# Rails and hanami-view don't get along

**URL:** <https://discourse.hanakai.org/t/rails-and-hanami-view-dont-get-along/1122>\
**Category:** questions\
**Created:** [February 16, 2025, 2:22pm UTC](https://discourse.hanakai.org/t/rails-and-hanami-view-dont-get-along/1122 "2025-02-16T14:22:41Z")\
**Posts on this page:** 9\
**Page:** 1

<div class="post-metadata">

**Author:** ![stephan](https://avatars.discourse-cdn.com/v4/letter/s/8baadc/32.png) [@stephan](https://discourse.hanakai.org/u/stephan)\
**Post date:** [February 16, 2025, 2:22pm UTC](https://discourse.hanakai.org/t/rails-and-hanami-view-dont-get-along/1122/1 "2025-02-16T14:22:41Z")

</div>

After more help from @cllns in [Trouble testing the result of an operation - #2 by cllns](https://discourse.hanakai.org/t/trouble-testing-the-result-of-an-operation/1121/2) I am now looking at a gem dependency incompatibility between Rails and hanami-view and Hanami-controller. Here is a minimal repro:

```auto
rm -rf hanami_sample3

rails new hanami_sample3
cd hanami_sample3

rails generate rspec:install
bundle exec rails g scaffold team name:string

echo '
gem "hanami", github: "hanami/hanami", branch: "fix-error-in-operation-extension-for-no-db-apps"
gem "hanami-controller", "~> 2.2"
gem "hanami-view", "~> 2.2"
gem "dry-operation"
' >> Gemfile

bundle

cd tmp
bundle exec hanami new SportsballHanami
cd sportsball_hanami
bundle exec hanami generate slice HanamiPredictor
mv slices ../..

cd ../..

echo '# typed: ignore

require "dry/monads"
require "dry/operation"
require "hanami/action"
require "hanami/view"

module SportsballHanami
  class App < Hanami::App
    prepare_container do |container|
      container.autoloader.ignore("app")
    end
  end

  class Action < Hanami::Action
    include Dry::Monads[:result]
  end
end

Hanami.boot

module SportsballHanami
  class View < Hanami::View
  end

  class Operation < Dry::Operation
  end
end

HanamiPredictor::Slice.boot

p Hanami.app.slices[:hanami_predictor].keys

' > config/initializers/load_hanami.rb

bin/rails runner 'puts "Hello, world!"'
bin/rails db:migrate
bin/rails s

```

Navigate to `http://localhost:3000/teams` (edit: as @alassek points out, this page still works… but navigate to the _new team page_ to see the error) and see the following error:

```auto
undefined method `safe_concat' for "<form action=\"/teams\" accept-charset=\"UTF-8\" method=\"post\"><input type=\"hidden\" name=\"authenticity_token\" value=\"rO7x6c8gR4aowONfekEg6ZbzLCTCF_iBmBKoeDr_hF0p958zbP8jzxw-x_KJRtOfDro3GlSnHoswMjcY8R4w9Q\" autocomplete=\"off\" />\n\n <div>\n <label style=\"display: block\" for=\"team_name\">Name</label>\n <input type=\"text\" name=\"team[name]\" id=\"team_name\" />\n </div>\n\n <div>\n <input type=\"submit\" name=\"commit\" value=\"Create Team\" data-disable-with=\"Create Team\" />\n </div>\n":String

```

When I make the following changes, the app works again (I am not sure this is minimal):

- comment out `hanami-controller` and `hanami-view` in the Gemfile
- remove the `require` of `hanami/action` and `hanami/view` in the initializer
- remove the subclassing of `Hanami::Action` and `Hanami::View`

My current theory is that it is the version of `rack` or `rackup` which are held back a major version by `hanami-controller` depending on `rack (~> 2.0)`. If that were the only explanation though, I am not sure why I have to remove the view pieces above as well…

---

<div class="post-metadata">

**Author:** ![alassek](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.hanakai.org/alassek/32/532_2.png) [@alassek](https://discourse.hanakai.org/u/alassek)\
**Post date:** [February 17, 2025, 12:12am UTC](https://discourse.hanakai.org/t/rails-and-hanami-view-dont-get-along/1122/2 "2025-02-17T00:12:20Z")

