refactor: defer Config loading — add explicit Config.load! method

Loading config.toml at module eval time (during require) runs before
the application's working directory is set, can slow down tests that
don't use config at all, and gives no way to reload between calls.

Move the load logic into Config.load! (mirrors the Options.parse! pattern
added in the previous commit). The module body now just initialises
@@config to {}.  Call Config.load! alongside Options.parse! at the top
of configure() so all entry points reload from the correct directory.

Also qualify File as ::File inside the RCM module to avoid resolving it
as RCM::File once the keyword files are loaded.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

2 files changed, 20 insertions, 8 deletions

diff --git a/lib/config.rb b/lib/config.rb
index 2a13ae0..fa43c4f 100644
--- a/lib/config.rb
+++ b/lib/config.rb
@@ -8,12 +8,23 @@ end
 module RCM
   # Configuration — config.toml is optional. If the toml gem is not installed
   # or no config.toml exists, config() will raise a helpful error when called.
+  #
+  # Config is not loaded at module load time. Call Config.load! once at the
+  # application entry point (e.g. from configure) before calling config().
+  # Tests that don't use config() don't need config.toml at all.
   module Config
-    @@config = if TOML_AVAILABLE && File.exist?('config.toml')
-                 TOML.load_file('config.toml')
-               else
-                 {}
-               end
+    @@config = {}
+
+    # Load (or reload) config.toml from the current working directory.
+    # Falls back to an empty hash when the toml gem is unavailable or the
+    # file does not exist, so callers that never invoke config() are unaffected.
+    def self.load!
+      @@config = if TOML_AVAILABLE && ::File.exist?('config.toml')
+                   TOML.load_file('config.toml')
+                 else
+                   {}
+                 end
+    end
 
     def config(key)
       raise "No such config key: #{key}" unless @@config.key?(key)
diff --git a/lib/dsl.rb b/lib/dsl.rb
index 6185c98..e3f6ee2 100644
--- a/lib/dsl.rb
+++ b/lib/dsl.rb
@@ -71,10 +71,11 @@ module RCM
 end
 
 def configure(reset: false, &block)
-  # Parse ARGV each time configure is called so that scripts which call
-  # configure multiple times (or test suites that reset state) always
-  # start with a fresh, consistent option set.
+  # Parse ARGV and load config.toml each time configure is called so that
+  # scripts and test suites that call configure multiple times always
+  # start from a consistent, freshly-loaded state.
   RCM::Options.parse!
+  RCM::Config.load!
   RCM::DSL.new(reset) do |rcm|
     rcm.info('Configuring...')
     rcm.instance_eval(&block)