Implement and add specs for rb_struct_initialize() for both Struct and Data

* Fixes truffleruby/truffleruby#3997

Author: eregon

optional/capi/ext/struct_spec.c

@@ -62,6 +62,10 @@ static VALUE struct_spec_rb_struct_size(VALUE self, VALUE st) {
   return rb_struct_size(st);
 }
 
+static VALUE struct_spec_rb_struct_initialize(VALUE self, VALUE st, VALUE values) {
+  return rb_struct_initialize(st, values);
+}
+
 #if defined(RUBY_VERSION_IS_3_3)
 /* Only allow setting three attributes, should be sufficient for testing. */
 static VALUE struct_spec_rb_data_define(VALUE self, VALUE superclass,
@@ -90,6 +94,7 @@ void Init_struct_spec(void) {
   rb_define_method(cls, "rb_struct_define_under", struct_spec_rb_struct_define_under, 5);
   rb_define_method(cls, "rb_struct_new", struct_spec_rb_struct_new, 4);
   rb_define_method(cls, "rb_struct_size", struct_spec_rb_struct_size, 1);
+  rb_define_method(cls, "rb_struct_initialize", struct_spec_rb_struct_initialize, 2);
 #if defined(RUBY_VERSION_IS_3_3)
   rb_define_method(cls, "rb_data_define", struct_spec_rb_data_define, 4);
 #endif

optional/capi/struct_spec.rb

@@ -208,20 +208,48 @@
       @s.rb_struct_size(@struct).should == 3
     end
   end
+
+  describe "rb_struct_initialize" do
+    it "sets all members" do
+      @s.rb_struct_initialize(@struct, [1, 2, 3]).should == nil
+      @struct.a.should == 1
+      @struct.b.should == 2
+      @struct.c.should == 3
+    end
+
+    it "does not freeze the Struct instance" do
+      @s.rb_struct_initialize(@struct, [1, 2, 3]).should == nil
+      @struct.should_not.frozen?
+      @s.rb_struct_initialize(@struct, [4, 5, 6]).should == nil
+      @struct.a.should == 4
+      @struct.b.should == 5
+      @struct.c.should == 6
+    end
+
+    it "raises ArgumentError if too many values" do
+      -> { @s.rb_struct_initialize(@struct, [1, 2, 3, 4]) }.should raise_error(ArgumentError, "struct size differs")
+    end
+
+    it "treats missing values as nil" do
+      @s.rb_struct_initialize(@struct, [1, 2]).should == nil
+      @struct.a.should == 1
+      @struct.b.should == 2
+      @struct.c.should == nil
+    end
+  end
 end
 
 ruby_version_is "3.3" do
   describe "C-API Data function" do
-    before :each do
+    before :all do
       @s = CApiStructSpecs.new
+      @klass = @s.rb_data_define(nil, "a", "b", "c")
     end
 
     describe "rb_data_define" do
       it "returns a subclass of Data class when passed nil as the first argument" do
-        klass = @s.rb_data_define(nil, "a", "b", "c")
-
-        klass.should.is_a? Class
-        klass.superclass.should == Data
+        @klass.should.is_a? Class
+        @klass.superclass.should == Data
       end
 
       it "returns a subclass of a class when passed as the first argument" do
@@ -233,17 +261,15 @@
       end
 
       it "creates readers for the members" do
-        klass = @s.rb_data_define(nil, "a", "b", "c")
-        obj = klass.new(1, 2, 3)
+        obj = @klass.new(1, 2, 3)
 
         obj.a.should == 1
         obj.b.should == 2
         obj.c.should == 3
       end
 
       it "returns the member names as Symbols" do
-        klass = @s.rb_data_define(nil, "a", "b", "c")
-        obj = klass.new(0, 0, 0)
+        obj = @klass.new(0, 0, 0)
 
         obj.members.should == [:a, :b, :c]
       end
@@ -256,5 +282,35 @@
         -> { @s.rb_data_define([], "a", "b", "c") }.should raise_error(TypeError, "wrong argument type Array (expected Class)")
       end
     end
+
+    describe "rb_struct_initialize" do
+      it "sets all members for a Data instance" do
+        data = @klass.allocate
+        @s.rb_struct_initialize(data, [1, 2, 3]).should == nil
+        data.a.should == 1
+        data.b.should == 2
+        data.c.should == 3
+      end
+
+      it "freezes the Data instance" do
+        data = @klass.allocate
+        @s.rb_struct_initialize(data, [1, 2, 3]).should == nil
+        data.should.frozen?
+        -> { @s.rb_struct_initialize(data, [1, 2, 3]) }.should raise_error(FrozenError)
+      end
+
+      it "raises ArgumentError if too many values" do
+        data = @klass.allocate
+        -> { @s.rb_struct_initialize(data, [1, 2, 3, 4]) }.should raise_error(ArgumentError, "struct size differs")
+      end
+
+      it "treats missing values as nil" do
+        data = @klass.allocate
+        @s.rb_struct_initialize(data, [1, 2]).should == nil
+        data.a.should == 1
+        data.b.should == 2
+        data.c.should == nil
+      end
+    end
   end
 end