</div>

Following your steps, I was unable to reproduce.

```console
Started GET "/teams" for 127.0.0.1 at 2025-02-16 18:07:40 -0600
  ActiveRecord::SchemaMigration Load (0.0ms) SELECT "schema_migrations"."version" FROM "schema_migrations" ORDER BY "schema_migrations"."version" ASC /*application='Viewtest'*/
Processing by TeamsController#index as HTML
  Rendering layout layouts/application.html.erb
  Rendering teams/index.html.erb within layouts/application
  Team Load (0.4ms) SELECT "teams".* FROM "teams" /*action='index',application='Viewtest',controller='teams'*/
  ↳ app/views/teams/index.html.erb:8
  Rendered teams/index.html.erb within layouts/application (Duration: 2.3ms | GC: 0.0ms)
  Rendered layout layouts/application.html.erb (Duration: 6.7ms | GC: 0.0ms)
Completed 200 OK in 58ms (Views: 8.8ms | ActiveRecord: 0.5ms (1 query, 0 cached) | GC: 0.0ms)

```

This was a fresh install of:

- Ruby 3.4.2
- Rails 8.0.1
- Hanami 2.2.1

```auto
GIT
  remote: https://github.com/hanami/hanami.git
  revision: 27a002cd91c24b67ab67ab7f11698314b90dd446
  branch: fix-error-in-operation-extension-for-no-db-apps
  specs:
    hanami (2.2.1)
      bundler (>= 1.16, < 3)
      dry-configurable (~> 1.0, >= 1.2.0, < 2)
      dry-core (~> 1.0, < 2)
      dry-inflector (~> 1.0, >= 1.1.0, < 2)
      dry-logger (~> 1.0, < 2)
      dry-monitor (~> 1.0, >= 1.0.1, < 2)
      dry-system (~> 1.1)
      hanami-cli (~> 2.2.1)
      hanami-utils (~> 2.2)
      json (>= 2.7.2)
      zeitwerk (~> 2.6)

GEM
  remote: https://rubygems.org/
  specs:
    actioncable (8.0.1)
      actionpack (= 8.0.1)
      activesupport (= 8.0.1)
      nio4r (~> 2.0)
      websocket-driver (>= 0.6.1)
      zeitwerk (~> 2.6)
    actionmailbox (8.0.1)
      actionpack (= 8.0.1)
      activejob (= 8.0.1)
      activerecord (= 8.0.1)
      activestorage (= 8.0.1)
      activesupport (= 8.0.1)
      mail (>= 2.8.0)
    actionmailer (8.0.1)
      actionpack (= 8.0.1)
      actionview (= 8.0.1)
      activejob (= 8.0.1)
      activesupport (= 8.0.1)
      mail (>= 2.8.0)
      rails-dom-testing (~> 2.2)
    actionpack (8.0.1)
      actionview (= 8.0.1)
      activesupport (= 8.0.1)
      nokogiri (>= 1.8.5)
      rack (>= 2.2.4)
      rack-session (>= 1.0.1)
      rack-test (>= 0.6.3)
      rails-dom-testing (~> 2.2)
      rails-html-sanitizer (~> 1.6)
      useragent (~> 0.16)
    actiontext (8.0.1)
      actionpack (= 8.0.1)
      activerecord (= 8.0.1)
      activestorage (= 8.0.1)
      activesupport (= 8.0.1)
      globalid (>= 0.6.0)
      nokogiri (>= 1.8.5)
    actionview (8.0.1)
      activesupport (= 8.0.1)
      builder (~> 3.1)
      erubi (~> 1.11)
      rails-dom-testing (~> 2.2)
      rails-html-sanitizer (~> 1.6)
    activejob (8.0.1)
      activesupport (= 8.0.1)
      globalid (>= 0.3.6)
    activemodel (8.0.1)
      activesupport (= 8.0.1)
    activerecord (8.0.1)
      activemodel (= 8.0.1)
      activesupport (= 8.0.1)
      timeout (>= 0.4.0)
    activestorage (8.0.1)
      actionpack (= 8.0.1)
      activejob (= 8.0.1)
      activerecord (= 8.0.1)
      activesupport (= 8.0.1)
      marcel (~> 1.0)
    activesupport (8.0.1)
      base64
      benchmark (>= 0.3)
      bigdecimal
      concurrent-ruby (~> 1.0, >= 1.3.1)
      connection_pool (>= 2.2.5)
      drb
      i18n (>= 1.6, < 2)
