Use same dupped binding while same sub-session

This is another fix of #424.
Tests are imported from #424 written by @st0012.

Author: ko1

ext/debug/debug.c

@@ -32,7 +32,10 @@ di_entry(VALUE loc, VALUE self, VALUE binding, VALUE iseq, VALUE klass, VALUE de
                          // :show_line, :local_variables
                          Qnil,
                          // :_local_variables, :_callee # for recorder
-                         Qnil, Qnil);
+                         Qnil, Qnil,
+                         // :dupped_binding
+                         Qnil
+                         );
 }
 
 static int

lib/debug/frame_info.rb

@@ -5,7 +5,8 @@ module DEBUGGER__
                           :has_return_value,     :return_value,
                           :has_raised_exception, :raised_exception,
                           :show_line,
-                          :_local_variables, :_callee # for recorder
+                          :_local_variables, :_callee, # for recorder
+                          :dupped_binding,
                         )
 
   # extend FrameInfo with debug.so
@@ -118,19 +119,13 @@ def location_str
       "#{pretty_path}:#{location.lineno}"
     end
 
-    private def make_binding
-      __newb__ = self.self.instance_eval('binding')
-      self.local_variables.each{|var, val|
-        __newb__.local_variable_set(var, val)
-      }
-      __newb__
-    end
-
     def eval_binding
-      if b = self.binding
+      if b = self.dupped_binding
         b
-      elsif self.local_variables
-        make_binding
+      else
+        b = TOPLEVEL_BINDING unless b = self.binding
+        b = self.binding || TOPLEVEL_BINDING
+        self.dupped_binding = b.dup
       end
     end
 

lib/debug/thread_client.rb

@@ -352,8 +352,7 @@ def instance_eval_for_cmethod frame_self, src
     def frame_eval src, re_raise: false
       @success_last_eval = false
 
-      b = current_frame&.eval_binding || TOPLEVEL_BINDING
-      b = b.dup
+      b = current_frame.eval_binding
 
       special_local_variables current_frame do |name, var|
         b.local_variable_set(name, var) if /\%/ !~ name
@@ -445,7 +444,7 @@ def current_frame
     def special_local_variables frame
       SPECIAL_LOCAL_VARS.each do |mid, name|
         next unless frame&.send("has_#{mid}")
-        name = name.sub('_', '%') if frame.binding.local_variable_defined? name
+        name = name.sub('_', '%') if frame.eval_binding.local_variable_defined?(name)
         yield name, frame.send(mid)
       end
     end
@@ -653,7 +652,7 @@ def make_breakpoint args
       case args.first
       when :method
         klass_name, op, method_name, cond, cmd, path = args[1..]
-        bp = MethodBreakpoint.new(current_frame.binding, klass_name, op, method_name, cond: cond, command: cmd, path: path)
+        bp = MethodBreakpoint.new(current_frame.eval_binding, klass_name, op, method_name, cond: cond, command: cmd, path: path)
         begin
           bp.enable
         rescue Exception => e

test/debug/debugger_local_test.rb

@@ -4,84 +4,160 @@
 
 module DEBUGGER__
   class DebuggerLocalsTest < TestCase
-    class RaisedTest < TestCase
+    class REPLLocalsTest < TestCase
       def program
         <<~RUBY
-     1| _rescued_ = 1111
-     2| foo rescue nil
-     3|
-     4| # check repl variable doesn't leak to the program
-     5| result = _rescued_ * 2
-     6| binding.b
+        1| a = 1
         RUBY
       end
 
-      def test_raised_is_accessible_from_repl
+      def test_locals_added_in_locals_are_accessible_between_evaluations
         debug_code(program) do
-          type "catch Exception"
-          type "c"
-          type "_raised"
-          assert_line_text(/#<NameError: undefined local variable or method `foo' for main:Object/)
-          type "c"
-          type "result"
-          assert_line_text(/2222/)
+          type "y = 50"
+          type "y"
+          assert_line_text(/50/)
           type "c"
         end
       end
+    end
 
