Exclude legacy liquid-c from defaults

Author: tobi

CLAUDE.md

@@ -331,7 +331,7 @@ bundle exec rake generate
 ### Directory Structure
 
 - `bin/` - CLI executable
-- `examples/` - Example adapters (`liquid_ruby.rb`, `liquid_ruby_lax.rb`, `liquid_ruby_shopify.rb`, `json_rpc_ruby_liquid.rb`, `liquid_c.rb`, `liquid_c_strict.rb`, JIT variants)
+- `examples/` - Example adapters (`liquid_ruby.rb`, `liquid_ruby_lax.rb`, `liquid_ruby_shopify.rb`, `json_rpc_ruby_liquid.rb`, JIT variants); liquid-c examples are legacy explicit opt-ins and are excluded from defaults
 - `lib/liquid/spec/cli/` - CLI implementation
 - `specs/basics/` - Curated beginner ramp specs
 - `specs/liquid_ruby/` - Core Liquid specs from Shopify/liquid

Gemfile

@@ -12,12 +12,6 @@ else
   gem "liquid", github: "Shopify/liquid", tag: "v5.13.0"
 end
 
-# liquid-c is an optional C extension for performance. Only use if locally available.
-local_liquid_c_path = File.expand_path("../liquid-c", __dir__)
-if File.exist?(local_liquid_c_path)
-  gem "liquid-c", path: local_liquid_c_path, require: false
-end
-
 # Core test dependencies
 gem "minitest"
 gem "minitest-focus"

README.md

@@ -455,7 +455,7 @@ The `matrix` command runs specs across multiple adapters simultaneously and show
 liquid-spec tools matrix [options]
 
 Options:
-  --all                    Run all available adapters from examples/
+  --all                    Run all default adapters from examples/
   --adapters=LIST          Comma-separated list of adapters
   --reference=NAME         Reference adapter (default: liquid_ruby)
   -n, --name PATTERN       Filter specs by name pattern
@@ -465,14 +465,14 @@ Options:
   -v, --verbose            Show detailed output
 
 Examples:
-  # Compare all bundled adapters
+  # Compare the default bundled adapters
   liquid-spec tools matrix --all
 
   # Compare specific adapters
   liquid-spec tools matrix --adapters=liquid_ruby,liquid_ruby_lax
 
   # Compare adapters on specific tests
-  liquid-spec tools matrix --adapters=liquid_ruby,liquid_c -n truncate
+  liquid-spec tools matrix --adapters=liquid_ruby,my_adapter.rb -n truncate
 ```
 
 Output shows which adapters produce different results for each spec:
@@ -493,7 +493,7 @@ Adapters: liquid_ruby
 Output:
   "Hello w..."
 
-Adapters: liquid_c
+Adapters: my_adapter
 Output:
   "Hello wo..."
 ======================================================================
@@ -585,7 +585,7 @@ Use `liquid-spec bench --profile` to generate StackProf profiles for detailed pe
 liquid-spec bench examples/liquid_ruby.rb --profile
 
 # Multi-adapter profiling
-liquid-spec bench --adapters=liquid_ruby,liquid_c --profile
+liquid-spec bench --adapters=liquid_ruby,liquid_ruby_lax --profile
 ```
 
