Module: GeneratorMessages::PackageManagerDetection

Included in:
GeneratorMessages
Defined in:
lib/generators/react_on_rails/generator_messages/package_manager_detection.rb

Overview

Package-manager detection helpers used by the install generator and the post-install message. Split out of GeneratorMessages to keep that class under Metrics/ClassLength and to group related logic together.

Constant Summary collapse

SUPPORTED_PACKAGE_MANAGERS = 
%w[npm pnpm yarn bun].freeze
LOCKFILE_CANDIDATES_BY_MANAGER =

Hash insertion order is the detection priority used by detect_package_manager_from_lockfiles (yarn → pnpm → bun → npm).

{
  "yarn" => ["yarn.lock"],
  "pnpm" => ["pnpm-lock.yaml"],
  "bun" => ["bun.lock", "bun.lockb"],
  "npm" => ["package-lock.json"]
}.freeze

Instance Method Summary collapse

Instance Method Details

#detect_package_manager(app_root: Dir.pwd, package_json: PACKAGE_JSON_UNSET) ⇒ Object

Detects the package manager in priority order:

  1. REACT_ON_RAILS_PACKAGE_MANAGER env variable
  2. packageManager field in package.json (Corepack standard)
  3. Lockfile on disk
  4. Falls back to "npm" (Shakapacker 8.x default)

Pass app_root: to resolve paths against a specific directory (e.g. destination_root in generators) instead of Dir.pwd. Omit package_json: (the default) to read package.json from disk. Pass package_json: <parsed_hash> to reuse an already-parsed package.json and avoid a re-read (callers that also inspect scripts/deps should parse once and pass the hash). Pass package_json: nil when the caller already attempted to read package.json and wants detection to fall through directly to lockfile heuristics.



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# File 'lib/generators/react_on_rails/generator_messages/package_manager_detection.rb', line 38

def detect_package_manager(app_root: Dir.pwd, package_json: PACKAGE_JSON_UNSET)
  detect_package_manager_with_source(
    app_root:,
    package_json:
  ).first
end

#detect_package_manager_from_lockfiles(app_root: Dir.pwd) ⇒ Object 



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# File 'lib/generators/react_on_rails/generator_messages/package_manager_detection.rb', line 105

def detect_package_manager_from_lockfiles(app_root: Dir.pwd)
  LOCKFILE_CANDIDATES_BY_MANAGER.keys.find do |pm|
    lockfile_for_manager?(pm, app_root:)
  end
end

#detect_package_manager_with_source(app_root: Dir.pwd, package_json: PACKAGE_JSON_UNSET) ⇒ Object

source is one of :env, :package_json, :lockfile, :default — used to name the originating source when surfacing detection errors.

See detect_package_manager for the package_json: three-way semantics (omitted = read from disk, nil = caller cached absent, Hash = pre-parsed).



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# File 'lib/generators/react_on_rails/generator_messages/package_manager_detection.rb', line 50

def detect_package_manager_with_source(app_root: Dir.pwd, package_json: PACKAGE_JSON_UNSET)
  env_package_manager = ENV.fetch("REACT_ON_RAILS_PACKAGE_MANAGER", nil)&.strip&.downcase
  return [env_package_manager, :env] if supported_package_manager?(env_package_manager)

  content = package_json_content(
    app_root:,
    package_json:
  )
  pm_from_json = content ? package_manager_name_from_content(content) : nil
  return [pm_from_json, :package_json] if pm_from_json

  pm_from_lockfile = detect_package_manager_from_lockfiles(app_root:)
  return [pm_from_lockfile, :lockfile] if pm_from_lockfile

  ["npm", :default]
end

#lockfile_filename_for(package_manager, app_root: Dir.pwd) ⇒ Object 



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# File 'lib/generators/react_on_rails/generator_messages/package_manager_detection.rb', line 67

def lockfile_filename_for(package_manager, app_root: Dir.pwd)
  LOCKFILE_CANDIDATES_BY_MANAGER[package_manager]&.find do |name|
    File.exist?(File.join(app_root, name))
  end
end

#lockfile_for_manager?(package_manager, app_root: Dir.pwd) ⇒ Boolean

Used by the CI scaffold so cache: / <pm> install never reference a lockfile that's not on disk (e.g. packageManager: pnpm without pnpm-lock.yaml, which breaks actions/setup-node's cache step).

Returns:

  • (Boolean) 


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# File 'lib/generators/react_on_rails/generator_messages/package_manager_detection.rb', line 101

def lockfile_for_manager?(package_manager, app_root: Dir.pwd)
  !lockfile_filename_for(package_manager, app_root:).nil?
end

#package_manager_declared?(manager:, app_root: Dir.pwd, package_json: PACKAGE_JSON_UNSET) ⇒ Boolean

Returns true when package.json declares a top-level packageManager field with an npm-style version/range/tag (e.g. "pnpm@9.0.0", "pnpm@^10.0.0", or "pnpm@latest") for the requested manager. The CI scaffold treats these as declared so it does not inject a conflicting fallback version:. Projects that need reproducible Corepack behavior should prefer an exact version, optionally with a hash (e.g. "pnpm@9.0.0+sha256.abc"). A bare name without @<version> returns false because pnpm/action-setup has no version to resolve from it. Used by the CI scaffold to decide whether pnpm/action-setup needs an explicit version: key; exact SemVer validation belongs only where a caller needs to extract a reproducible version pin. Pass package_json: <parsed_hash> to reuse an already-parsed package.json and package_json: nil to preserve a cached missing/unreadable read.

Returns:

  • (Boolean) 


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# File 'lib/generators/react_on_rails/generator_messages/package_manager_detection.rb', line 85

def package_manager_declared?(manager:, app_root: Dir.pwd, package_json: PACKAGE_JSON_UNSET)
  content = package_json_content(
    app_root:,
    package_json:
  )
  return false unless content

  declared = versioned_package_manager_name_from_content(content)
  return false if declared.nil?

  declared == manager.to_s.downcase
end

#package_manager_executable_available?(package_manager) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/generators/react_on_rails/generator_messages/package_manager_detection.rb', line 115

def package_manager_executable_available?(package_manager)
  return false unless supported_package_manager?(package_manager)

  ReactOnRails::Utils.command_available?(package_manager)
end

#read_package_json(app_root) ⇒ Object

Parses package.json once and returns the hash, or nil if the file is missing or unreadable. Generator code can reuse the same parsed hash across setup, template, and message paths.

Intentionally public: install_generator and other generator callers read package.json once and pass the result to detect_package_manager / package_manager_declared? to avoid repeated disk reads. When this returns nil, pass package_json: nil to those helpers to preserve that cached missing/unreadable state.



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# File 'lib/generators/react_on_rails/generator_messages/package_manager_detection.rb', line 132

def read_package_json(app_root)
  package_json_path = File.join(app_root, "package.json")
  return nil unless File.exist?(package_json_path)

  JSON.parse(File.read(package_json_path))
rescue JSON::ParserError, Errno::EACCES, Errno::ENOENT
  nil
end

#supported_package_manager?(package_manager) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/generators/react_on_rails/generator_messages/package_manager_detection.rb', line 111

def supported_package_manager?(package_manager)
  SUPPORTED_PACKAGE_MANAGERS.include?(package_manager)
end