1 files changed, 104 insertions, 0 deletions
diff --git a/db/post_migrate/20170518231126_fix_wrongly_renamed_routes.rb b/db/post_migrate/20170518231126_fix_wrongly_renamed_routes.rb
new file mode 100644
index 00000000000..c78beda9d21
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+++ b/db/post_migrate/20170518231126_fix_wrongly_renamed_routes.rb
@@ -0,0 +1,104 @@
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class FixWronglyRenamedRoutes < ActiveRecord::Migration
+  include Gitlab::Database::RenameReservedPathsMigration::V1
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  DISALLOWED_ROOT_PATHS = %w[
+    -
+    abuse_reports
+    api
+    autocomplete
+    explore
+    health_check
+    import
+    invites
+    jwt
+    koding
+    member
+    notification_settings
+    oauth
+    sent_notifications
+    unicorn_test
+    uploads
+    users
+  ]
+
+  FIXED_PATHS = DISALLOWED_ROOT_PATHS.map { |p| "#{p}0" }
+
+  class Route < Gitlab::Database::RenameReservedPathsMigration::V1::MigrationClasses::Route
+    self.table_name = 'routes'
+  end
+
+  def routes
+    @routes ||= Route.arel_table
+  end
+
+  def namespaces
+    @namespaces ||= Arel::Table.new(:namespaces)
+  end
+
+  def wildcard_collection(collection)
+    collection.map { |word| "#{word}%" }
+  end
+
+  # The routes that got incorrectly renamed before, still have a namespace that
+  # contains the correct path.
+  # This query fetches all rows from the `routes` table that meet the following
+  # conditions using `api` as an example:
+  # - route.path ILIKE `api0%`
+  # - route.source_type = `Namespace`
+  # - namespace.parent_id IS NULL
+  # - namespace.path ILIKE `api%`
+  # - NOT(namespace.path ILIKE `api0%`)
+  # This gives us all root-routes, that were renamed, but their namespace was not.
+  #
+  def wrongly_renamed
+    Route.joins("INNER JOIN namespaces ON routes.source_id = namespaces.id")
+      .where(
+        routes[:source_type].eq('Namespace')
+          .and(namespaces[:parent_id].eq(nil))
+      )
+      .where(namespaces[:path].matches_any(wildcard_collection(DISALLOWED_ROOT_PATHS)))
+      .where.not(namespaces[:path].matches_any(wildcard_collection(FIXED_PATHS)))
+      .where(routes[:path].matches_any(wildcard_collection(FIXED_PATHS)))
+  end
+
+  # Using the query above, we just fetch the `route.path` & the `namespace.path`
+  # `route.path` is the part of the route that is now incorrect
+  # `namespace.path` is what it should be
+  # We can use `route.path` to find all the namespaces that need to be fixed
+  # And we can use `namespace.path` to apply the correct name.
+  #
+  def paths_and_corrections
+    connection.select_all(
+      wrongly_renamed.select(routes[:path], namespaces[:path].as('namespace_path')).to_sql
+    )
+  end
+
+  # This can be used to limit the `update_in_batches` call to all routes for a
+  # single namespace, note the `/` that's what went wrong in the initial migration.
+  #
+  def routes_in_namespace_query(namespace)
+    routes[:path].matches_any([namespace, "#{namespace}/%"])
+  end
+
+  def up
+    paths_and_corrections.each do |root_namespace|
+      wrong_path = root_namespace['path']
+      correct_path = root_namespace['namespace_path']
+      replace_statement = replace_sql(Route.arel_table[:path], wrong_path, correct_path)
+
+      update_column_in_batches(:routes, :path, replace_statement) do |table, query|
+        query.where(routes_in_namespace_query(wrong_path))
+      end
+    end
+  end
+
+  def down
+  end
+end