      logger (>= 1.4.2)
      minitest (>= 5.1)
      securerandom (>= 0.3)
      tzinfo (~> 2.0, >= 2.0.5)
      uri (>= 0.13.1)
    addressable (2.8.7)
      public_suffix (>= 2.0.2, < 7.0)
    ast (2.4.2)
    base64 (0.2.0)
    bcrypt_pbkdf (1.1.1)
    benchmark (0.4.0)
    bigdecimal (3.1.9)
    bindex (0.8.1)
    bootsnap (1.18.4)
      msgpack (~> 1.2)
    brakeman (7.0.0)
      racc
    builder (3.3.0)
    capybara (3.40.0)
      addressable
      matrix
      mini_mime (>= 0.1.3)
      nokogiri (~> 1.11)
      rack (>= 1.6.0)
      rack-test (>= 0.6.3)
      regexp_parser (>= 1.5, < 3.0)
      xpath (~> 3.2)
    concurrent-ruby (1.3.5)
    connection_pool (2.5.0)
    crass (1.0.6)
    date (3.4.1)
    debug (1.10.0)
      irb (~> 1.10)
      reline (>= 0.3.8)
    diff-lcs (1.6.0)
    dotenv (3.1.7)
    drb (2.2.1)
    dry-auto_inject (1.1.0)
      dry-core (~> 1.1)
      zeitwerk (~> 2.6)
    dry-cli (1.2.0)
    dry-configurable (1.3.0)
      dry-core (~> 1.1)
      zeitwerk (~> 2.6)
    dry-core (1.1.0)
      concurrent-ruby (~> 1.0)
      logger
      zeitwerk (~> 2.6)
    dry-events (1.1.0)
      concurrent-ruby (~> 1.0)
      dry-core (~> 1.1)
    dry-files (1.1.0)
    dry-inflector (1.2.0)
    dry-logger (1.0.4)
    dry-monads (1.7.1)
      concurrent-ruby (~> 1.0)
      dry-core (~> 1.1)
      zeitwerk (~> 2.6)
    dry-monitor (1.0.1)
      dry-configurable (~> 1.0, < 2)
      dry-core (~> 1.0, < 2)
      dry-events (~> 1.0, < 2)
    dry-operation (1.0.0)
      dry-monads (~> 1.6)
      zeitwerk (~> 2.6)
    dry-system (1.2.2)
      dry-auto_inject (~> 1.1)
      dry-configurable (~> 1.3)
      dry-core (~> 1.1)
      dry-inflector (~> 1.1)
    dry-transformer (1.0.1)
      zeitwerk (~> 2.6)
    ed25519 (1.3.0)
    erubi (1.13.1)
    et-orbi (1.2.11)
      tzinfo
    fugit (1.11.1)
      et-orbi (~> 1, >= 1.2.11)
      raabro (~> 1.4)
    globalid (1.2.1)
      activesupport (>= 6.1)
    hanami-cli (2.2.1)
      bundler (~> 2.1)
      dry-cli (~> 1.0, >= 1.1.0)
      dry-files (~> 1.0, >= 1.0.2, < 2)
      dry-inflector (~> 1.0, < 2)
      rake (~> 13.0)
      zeitwerk (~> 2.6)
    hanami-controller (2.2.0)
      dry-configurable (~> 1.0, < 2)
      dry-core (~> 1.0)
      hanami-utils (~> 2.2)
      rack (~> 2.0)
      zeitwerk (~> 2.6)
    hanami-utils (2.2.0)
      concurrent-ruby (~> 1.0)
      dry-core (~> 1.0, < 2)
      dry-transformer (~> 1.0, < 2)
    hanami-view (2.2.0)
      dry-configurable (~> 1.0)
      dry-core (~> 1.0)
      dry-inflector (~> 1.0, < 2)
      temple (~> 0.10.0, >= 0.10.2)
      tilt (~> 2.3)
      zeitwerk (~> 2.6)
    i18n (1.14.7)
      concurrent-ruby (~> 1.0)
    importmap-rails (2.1.0)
      actionpack (>= 6.0.0)
      activesupport (>= 6.0.0)
      railties (>= 6.0.0)
    io-console (0.8.0)
    irb (1.15.1)
      pp (>= 0.6.0)
      rdoc (>= 4.0.0)
      reline (>= 0.4.2)
    jbuilder (2.13.0)
      actionview (>= 5.0.0)
      activesupport (>= 5.0.0)
    json (2.10.1)
    kamal (2.5.2)
      activesupport (>= 7.0)
      base64 (~> 0.2)
      bcrypt_pbkdf (~> 1.0)
      concurrent-ruby (~> 1.2)
      dotenv (~> 3.1)
      ed25519 (~> 1.2)
      net-ssh (~> 7.3)
      sshkit (>= 1.23.0, < 2.0)
      thor (~> 1.3)
      zeitwerk (>= 2.6.18, < 3.0)
    language_server-protocol (3.17.0.4)
