instructure/canvas-lms · warning

Migration warning: #

Error message

Migration warning: #{user_message}: #{opts.inspect}

What it means

ContentMigration#add_warning records a non-fatal migration issue on the migration object and logs this warning line. The message interpolates the human-readable problem plus the opts hash, which often carries an exception or failing item info. It surfaces in the migration UI as a warning without stopping the import.

Solutions

1. Read the opts in the log/migration issues to identify the exact failed item (file, link, or exception)
2. Fix the source content (restore missing files/links) and re-run the migration
3. If a custom importer passes an Exception positionally, migrate to opts[:exception] / opts[:error_html] hash form
4. If warnings are spurious, trace which importer calls add_warning and adjust its pre-checks

Example fix

// before
migration.add_warning("file missing", some_exception) # deprecated positional arg
// after
migration.add_warning("file missing", exception: some_exception)

# pre-check referenced content before import
course.attachments.where(id: referenced_ids).missing.each do |a|
  migration.add_warning("missing attachment #{a.name}")
end

begin
  import_step
rescue => e
  migration.add_warning("step failed", exception: e)
end

When it happens

Trigger: Any migration step (attachment copy, missing content-link detection, importer callbacks) calls add_warning(message, opts) — e.g. an attachment failed to copy, a referenced file is missing, or a deprecated Exception argument was passed as the second parameter.

Common situations: Course copies where source files were deleted; broken links to missing wiki pages/quizzes; third-party importers passing exceptions via the deprecated two-arg form; locked/hidden files that cannot be copied.

Understand the failure class

Background: "is deprecated and will be removed" — deprecation warnings for old API names, keywords, and options, and how to migrate before the removal release — this error's family across 29 libraries.

Related errors

• The external Rubric couldn't be found for "#
• A partner ID is required to use Academic Benchmarks
• Child content tag was not found for #
• course hasn't been converted
• Do not look up MediaObjects by media_id - use the scope…

AI-assisted analysis of instructure/canvas-lms@1c9f0bb801 (2026-09-15). Data as JSON: /api/errors/49a2bad33ee1833c. Report an issue: GitHub.

Appendix: source

Thrown at app/models/content_migration.rb:321

      mi.delete
    else
      mi.save!
    end

    mi
  end

  def add_todo(user_message, opts = {})
    add_issue(user_message, :todo, opts)
  end

  def add_error(user_message, opts = {})
    level = opts.fetch(:issue_level, :error)
    add_issue(user_message, level, opts)
  end

  def add_warning(user_message, opts = {})
    Rails.logger.warn("Migration warning: #{user_message}: #{opts.inspect}")
    unless opts.is_a? Hash
      # convert deprecated behavior to new
      exception_or_info = opts
      opts = {}
      if exception_or_info.is_a?(Exception)
        opts[:exception] = exception_or_info
      else
        opts[:error_message] = exception_or_info
      end
    end
    add_issue(user_message, :warning, opts)
  end

  def add_unique_warning(key, warning, opts = {})
    @added_warnings ||= Set.new
    return if @added_warnings.include?(key) # only add it once

    @added_warnings << key

View on GitHub (pinned to 1c9f0bb801)