Only require pstore if needed

Author: orien

Gemfile

@@ -29,7 +29,7 @@ if RUBY_VERSION >= '3.4'
 end
 
 if RUBY_VERSION >= '4.0'
-  gem 'pstore'
   gem 'logger'
   gem 'ostruct'
+  gem 'pstore'
 end

lib/webmachine/trace/pstore_trace_store.rb

@@ -1,16 +1,15 @@
-require 'pstore'
-
 module Webmachine
   module Trace
-    # Implements a trace storage using PStore from Ruby's standard
-    # library. To use this trace store, specify the :pstore engine
-    # and a path where it can store traces:
+    # Implements a trace storage using the pstore gem. To use this trace store,
+    # add `pstore` to your Gemfile and specify the :pstore engine and a path
+    # where it can store traces:
     # @example
     #   Webmachine::Trace.trace_store = :pstore, "/tmp/webmachine.trace"
     class PStoreTraceStore
       # @api private
       # @param [String] path where to store traces in a PStore
       def initialize(path)
+        require 'pstore' # JIT load of the pstore gem. Avoid requiring the dependency when this class is not used.
         @pstore = PStore.new(path)
       end