voormedia/rails-erd · error

Unknown generator: #{RailsERD.options.generator}

Error message

Unknown generator: #{RailsERD.options.generator}

What it means

Error "Unknown generator: #{RailsERD.options.generator}" thrown in voormedia/rails-erd.

Source

Thrown at lib/rails_erd/tasks.rake:80

    end

    raise "Active Record was not loaded." unless defined? ActiveRecord
  end

  task :generate => [:options, :check_dependencies, :load_models] do
    include ErdRakeHelper

    say "Generating Entity-Relationship Diagram for #{ActiveRecord::Base.descendants.length} models..."

    file = case RailsERD.options.generator
    when :mermaid
      require "rails_erd/diagram/mermaid"
      RailsERD::Diagram::Mermaid.create
    when :graphviz
      require "rails_erd/diagram/graphviz"
      RailsERD::Diagram::Graphviz.create
    else
      raise "Unknown generator: #{RailsERD.options.generator}"
    end


    say "Done! Saved diagram to ./#{file}"
  end
end

desc "Generate an Entity-Relationship Diagram based on your models"
task :erd => "erd:generate"

View on GitHub (pinned to dae6e52018)

Solutions

1. Pass a supported generator: `bundle exec rake erd generator=graphviz` (default) or `bundle exec rake erd generator=mermaid`.
2. Check the `generator` environment variable for typos; valid values are `graphviz` and `mermaid`.

Example fix

bundle exec rake erd generator=mermaid

When it happens

Trigger: Raised in the erd:generate rake task when RailsERD.options.generator is neither :mermaid nor :graphviz, e.g. passing an unsupported generator value such as `generator=tbls` on the command line.

Common situations: See trigger scenarios.

AI-assisted analysis of voormedia/rails-erd@dae6e52018 (2026-08-23). Data as JSON: /api/errors/7bfa0215f4f5a576. Report an issue: GitHub.