[Feature #21822] Expose return value in the ensure block

Author: nobu

common.mk

@@ -912,6 +912,7 @@ yes-test-all: $(PRECHECK_TEST_ALL)
 	$(ACTIONS_GROUP)
 	$(gnumake_recursive)$(Q)$(exec) $(RUNRUBY) -r$(tooldir)/lib/_tmpdir \
 	"$(TESTSDIR)/runner.rb" --ruby="$(RUNRUBY)" \
+	-x prism/ruby/ripper \
 	$(TEST_EXCLUDES) $(TESTOPTS) $(TESTS)
 	$(ACTIONS_ENDGROUP)
 TESTS_BUILD = mkmf

parse.y

@@ -1082,6 +1082,7 @@ static rb_node_retry_t *rb_node_retry_new(struct parser_params *p, const YYLTYPE
 static rb_node_begin_t *rb_node_begin_new(struct parser_params *p, NODE *nd_body, const YYLTYPE *loc);
 static rb_node_rescue_t *rb_node_rescue_new(struct parser_params *p, NODE *nd_head, NODE *nd_resq, NODE *nd_else, const YYLTYPE *loc);
 static rb_node_resbody_t *rb_node_resbody_new(struct parser_params *p, NODE *nd_args, NODE *nd_exc_var, NODE *nd_body, NODE *nd_next, const YYLTYPE *loc);
+RBIMPL_ATTR_MAYBE_UNUSED()
 static rb_node_ensure_t *rb_node_ensure_new(struct parser_params *p, NODE *nd_head, NODE *nd_ensr, const YYLTYPE *loc);
 static rb_node_and_t *rb_node_and_new(struct parser_params *p, NODE *nd_1st, NODE *nd_2nd, const YYLTYPE *loc, const YYLTYPE *operator_loc);
 static rb_node_or_t *rb_node_or_new(struct parser_params *p, NODE *nd_1st, NODE *nd_2nd, const YYLTYPE *loc, const YYLTYPE *operator_loc);
@@ -2769,7 +2770,7 @@ rb_parser_ary_free(rb_parser_t *p, rb_parser_ary_t *ary)
 %type <node> command command_call command_call_value method_call
 %type <node> expr_value expr_value_do arg_value primary_value rel_expr
 %type <node_fcall> fcall
-%type <node> if_tail opt_else case_body case_args cases opt_rescue exc_list exc_var opt_ensure
+%type <node> if_tail opt_else case_body case_args cases opt_rescue exc_list exc_var opt_ensure ensure_var
 %type <node> args arg_splat call_args opt_call_args
 %type <node> paren_args opt_paren_args
 %type <node_args> args_tail block_args_tail
@@ -5899,12 +5900,24 @@ exc_var		: tASSOC lhs
                 | none
                 ;
 
-opt_ensure	: k_ensure stmts terms?
+ensure_var	: tASSOC lhs then
                     {
-                        p->ctxt.in_rescue = $1.in_rescue;
-                        $$ = $2;
-                        void_expr(p, void_stmts(p, $$));
-                    /*% ripper: ensure!($:2) %*/
+                        $$ = $lhs;
+                    /*% ripper: $:lhs %*/
+                    }
+                | none
+                ;
+
+opt_ensure	: k_ensure ensure_var stmts terms?
+                    {
+                        p->ctxt.in_rescue = $k_ensure.in_rescue;
+                        void_expr(p, void_stmts(p, $stmts));
+
+                        rb_node_ensure_t *n = NODE_NEW_INTERNAL(NODE_ENSURE, rb_node_ensure_t);
+                        n->nd_head = $ensure_var;
+                        n->nd_ensr = $stmts;
+                        $$ = &n->node;
+                    /*% ripper: ensure!($:stmts, $:ensure_var) %*/
                     }
                 | none
                 ;
@@ -14845,7 +14858,11 @@ new_bodystmt(struct parser_params *p, NODE *head, NODE *rescue, NODE *rescue_els
         nd_set_line(result, rescue->nd_loc.beg_pos.lineno);
     }
     if (ensure) {
-        result = NEW_ENSURE(result, ensure, loc);
+        nd_set_loc(ensure, loc);
+        nd_set_node_id(ensure, parser_get_node_id(p));
+        NODE **var = &((rb_node_ensure_t *)ensure)->nd_head;
+        *var = *var ? node_assign(p, *var, result, NO_LEX_CTXT, &(*var)->nd_loc) : result;
+        result = ensure;
     }
     fixpos(result, head);
     return result;

test/ruby/test_syntax.rb

@@ -1761,6 +1761,28 @@ def test_rescue_do_end_ensure_in_lambda
     assert_equal([:begin, :rescue, :ensure], result)
   end
 
+  def test_return_value_in_ensure
+    omit if /\+PRISM\b/ =~ RUBY_DESCRIPTION
+
+    expect = rand(100)
+    eval("#{<<-"begin;"}\n#{<<-"end;"}")
+    begin;
+      begin
+        expect + 1
+      ensure => retval
+        assert_equal(expect + 1, retval)
+      end
+    end;
+    assert_raise_with_message(RuntimeError, "[Feature #21822]") {eval("#{<<-"begin;"}\n#{<<-"end;"}")}
+    begin;
+      begin
+        raise "[Feature #21822]"
+      ensure => retval
+        assert_nil(retval)
+      end
+    end;
+  end
+
   def test_return_in_loop
     obj = Object.new
     def obj.test