Add support for SQLite

Rails 8 ships with production-grade SQLite, which means
active_record_doctor should support it, too. This commit adds a test
suite for SQLite3. This required making a few changes:

1. Making the database name used by the test suite depend on the adapter
   as SQLite uses an in-memory database.
2. Dedicated require_* methods for skipping test cases that are relevant
   to the current database under test.
3. Splitting a few test cases into SQLite-specific code and code for
   other databases.
4. Not testing against Ruby 3.0 as the SQLite gem requires 3.1.
5. Adding a GitHub Actions workflow for SQLite.

Additionally, short_primary_key is effectively disabled in SQLite.

Author: gregnavis

.github/workflows/mysql.yml

@@ -63,11 +63,8 @@ jobs:
           - 3306:3306
     strategy:
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3"]
+        ruby: ["3.1", "3.2", "3.3"]
         active_record: ["7.0", "7.1", "7.2"]
-        exclude:
-          - ruby: "3.0"
-            active_record: "7.2"
     env:
       BUNDLE_GEMFILE: ${{ github.workspace }}/gemfiles/Gemfile.activerecord-${{ matrix.active_record }}.x
     steps:

.github/workflows/postgresql.yml

@@ -63,11 +63,8 @@ jobs:
           - 5432:5432
     strategy:
       matrix:
-        ruby: ["3.0", "3.1", "3.2", "3.3"]
+        ruby: ["3.1", "3.2", "3.3"]
         active_record: ["7.0", "7.1", "7.2"]
-        exclude:
-          - ruby: "3.0"
-            active_record: "7.2"
     env:
       BUNDLE_GEMFILE: ${{ github.workspace }}/gemfiles/Gemfile.activerecord-${{ matrix.active_record }}.x
     steps:

.github/workflows/sqlite.yml

@@ -0,0 +1,37 @@
+name: Test SQLite
+on: [push, pull_request]
+
+jobs:
+  test-latest:
+    name: "Active Record 8.0 + Ruby 3.3"
+    runs-on: ubuntu-latest
+    env:
+      BUNDLE_GEMFILE: ${{ github.workspace }}/gemfiles/Gemfile.activerecord-8.0.x
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: "3.3"
+          bundler-cache: true
+      - name: Run the test suite against SQLite
+        run: bundle exec rake test:sqlite3
+
+  test-supported:
+    name: "Active Record ${{ matrix.active_record }} + Ruby ${{ matrix.ruby }}"
+    needs: [test-latest]
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby: ["3.1", "3.2", "3.3"]
+        active_record: ["7.0", "7.1", "7.2"]
+    env:
+      BUNDLE_GEMFILE: ${{ github.workspace }}/gemfiles/Gemfile.activerecord-${{ matrix.active_record }}.x
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          rubygems: ${{ matrix.rubygems }}
+          bundler-cache: true
+      - name: Run the test suite against SQLite
+        run: bundle exec rake test:sqlite3

Rakefile

@@ -24,9 +24,9 @@ RuboCop::RakeTask.new
 require "rake/testtask"
 
 namespace :test do
-  ["postgresql", "mysql2"].each do |adapter|
+  ["postgresql", "mysql2", "sqlite3"].each do |adapter|
     Rake::TestTask.new(adapter) do |t|
-      t.deps = ["set_#{adapter}_env"]
+      t.deps = ["prepare_#{adapter}"]
       t.libs = ["lib", "test"]
       t.ruby_opts = ["-rsetup"]
       t.pattern = "test/**/*_test.rb"
@@ -36,10 +36,12 @@ namespace :test do
       t.warning = false
     end
 
-    task("set_#{adapter}_env") { ENV["DATABASE_ADAPTER"] = adapter }
+    task :"prepare_#{adapter}" do
+      ENV["DATABASE_ADAPTER"] = adapter
+    end
   end
 end
 
-task test: ["test:postgresql", "test:mysql2"]
+task test: ["test:postgresql", "test:mysql2", "test:sqlite3"]
 
 task default: :test

active_record_doctor.gemspec

@@ -28,5 +28,6 @@ Gem::Specification.new do |s|
   s.add_development_dependency "railties", ACTIVE_RECORD_SPEC
   s.add_development_dependency "rake", "~> 13.2.1"
   s.add_development_dependency "rubocop", "~> 1.68.0"
+  s.add_development_dependency "sqlite3", "~> 2.2.0"
   s.add_development_dependency "transient_record", "~> 2.0.0"
 end

gemfiles/Gemfile.activerecord-7.0.x

@@ -4,3 +4,4 @@ gemspec path: File.join(File.dirname(__FILE__), "..")
 gem "activerecord", "~> 7.0.0"
 gem "pg", "~> 1.5.9"
 gem "mysql2", "~> 0.5.6"
+gem "sqlite3", "~> 1.4"

gemfiles/Gemfile.activerecord-7.1.x

@@ -4,3 +4,4 @@ gemspec path: File.join(File.dirname(__FILE__), "..")
 gem "activerecord", "~> 7.1.0"
 gem "pg", "~> 1.5.9"
 gem "mysql2", "~> 0.5.6"
+gem "sqlite3", "~> 1.4"

gemfiles/Gemfile.activerecord-7.2.x

@@ -4,3 +4,4 @@ gemspec path: File.join(File.dirname(__FILE__), "..")
 gem "activerecord", "~> 7.2.0"
 gem "pg", "~> 1.5.9"
 gem "mysql2", "~> 0.5.6"
+gem "sqlite3", "~> 1.4"

lib/active_record_doctor/detectors/short_primary_key_type.rb

@@ -20,6 +20,8 @@ def message(table:, column:)
       end
 
       def detect
+        return if ActiveRecordDoctor::Utils.sqlite?
+
         each_table(except: config(:ignore_tables)) do |table|
           column = primary_key(table)
           next if column.nil?

lib/active_record_doctor/utils.rb

@@ -11,9 +11,14 @@ def mysql?(connection = ActiveRecord::Base.connection)
         connection.adapter_name == "Mysql2"
       end
 
+      def sqlite?(connection = ActiveRecord::Base.connection)
+        connection.adapter_name == "SQLite"
+      end
+
       def expression_indexes_unsupported?(connection = ActiveRecord::Base.connection)
-        # Active Record is unable to correctly parse expression indexes for MySQL.
-        mysql?(connection) && ActiveRecord::VERSION::STRING < "7.1"
+        sqlite?(connection) ||
+          # Active Record is unable to correctly parse expression indexes for MySQL.
+          (mysql?(connection) && ActiveRecord::VERSION::STRING < "7.1")
       end
     end
   end