    lint_roller (1.1.0)
    logger (1.6.6)
    loofah (2.24.0)
      crass (~> 1.0.2)
      nokogiri (>= 1.12.0)
    mail (2.8.1)
      mini_mime (>= 0.1.1)
      net-imap
      net-pop
      net-smtp
    marcel (1.0.4)
    matrix (0.4.2)
    mini_mime (1.1.5)
    minitest (5.25.4)
    msgpack (1.8.0)
    net-imap (0.5.6)
      date
      net-protocol
    net-pop (0.1.2)
      net-protocol
    net-protocol (0.2.2)
      timeout
    net-scp (4.1.0)
      net-ssh (>= 2.6.5, < 8.0.0)
    net-sftp (4.0.0)
      net-ssh (>= 5.0.0, < 8.0.0)
    net-smtp (0.5.1)
      net-protocol
    net-ssh (7.3.0)
    nio4r (2.7.4)
    nokogiri (1.18.2-aarch64-linux-gnu)
      racc (~> 1.4)
    nokogiri (1.18.2-aarch64-linux-musl)
      racc (~> 1.4)
    nokogiri (1.18.2-arm-linux-gnu)
      racc (~> 1.4)
    nokogiri (1.18.2-arm-linux-musl)
      racc (~> 1.4)
    nokogiri (1.18.2-arm64-darwin)
      racc (~> 1.4)
    nokogiri (1.18.2-x86_64-linux-gnu)
      racc (~> 1.4)
    nokogiri (1.18.2-x86_64-linux-musl)
      racc (~> 1.4)
    ostruct (0.6.1)
    parallel (1.26.3)
    parser (3.3.7.1)
      ast (~> 2.4.1)
      racc
    pp (0.6.2)
      prettyprint
    prettyprint (0.2.0)
    propshaft (1.1.0)
      actionpack (>= 7.0.0)
      activesupport (>= 7.0.0)
      rack
      railties (>= 7.0.0)
    psych (5.2.3)
      date
      stringio
    public_suffix (6.0.1)
    puma (6.6.0)
      nio4r (~> 2.0)
    raabro (1.4.0)
    racc (1.8.1)
    rack (2.2.11)
    rack-session (1.0.2)
      rack (< 3)
    rack-test (2.2.0)
      rack (>= 1.3)
    rackup (1.0.1)
      rack (< 3)
      webrick
    rails (8.0.1)
      actioncable (= 8.0.1)
      actionmailbox (= 8.0.1)
      actionmailer (= 8.0.1)
      actionpack (= 8.0.1)
      actiontext (= 8.0.1)
      actionview (= 8.0.1)
      activejob (= 8.0.1)
      activemodel (= 8.0.1)
      activerecord (= 8.0.1)
      activestorage (= 8.0.1)
      activesupport (= 8.0.1)
      bundler (>= 1.15.0)
      railties (= 8.0.1)
    rails-dom-testing (2.2.0)
      activesupport (>= 5.0.0)
      minitest
      nokogiri (>= 1.6)
    rails-html-sanitizer (1.6.2)
      loofah (~> 2.21)
      nokogiri (>= 1.15.7, != 1.16.7, != 1.16.6, != 1.16.5, != 1.16.4, != 1.16.3, != 1.16.2, != 1.16.1, != 1.16.0.rc1, != 1.16.0)
    railties (8.0.1)
      actionpack (= 8.0.1)
      activesupport (= 8.0.1)
      irb (~> 1.13)
      rackup (>= 1.0.0)
      rake (>= 12.2)
      thor (~> 1.0, >= 1.2.2)
      zeitwerk (~> 2.6)
    rainbow (3.1.1)
    rake (13.2.1)
    rdoc (6.12.0)
      psych (>= 4.0.0)
    regexp_parser (2.10.0)
    reline (0.6.0)
      io-console (~> 0.5)
    rexml (3.4.1)
    rspec-core (3.13.3)
      rspec-support (~> 3.13.0)
    rspec-expectations (3.13.3)
      diff-lcs (>= 1.2.0, < 2.0)
      rspec-support (~> 3.13.0)
    rspec-mocks (3.13.2)
      diff-lcs (>= 1.2.0, < 2.0)
      rspec-support (~> 3.13.0)
    rspec-rails (7.1.1)
      actionpack (>= 7.0)
      activesupport (>= 7.0)
      railties (>= 7.0)
      rspec-core (~> 3.13)
      rspec-expectations (~> 3.13)
      rspec-mocks (~> 3.13)
      rspec-support (~> 3.13)
    rspec-support (3.13.2)
    rubocop (1.72.1)
      json (~> 2.3)
      language_server-protocol (~> 3.17.0.2)
      lint_roller (~> 1.1.0)
      parallel (~> 1.10)
      parser (>= 3.3.0.2)
      rainbow (>= 2.2.2, < 4.0)
