'Domain',
+      item_id: deleted_item_id,
+      event: 'update',
+      whodunnit: users(:admin).id.to_s,
+      object: {
+        'name' => 'gone.test',
+        'registrar_id' => @registrar.id,
+      },
+      object_changes: {
+        'statuses' => [[], ['serverHold']],
+      },
+      created_at: Time.zone.parse('2024-02-01')
+    )
+
+    get admin_domain_version_path(update_version.id)
+
+    assert_response :ok
+    assert_includes response.body, 'gone.test'
+    assert_includes response.body, @registrar.name
+    assert_no_match %r{href="#{admin_domain_path(deleted_item_id)}"}, response.body
+  end
+
+  def test_show_destroy_version_of_deleted_domain
+    deleted_item_id = next_unused_domain_id
+    Version::DomainVersion.create!(
+      item_type: 'Domain',
+      item_id: deleted_item_id,
+      event: 'create',
+      whodunnit: users(:admin).id.to_s,
+      object: nil,
+      object_changes: {
+        'name' => [nil, 'bye.test'],
+        'registrar_id' => [nil, @registrar.id],
+      },
+      created_at: Time.zone.parse('2024-01-01')
+    )
+    destroy_version = Version::DomainVersion.create!(
+      item_type: 'Domain',
+      item_id: deleted_item_id,
+      event: 'destroy',
+      whodunnit: users(:admin).id.to_s,
+      object: {
+        'name' => 'bye.test',
+        'registrar_id' => @registrar.id,
+      },
+      object_changes: nil,
+      created_at: Time.zone.parse('2024-03-01')
+    )
+
+    get admin_domain_version_path(destroy_version.id)
+
+    assert_response :ok
+    assert_includes response.body, 'bye.test'
+  end
+
+  private
+
+  def next_unused_domain_id
+    @next_unused_domain_id ||= Domain.maximum(:id).to_i +
+                               Version::DomainVersion.maximum(:item_id).to_i +
+                               1000
+    @next_unused_domain_id += 1
+  end
 end