[Bug #20978] Stringize Fiber storage keys

Merged: https://github.com/ruby/ruby/pull/12438

cont.c

@@ -2124,7 +2124,7 @@ rb_fiber_storage_set(VALUE self, VALUE value)
 static VALUE
 rb_fiber_storage_aref(VALUE class, VALUE key)
 {
-    Check_Type(key, T_SYMBOL);
+    key = rb_to_symbol(key);
 
     VALUE storage = fiber_storage_get(fiber_current(), FALSE);
     if (storage == Qnil) return Qnil;
@@ -2145,7 +2145,7 @@ rb_fiber_storage_aref(VALUE class, VALUE key)
 static VALUE
 rb_fiber_storage_aset(VALUE class, VALUE key, VALUE value)
 {
-    Check_Type(key, T_SYMBOL);
+    key = rb_to_symbol(key);
 
     VALUE storage = fiber_storage_get(fiber_current(), value != Qnil);
     if (storage == Qnil) return Qnil;

spec/ruby/core/fiber/storage_spec.rb

@@ -90,7 +90,9 @@ ruby_version_is "3.2" do
         key = :"#{self.class.name}#.#{self.object_id}"
         Fiber.new { Fiber[key] = 42; Fiber[key] }.resume.should == 42
       end
+    end
 
+    ruby_version_is "3.2.3"..."3.4" do
       it "can't use invalid keys" do
         invalid_keys = [Object.new, "Foo", 12]
         invalid_keys.each do |key|
@@ -99,6 +101,15 @@ ruby_version_is "3.2" do
       end
     end
 
+    ruby_version_is "3.4" do
+      it "can use keys as strings" do
+        key = Object.new
+        def key.to_str; "Foo"; end
+        Fiber[key] = 42
+        Fiber["Foo"].should == 42
+      end
+    end
+
     it "can access the storage of the parent fiber" do
       f = Fiber.new(storage: {life: 42}) do
         Fiber.new { Fiber[:life] }.resume

test/ruby/test_fiber.rb

@@ -252,6 +252,18 @@ class TestFiber < Test::Unit::TestCase
     assert_equal(nil, Thread.current[:v]);
   end
 
+  def test_fiber_variables
+    assert_equal "bar", Fiber.new {Fiber[:foo] = "bar"; Fiber[:foo]}.resume
+
+    key = :"#{self.class.name}#.#{self.object_id}"
+    Fiber[key] = 42
+    assert_equal 42, Fiber[key]
+
+    key = Object.new
+    def key.to_str; "foo"; end
+    assert_equal "Bar", Fiber.new {Fiber[key] = "Bar"; Fiber[key]}.resume
+  end
+
   def test_alive
     fib = Fiber.new{Fiber.yield}
     assert_equal(true, fib.alive?)