      regexp_parser (>= 2.9.3, < 3.0)
      rubocop-ast (>= 1.38.0, < 2.0)
      ruby-progressbar (~> 1.7)
      unicode-display_width (>= 2.4.0, < 4.0)
    rubocop-ast (1.38.0)
      parser (>= 3.3.1.0)
    rubocop-minitest (0.37.1)
      lint_roller (~> 1.1)
      rubocop (>= 1.72.1, < 2.0)
      rubocop-ast (>= 1.38.0, < 2.0)
    rubocop-performance (1.24.0)
      lint_roller (~> 1.1)
      rubocop (>= 1.72.1, < 2.0)
      rubocop-ast (>= 1.38.0, < 2.0)
    rubocop-rails (2.30.0)
      activesupport (>= 4.2.0)
      lint_roller (~> 1.1)
      rack (>= 1.1)
      rubocop (>= 1.72.1, < 2.0)
      rubocop-ast (>= 1.38.0, < 2.0)
    rubocop-rails-omakase (1.0.0)
      rubocop
      rubocop-minitest
      rubocop-performance
      rubocop-rails
    ruby-progressbar (1.13.0)
    rubyzip (2.4.1)
    securerandom (0.4.1)
    selenium-webdriver (4.28.0)
      base64 (~> 0.2)
      logger (~> 1.4)
      rexml (~> 3.2, >= 3.2.5)
      rubyzip (>= 1.2.2, < 3.0)
      websocket (~> 1.0)
    solid_cable (3.0.7)
      actioncable (>= 7.2)
      activejob (>= 7.2)
      activerecord (>= 7.2)
      railties (>= 7.2)
    solid_cache (1.0.7)
      activejob (>= 7.2)
      activerecord (>= 7.2)
      railties (>= 7.2)
    solid_queue (1.1.3)
      activejob (>= 7.1)
      activerecord (>= 7.1)
      concurrent-ruby (>= 1.3.1)
      fugit (~> 1.11.0)
      railties (>= 7.1)
      thor (~> 1.3.1)
    sqlite3 (2.5.0-aarch64-linux-gnu)
    sqlite3 (2.5.0-aarch64-linux-musl)
    sqlite3 (2.5.0-arm-linux-gnu)
    sqlite3 (2.5.0-arm-linux-musl)
    sqlite3 (2.5.0-arm64-darwin)
    sqlite3 (2.5.0-x86_64-linux-gnu)
    sqlite3 (2.5.0-x86_64-linux-musl)
    sshkit (1.24.0)
      base64
      logger
      net-scp (>= 1.1.2)
      net-sftp (>= 2.1.2)
      net-ssh (>= 2.8.0)
      ostruct
    stimulus-rails (1.3.4)
      railties (>= 6.0.0)
    stringio (3.1.3)
    temple (0.10.3)
    thor (1.3.2)
    thruster (0.1.11)
    thruster (0.1.11-aarch64-linux)
    thruster (0.1.11-arm64-darwin)
    thruster (0.1.11-x86_64-linux)
    tilt (2.6.0)
    timeout (0.4.3)
    turbo-rails (2.0.11)
      actionpack (>= 6.0.0)
      railties (>= 6.0.0)
    tzinfo (2.0.6)
      concurrent-ruby (~> 1.0)
    unicode-display_width (3.1.4)
      unicode-emoji (~> 4.0, >= 4.0.4)
    unicode-emoji (4.0.4)
    uri (1.0.2)
    useragent (0.16.11)
    web-console (4.2.1)
      actionview (>= 6.0.0)
      activemodel (>= 6.0.0)
      bindex (>= 0.4.0)
      railties (>= 6.0.0)
    webrick (1.9.1)
    websocket (1.2.11)
    websocket-driver (0.7.7)
      base64
      websocket-extensions (>= 0.1.0)
    websocket-extensions (0.1.5)
    xpath (3.2.0)
      nokogiri (~> 1.8)
    zeitwerk (2.7.1)

PLATFORMS
  aarch64-linux
  aarch64-linux-gnu
  aarch64-linux-musl
  arm-linux-gnu
  arm-linux-musl
  arm64-darwin-24
  x86_64-linux
  x86_64-linux-gnu
  x86_64-linux-musl

DEPENDENCIES
  bootsnap
  brakeman
  capybara
  debug
  dry-operation
  hanami!
  hanami-controller (~> 2.2)
  hanami-view (~> 2.2)
  importmap-rails
  jbuilder
  kamal
  propshaft
  puma (>= 5.0)
  rails (~> 8.0.1)
  rspec-rails
  rubocop-rails-omakase
  selenium-webdriver
  solid_cable
  solid_cache
  solid_queue
  sqlite3 (>= 2.1)
  stimulus-rails
  thruster
  turbo-rails
  tzinfo-data
  web-console

BUNDLED WITH
   2.6.3