 A single-adapter profile directory contains four dumps:
@@ -639,7 +639,7 @@ Complexity: 20
 Saved to: /tmp/liquid-spec-2026-01-02.yml
 ```
 
-When using `--compare` (the default), the `expected` field can be omitted - it will be filled from the reference implementation. If your implementation differs from the reference, you'll see a prominent message encouraging you to contribute the spec.
+When using `--compare`, the `expected` field can be omitted—it will be filled from the reference implementation. If your implementation differs from the reference, you'll see a prominent message encouraging you to contribute the spec.
 
 Specs are automatically saved to `/tmp/liquid-spec-{date}.yml` for easy contribution back to liquid-spec.
 
@@ -684,7 +684,7 @@ See the `examples/` directory:
 - **`liquid_ruby_lax.rb`** - Shopify/liquid configured for lax-mode compatibility specs
 - **`liquid_ruby_shopify.rb`** - Shopify-flavored Liquid behavior
 - **`json_rpc_ruby_liquid.rb`** - JSON-RPC adapter backed by Shopify/liquid
-- **`liquid_c.rb`** / **`liquid_c_strict.rb`** - [liquid-c](https://github.com/Shopify/liquid-c) native extension examples
+- **`liquid_c.rb`** / **`liquid_c_strict.rb`** - Legacy, explicit opt-in liquid-c examples; excluded from default adapter runs
 - **`liquid_ruby_yjit.rb`** / **`liquid_ruby_zjit.rb`** - Ruby JIT benchmark variants
 
 ```bash

lib/liquid/spec/cli/bench.rb

@@ -10,7 +10,7 @@ module Spec
     module CLI
       # `liquid-spec bench` — run benchmarks sequentially with nice per-spec output.
       #
-      # - `liquid-spec bench`              → all builtin adapters, one after another
+      # - `liquid-spec bench`              → default builtin adapters, one after another
       # - `liquid-spec bench my_adapter.rb` → my_adapter vs liquid_ruby
       # - `liquid-spec bench my_adapter.rb -n storefront` → filtered
       #
@@ -22,7 +22,7 @@ module Bench
 
           Run benchmarks with hyperfine-style output.
 
-          With no adapter:    runs all builtin adapters sequentially
+          With no adapter:    runs default builtin adapters sequentially
           With an adapter:    runs ADAPTER vs liquid_ruby (reference)
 
           Comparisons that mix inline and JSON-RPC adapters emit a warning because
@@ -31,7 +31,7 @@ module Bench
           Options:
             -n, --name PATTERN    Filter specs by name pattern
             -s, --suite SUITE     Spec suite (default: benchmarks)
-            --all                 Run all builtin adapters
+            --all                 Run all default builtin adapters
             --adapter=PATH        Add a specific adapter
             --adapters=LIST       Comma-separated adapter list
             --profile             Write StackProf CPU/allocation profiles to /tmp
@@ -43,7 +43,7 @@ module Bench
             liquid-spec bench
             liquid-spec bench my_adapter.rb
             liquid-spec bench my_adapter.rb -n storefront
-            liquid-spec bench --adapters=liquid_ruby,liquid_c
+            liquid-spec bench --adapters=liquid_ruby,liquid_ruby_lax
         HELP
 
         class << self

lib/liquid/spec/cli/matrix.rb

@@ -20,7 +20,7 @@ module Matrix
 
           Options:
             -o, --output=DIR      Reports directory (default: $LIQUID_SPEC_REPORTS or #{Config::DEFAULT_REPORTS_DIR})
-            --all                 Run all available adapters from examples/
+            --all                 Run all default adapters from examples/
             --adapter=PATH        Add a local adapter (can be used multiple times)
             --adapters=LIST       Comma-separated list of adapters to run
             --reference=NAME      Reference adapter (default: liquid_ruby)
@@ -110,7 +110,7 @@ def run_matrix(options)
               $stderr.puts ""
               $stderr.puts "Usage:"
               $stderr.puts "  liquid-spec tools matrix --all"
-              $stderr.puts "  liquid-spec tools matrix --adapters=liquid_ruby,liquid_c"
+              $stderr.puts "  liquid-spec tools matrix --adapters=liquid_ruby,liquid_ruby_lax"
               $stderr.puts "  liquid-spec tools matrix --adapter=./my_adapter.rb"
               exit(1)
             end

