Enforce exception message conventions with a separate lint bundle

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: dblock

.github/workflows/lint.yml

@@ -10,5 +10,7 @@ jobs:
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
+          ruby-version: '3.3'
+          bundler: latest
           bundler-cache: true
       - run: bundle exec rubocop

.rubocop.yml

@@ -5,6 +5,9 @@ require:
   - rubocop-rake
   - rubocop-rspec
 
+plugins:
+  - rubocop-exception_messages
+
 AllCops:
   TargetRubyVersion: 2.7
   NewCops: enable

.rubocop_todo.yml

@@ -6,6 +6,16 @@
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
+# Remaining offenses after safe autocorrection with modern RuboCop.
+Naming/PredicateMethod:
+  Exclude:
+    - 'lib/slack/events/request.rb'
+    - 'lib/slack/utils/security.rb'
+
+Style/DirectiveScope:
+  Exclude:
+    - 'lib/slack/utils/security.rb'
+
 # Offense count: 1
 # This cop supports unsafe auto-correction (--auto-correct-all).
 Lint/NonDeterministicRequireOrder:

AGENTS.md

@@ -0,0 +1,7 @@
+# Contributor guidance
+
+- Use the main Gemfile; lint dependencies are included only on Ruby 3.2+. Preserve the supported-Ruby test matrix and run RuboCop separately on Ruby 3.3 in CI.
+- Run `bundle exec rake` for tests and `bundle exec rubocop` for lint. When upgrading lint tooling, run `bundle exec rubocop -a` once, review corrections, and baseline only remaining unrelated offenses.
+- Exception message corrections can change public error strings. Update matching specs, including handwritten specs under `spec/slack/web/api/endpoints/custom/`.
+- Add a CHANGELOG entry under the next release with the pull request number and contributor attribution. Keep `Your contribution here`. After opening a PR, update the entry with its assigned number.
+- Generated endpoints and specs come from `bundle exec rake slack:api:update`. Persist endpoint changes in `lib/slack/web/api/patches/` and verify regeneration applies the patch. Do not edit the API-reference submodule or include existing submodule changes unless requested.

CHANGELOG.md

@@ -1,5 +1,6 @@
 ### 3.3.0 (Next)
 
+* [#603](https://github.com/slack-ruby/slack-ruby-client/pull/603): Enforce consistent exception messages with rubocop-exception_messages and run lint separately from the test matrix - [@dblock](https://github.com/dblock).
 * [#602](https://github.com/slack-ruby/slack-ruby-client/pull/602): Make gli an optional dependency; only the `slack` command-line client needs it - [@corsonknowles](https://github.com/corsonknowles).
 * [#591](https://github.com/slack-ruby/slack-ruby-client/pull/591): Generate AI CHANGELOG entries and PR summaries for automated API update PRs, lock simplecov below 1.1.0 to avoid breaking Coveralls - [@dblock](https://github.com/dblock).
 * [#590](https://github.com/slack-ruby/slack-ruby-client/pull/590): Add entity.acknowledgeCommentAction and entity.presentComments methods - [@slack-ruby-ci-bot](https://github.com/apps/slack-ruby-ci-bot).

CONTRIBUTING.md

@@ -59,7 +59,16 @@ We definitely appreciate pull requests that highlight or reproduce a problem, ev
 
 Implement your feature or bug fix.
 
-Ruby style is enforced with [Rubocop](https://github.com/bbatsov/rubocop). Run `bundle exec rubocop` and fix any style issues highlighted, auto-correct issues when possible with `bundle exec rubocop -a`. To silence generally ignored issues, including line lengths or code complexity metrics, run `bundle exec rubocop --auto-gen-config`.
+Ruby style is enforced with [RuboCop](https://github.com/rubocop/rubocop), including [exception message conventions](https://github.com/dblock/rubocop-exception_messages). The main Gemfile includes lint dependencies only on Ruby 3.2+ so tests can continue running on older supported Ruby versions.
+
+```bash
+bundle install
+bundle exec rubocop
+```
+
+Fix any style issues highlighted, auto-correcting safe issues with `bundle exec rubocop -a`. Exception message corrections require `-A`; review them and update message expectations in tests. To regenerate the baseline for generally ignored issues, including line lengths or code complexity metrics, run `bundle exec rubocop --auto-gen-config`.
+
+On Ruby 3.2+, `bundle exec rake rubocop` also runs lint. The default `bundle exec rake` runs tests only; CI runs lint separately on Ruby 3.3.
 
 Make sure that `bundle exec rake` completes without errors.
 

Gemfile

@@ -18,10 +18,6 @@ group :test do
   gem 'racc'
   gem 'rake', '~> 13'
   gem 'rspec'
-  gem 'rubocop', '1.26.1' # Lock to specific version to avoid breaking cops/changes
-  gem 'rubocop-performance'
-  gem 'rubocop-rake'
-  gem 'rubocop-rspec'
   # Lock below 1.1.0, which started writing float timestamps to
   # coverage/.resultset.json, breaking coverallsapp/github-action's parser
   # (coverallsapp/github-action#269, coverallsapp/coverage-reporter#191).
@@ -31,3 +27,13 @@ group :test do
   gem 'vcr'
   gem 'webmock'
 end
+
+if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('3.2')
+  group :lint do
+    gem 'rubocop', '~> 1.72'
+    gem 'rubocop-exception_messages', '~> 0.2.0', require: false
+    gem 'rubocop-performance', '1.19.1'
+    gem 'rubocop-rake', '0.6.0'
+    gem 'rubocop-rspec', '2.11.1'
+  end
+end

Rakefile

@@ -12,10 +12,14 @@ RSpec::Core::RakeTask.new(:spec) do |spec|
   spec.pattern = FileList['spec/**/*_spec.rb']
 end
 
-require 'rubocop/rake_task'
-RuboCop::RakeTask.new
+desc 'Run RuboCop (Ruby 3.2+).'
+task :rubocop do
+  abort 'RuboCop requires Ruby 3.2 or newer' if Gem::Version.new(RUBY_VERSION) < Gem::Version.new('3.2')
 
-task default: %i[spec rubocop]
+  sh 'bundle exec rubocop'
+end
+
+task default: :spec
 
 load 'tasks/git.rake'
 load 'tasks/web.rake'

examples/files_upload_v2/files_upload_v2.rb

@@ -3,7 +3,7 @@
 require 'securerandom'
 
 Slack.configure do |config|
-  config.token = ENV['SLACK_API_TOKEN']
+  config.token = ENV.fetch('SLACK_API_TOKEN', nil)
   raise 'Missing ENV[SLACK_API_TOKEN]!' unless config.token
 end
 

examples/hi_web/hi.rb

@@ -2,7 +2,7 @@
 require 'slack-ruby-client'
 
 Slack.configure do |config|
-  config.token = ENV['SLACK_API_TOKEN']
+  config.token = ENV.fetch('SLACK_API_TOKEN', nil)
   raise 'Missing ENV[SLACK_API_TOKEN]!' unless config.token
 end