```

---

<div class="post-metadata">

**Author:** ![stephan](https://avatars.discourse-cdn.com/v4/letter/s/8baadc/32.png) [@stephan](https://discourse.hanakai.org/u/stephan)\
**Post date:** [February 17, 2025, 12:42am UTC](https://discourse.hanakai.org/t/rails-and-hanami-view-dont-get-along/1122/3 "2025-02-17T00:42:53Z")

</div>

Oops, I will update the original post. Yes, I see the teams list page working, but when you click “new team” it breaks with the error (for me) as described above.

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<div class="post-metadata">

**Author:** ![timriley](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.hanakai.org/timriley/32/621_2.png) [@timriley](https://discourse.hanakai.org/u/timriley)\
**Post date:** [February 17, 2025, 12:57am UTC](https://discourse.hanakai.org/t/rails-and-hanami-view-dont-get-along/1122/4 "2025-02-17T00:57:42Z")

</div>

I reckon you’ve found a conflict between Hanami::View’s `String` extension and Rails’ own.

In Hanami::View [we have the following extension](https://github.com/hanami/view/blob/77e6e0dcc4f8af6ca776acae18466ba0ce678425/lib/hanami/view/html.rb), which adds a single `#html_safe` method to `String`:

```auto
# Comments and spurious code removed so you can quickly get the gist.

module Hanami
  class View
    module HTML
      class SafeString < String
        # ...
      end

      module StringExtensions
        def html_safe
          Hanami::View::HTML::SafeString.new(self)
        end
      end
    end
  end
end

class String
  # Prepend our `#html_safe` method so that it takes precedence over Active Support's. When both
  # methods are loaded, the more likely scenario is that the user will want Hanami's, since in the
  # context of a Hanami app, Active Support is more likely to be loaded incidentally, as a
  # transitive dependency of another gem.
  #
  # Having our `#html_safe` available via this module also means that a user can also choose to
  # _undefine_ this method within the module if they'd rather use Active Support's.
  prepend Hanami::View::HTML::StringExtensions
end

```

What I think we’ve discovered here is that my assumption as stated in code comment above is incorrect. Here you’re intermingling Hanami with Rails, and you actually want _Rails’_ version of the string extensions. This makes sense, because Hanami’s extension provides only a subset of the functionality provided by Rails’ extension, and Rails needs all of it. Since we only care about `#html_safe`, I reckon Rails’ HTML-safe strings should still work fine within Hanami apps.