lib/liquid/spec/cli/runs.rb

@@ -10,9 +10,17 @@ module CLI
       # whether adapters are builtin (from examples/) or local.
       class Runs
         Adapter = Struct.new(:name, :path, :builtin, :transport, keyword_init: true)
+        EXAMPLES_DIR = File.expand_path("../../../../examples", __dir__)
+        LEGACY_BUILTIN_ADAPTERS = %w[liquid_c liquid_c_strict].freeze
 
         attr_reader :adapters, :output_dir, :extra_specs
 
+        def self.default_builtin_adapter_paths
+          Dir[File.join(EXAMPLES_DIR, "*.rb")].sort.reject do |path|
+            LEGACY_BUILTIN_ADAPTERS.include?(File.basename(path, ".rb"))
+          end
+        end
+
         def initialize
           @adapters = []
           @extra_specs = []
@@ -74,9 +82,10 @@ def add_adapter(name_or_path)
           @adapters << resolved unless @adapters.any? { |a| a.path == resolved.path }
         end
 
-        # Add all builtin adapters from examples/
+        # Add the default builtin adapters. Legacy examples remain explicitly
+        # addressable by name/path, but are not part of no-argument or --all runs.
         def add_all_builtin_adapters
-          Dir[File.join(examples_dir, "*.rb")].sort.each do |path|
+          self.class.default_builtin_adapter_paths.each do |path|
             name = File.basename(path, ".rb")
             @adapters << Adapter.new(
               name: name,
@@ -202,7 +211,7 @@ def adapter_transport(path)
         end
 
         def examples_dir
-          @examples_dir ||= File.expand_path("../../../../examples", __dir__)
+          EXAMPLES_DIR
         end
       end
     end

lib/liquid/spec/cli/test.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require_relative "runs"
+
 module Liquid
   module Spec
     module CLI
@@ -8,16 +10,16 @@ module Test
         HELP = <<~HELP
           Usage: liquid-spec tools test [options]
 
-          Run specs against all available example adapters in the gem.
-          Automatically skips adapters whose dependencies are not installed.
+          Run specs against the default example adapters in the gem.
+          Legacy adapters remain available explicitly but are not run here.
 
           Options:
             -c, --compare         Compare adapter output against reference liquid-ruby
             -v, --verbose         Show verbose output
             -h, --help            Show this help
 
           Examples:
-            liquid-spec tools test                    # Run all available adapters
+            liquid-spec tools test                    # Run default example adapters
             liquid-spec tools test --compare          # Compare mode
             liquid-spec tools test -v                 # Verbose output
 
@@ -59,7 +61,7 @@ def self.run_all_adapters(options)
             exit(1)
           end
 
-          adapters = Dir[File.join(adapters_dir, "*.rb")]
+          adapters = Runs.default_builtin_adapter_paths
 
           if adapters.empty?
             $stderr.puts "No example adapters found in #{adapters_dir}"

test/runs_test.rb

@@ -6,6 +6,27 @@
 require "liquid/spec/cli/runs"
 
 class RunsTest < Minitest::Test
+  def test_default_builtin_adapters_exclude_legacy_liquid_c
+    paths = Liquid::Spec::CLI::Runs.default_builtin_adapter_paths
+    names = paths.map { |path| File.basename(path, ".rb") }
+
+    assert_includes names, "liquid_ruby"
+    assert_includes names, "json_rpc_ruby_liquid"
+    refute_includes names, "liquid_c"
+    refute_includes names, "liquid_c_strict"
+
+    runs = Liquid::Spec::CLI::Runs.new
+    runs.add_all_builtin_adapters
+    assert_equal names.sort, runs.adapter_names.sort
+  end
+
+  def test_legacy_liquid_c_adapter_remains_explicitly_addressable
+    runs = Liquid::Spec::CLI::Runs.new
+    runs.add_adapter("liquid_c")
+
+    assert_equal ["liquid_c"], runs.adapter_names
+  end
+
   def test_classifies_adapters_and_detects_mixed_benchmark_transports
     Dir.mktmpdir do |dir|
       inline_path = File.join(dir, "inline.rb")