1 files changed, 56 insertions, 0 deletions
diff --git a/scripts/database/migration_collision_checker.rb b/scripts/database/migration_collision_checker.rb
new file mode 100644
index 00000000000..0c9daee9f4c
--- /dev/null
+++ b/scripts/database/migration_collision_checker.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+require 'pathname'
+require 'open3'
+
+# Checks for class name collisions between Database migrations and Elasticsearch migrations
+class MigrationCollisionChecker
+  MIGRATION_FOLDERS = %w[db/migrate/*.rb db/post_migrate/*.rb ee/elastic/migrate/*.rb].freeze
+
+  CLASS_MATCHER = /^\s*class\s+:*([A-Z][A-Za-z0-9_]+\S+)/
+
+  ERROR_CODE = 1
+
+  # To be removed in https://gitlab.com/gitlab-org/gitlab/-/merge_requests/129012
+  SKIP_MIGRATIONS = %w[AddInternalToNotes BackfillInternalOnNotes].freeze
+
+  Result = Struct.new(:error_code, :error_message)
+
+  def initialize
+    @collisions = Hash.new { |h, k| h[k] = [] }
+  end
+
+  def check
+    check_for_collisions
+
+    return if collisions.empty?
+
+    Result.new(ERROR_CODE, "\e[31mError: Naming collisions were found between migrations\n\n#{message}\e[0m")
+  end
+
+  private
+
+  attr_reader :collisions
+
+  def check_for_collisions
+    MIGRATION_FOLDERS.each do |migration_folder|
+      Dir.glob(base_path.join(migration_folder)).each do |migration_path|
+        klass_name = CLASS_MATCHER.match(File.read(migration_path))[1]
+
+        next if SKIP_MIGRATIONS.include?(klass_name)
+
+        collisions[klass_name] << migration_path
+      end
+    end
+
+    collisions.select! { |_, v| v.size > 1 }
+  end
+
+  def message
+    collisions.map { |klass_name, paths| "#{klass_name}: #{paths.join(', ')}\n" }.join('')
+  end
+
+  def base_path
+    Pathname.new(File.expand_path('../../', __dir__))
+  end
+end