Fixed error with dup and clone

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## 0.3.0 (unreleased)
 
+- Fixed error with `dup` and `clone`
 - Dropped support for Ruby < 3
 
 ## 0.2.7 (2023-02-01)

lib/lightgbm/booster.rb

@@ -14,7 +14,7 @@ def initialize(params: nil, train_set: nil, model_file: nil, model_str: nil)
         set_verbosity(params)
         check_result FFI.LGBM_BoosterCreate(train_set.handle_pointer, params_str(params), @handle)
       end
-      ObjectSpace.define_finalizer(self, self.class.finalize(handle_pointer))
+      ObjectSpace.define_finalizer(@handle, self.class.finalize(handle_pointer.to_i))
 
       self.best_iteration = -1
 
@@ -179,9 +179,9 @@ def update
       finished.read_int == 1
     end
 
-    def self.finalize(pointer)
+    def self.finalize(addr)
       # must use proc instead of stabby lambda
-      proc { FFI.LGBM_BoosterFree(pointer) }
+      proc { FFI.LGBM_BoosterFree(::FFI::Pointer.new(:pointer, addr)) }
     end
 
     private

lib/lightgbm/dataset.rb

@@ -75,7 +75,6 @@ def feature_names=(feature_names)
     def reference=(reference)
       if reference != @reference
         @reference = reference
-        free_handle
         construct
       end
     end
@@ -110,9 +109,9 @@ def handle_pointer
       @handle.read_pointer
     end
 
-    def self.finalize(pointer)
+    def self.finalize(addr)
       # must use proc instead of stabby lambda
-      proc { FFI.LGBM_DatasetFree(pointer) }
+      proc { FFI.LGBM_DatasetFree(::FFI::Pointer.new(:pointer, addr)) }
     end
 
     private
@@ -164,19 +163,14 @@ def construct
 
         check_result FFI.LGBM_DatasetCreateFromMat(c_data, 1, nrow, ncol, 1, parameters, reference, @handle)
       end
-      ObjectSpace.define_finalizer(self, self.class.finalize(handle_pointer)) unless used_indices
+      ObjectSpace.define_finalizer(@handle, self.class.finalize(handle_pointer.to_i)) unless used_indices
 
       self.label = @label if @label
       self.weight = @weight if @weight
       self.group = @group if @group
       self.feature_names = @feature_names if @feature_names
     end
 
-    def free_handle
-      FFI.LGBM_DatasetFree(handle_pointer)
-      ObjectSpace.undefine_finalizer(self)
-    end
-
     def dump_text(filename)
       check_result FFI.LGBM_DatasetDumpText(handle_pointer, filename)
     end

test/booster_test.rb

@@ -54,6 +54,11 @@ def test_num_trees
     assert_equal 100, booster.num_trees
   end
 
+  def test_copy
+    booster.dup
+    booster.clone
+  end
+
   private
 
   def booster

test/dataset_test.rb

@@ -79,4 +79,9 @@ def test_rover
     label = data.delete("y")
     LightGBM::Dataset.new(data, label: label)
   end
+
+  def test_copy
+    regression_train.dup
+    regression_train.clone
+  end
 end