Fortunately for you, we did provide for a quick way to remove our string extensions. Whack this in an initializer or similar:

```ruby
Hanami::View::HTML::StringExtensions.undef_method(:html_safe)

```

This will ensure we don’t clobber Rails’ `String` extensions, and should hopefully get you past your errors.

Would you mind giving that a go, @stephan, and letting us know how you fare?

If this works for you, then I think we should change our `String` patching strategy in Hanami::View so we no longer “win” when there are conflicting patches.

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<div class="post-metadata">

**Author:** ![alassek](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.hanakai.org/alassek/32/532_2.png) [@alassek](https://discourse.hanakai.org/u/alassek)\
**Post date:** [February 17, 2025, 2:35am UTC](https://discourse.hanakai.org/t/rails-and-hanami-view-dont-get-along/1122/5 "2025-02-17T02:35:17Z")

</div>

We should probably treat presence of ActiveSupport and presence of Rails as different cases.

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<div class="post-metadata">

**Author:** ![alassek](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.hanakai.org/alassek/32/532_2.png) [@alassek](https://discourse.hanakai.org/u/alassek)\
**Post date:** [February 17, 2025, 2:48am UTC](https://discourse.hanakai.org/t/rails-and-hanami-view-dont-get-along/1122/6 "2025-02-17T02:48:12Z")

</div>

> [@timriley](#):
>
> `Hanami::View::HTML::StringExtensions.undef_method(:html_safe)`

This appears to clobber the method entirely. May need to gate this behavior before it gets prepended.

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<div class="post-metadata">

**Author:** ![timriley](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.hanakai.org/timriley/32/621_2.png) [@timriley](https://discourse.hanakai.org/u/timriley)\
**Post date:** [February 17, 2025, 2:49am UTC](https://discourse.hanakai.org/t/rails-and-hanami-view-dont-get-along/1122/7 "2025-02-17T02:49:59Z")

</div>

> [@alassek](#):
>
> This appears to clobber the method entirely. May need to gate this behavior before it gets prepended.

So there’s no `String#html_safe` _at all_ after running this? If so, not ideal!

This would be another workaround to use until we can make adjustments inside Hanami::View itself:

```ruby
Hanami::View::HTML::StringExtensions.class_eval do
  def html_safe
    ActiveSupport::SafeBuffer.new(self)
  end
end

```

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<div class="post-metadata">

**Author:** ![alassek](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.hanakai.org/alassek/32/532_2.png) [@alassek](https://discourse.hanakai.org/u/alassek)\
**Post date:** [February 17, 2025, 2:59am UTC](https://discourse.hanakai.org/t/rails-and-hanami-view-dont-get-along/1122/8 "2025-02-17T02:59:53Z")

</div>

This works for me!

 ![Screenshot 2025-02-16 at 8.59.18 PM](https://canada1.discourse-cdn.com/flex030/uploads/hanamirb/original/1X/2002ca45f4a948791024e0f4c5f1b98f9807599e.jpeg)

---

<div class="post-metadata">

**Author:** ![stephan](https://avatars.discourse-cdn.com/v4/letter/s/8baadc/32.png) [@stephan](https://discourse.hanakai.org/u/stephan)\
**Post date:** [February 17, 2025, 4:50am UTC](https://discourse.hanakai.org/t/rails-and-hanami-view-dont-get-along/1122/9 "2025-02-17T04:50:32Z")

</div>

I can also confirm that this works! Thank you both!

In my larger example I did find the connection to `rack` I suspected in the topic: The downgrading of `rack` and `rackup` due to the dependency of `hanami-controller` causes some system tests to fail with:

```auto
NoMethodError:
            undefined method `register' for Rackup::Handler:Module

```

This had been found previously ([System spec failures after upgrading to 1.0.1 · Issue #19 · rack/rackup · GitHub](https://github.com/rack/rackup/issues/19)), has a fix in puma ([https://github.com/puma/puma/pull/3532](https://github.com/puma/puma/pull/3532)) which was part of the 6.5.0 upgrade. After `bundle update` upgraded my puma from 6.4 to 6.6… things work!