-      def test_raised_is_accessible_from_command
-        debug_code(program) do
-          type "catch Exception pre: p _raised"
-          type "c"
-          assert_line_text(/#<NameError: undefined local variable or method `foo' for main:Object/)
-          type "c"
-          type "result"
-          assert_line_text(/2222/)
-          type "c"
+    class RaisedTest < TestCase
+      class RubyMethodTest < TestCase
+        def program
+          <<~RUBY
+       1| foo rescue nil
+          RUBY
+        end
+
+        def test_raised_is_accessible_from_repl
+          debug_code(program) do
+            type "catch Exception"
+            type "c"
+            type "_raised"
+            assert_line_text(/#<NameError: undefined local variable or method `foo' for main:Object/)
+            type "c"
+          end
+        end
+
+        def test_raised_is_accessible_from_command
+          debug_code(program) do
+            type "catch Exception pre: p _raised"
+            type "c"
+            assert_line_text(/#<NameError: undefined local variable or method `foo' for main:Object/)
+            type "c"
+          end
+        end
+      end
+
+      class CMethodTest < TestCase
+        def program
+          <<~RUBY
+       1| 1/0 rescue nil
+          RUBY
+        end
+
+        def test_raised_is_accessible_from_repl
+          debug_code(program) do
+            type "catch Exception"
+            type "c"
+            type "_raised"
+            assert_line_text(/ZeroDivisionError/)
+            type "c"
+          end
+        end
+
+        def test_raised_is_accessible_from_command
+          debug_code(program) do
+            type "catch Exception pre: p _raised"
+            type "c"
+            assert_line_text(/ZeroDivisionError/)
+            type "c"
+          end
+        end
+      end
+
+      class EncapsulationTest < TestCase
+        def program
+          <<~RUBY
+         1| 1/0 rescue nil
+         2| a = _raised
+          RUBY
+        end
+
+        def test_raised_doesnt_leak_to_program_binding
+          debug_code(program) do
+            type "catch StandardError"
+            type "c"
+            # stops for ZeroDivisionError
+            type "info"
+            type "_raised"
+            assert_line_text(/ZeroDivisionError/)
+            type "c"
+
+            # stops for NoMethodError because _raised is not defiend in the program
+            type "_raised"
+            assert_line_text(/NameError: undefined local variable or method `_raised' for main:Object/)
+            type "c"
+          end
         end
       end
     end
 
     class ReturnedTest < TestCase
       def program
         <<~RUBY
-   1| _return = 1111
-   2|
-   3| def foo
-   4|   "foo"
-   5| end
-   6|
-   7| foo
-   8|
-   9| # check repl variable doesn't leak to the program
-  10| result = _return * 2
-  11|
-  12| binding.b
+   1| def foo
+   2|   "foo"
+   3| end
+   4|
+   5| foo
         RUBY
       end
 
       def test_returned_is_accessible_from_repl
         debug_code(program) do
-          type "b 5"
+          type "b 3"
           type "c"
           type "_return + 'bar'"
           assert_line_text(/"foobar"/)
           type "c"
-          type "result"
-          assert_line_text(/2222/)
-          type "q!"
         end
       end
 
       def test_returned_is_accessible_from_command
         debug_code(program) do
-          type "b 5 pre: p _return + 'bar'"
+          type "b 3 pre: p _return + 'bar'"
           type "c"
           assert_line_text(/"foobar"/)
           type "c"
-          type "result"
-          assert_line_text(/2222/)
-          type "q!"
+        end
+      end
+
+      class EncapsulationTest < TestCase
+        def program
+          <<~RUBY
+         1| def foo
+         2|   "foo"
+         3| end
+         4|
+         5| foo
+         6| puts _return
+          RUBY
+        end
+
+        def test_raised_doesnt_leak_to_program_binding
+          debug_code(program) do
+            type "catch StandardError"
+            type "b 3"
+            type "c"
+            type "_return + 'bar'"
+            assert_line_text(/"foobar"/)
+            type "c"
+            # stops for NoMethodError because _return is not defiend in the program
+            type "_raised"
+            assert_line_text(/NameError: undefined local variable or method `_return' for main:Object/)
+            type "c"
+          end
         end
       end
     end