Merge pull request RustPython#4217 from oow214/type_annotations

Add annotations for type

Author: youknowone

Lib/test/test_opcodes.py

@@ -33,8 +33,6 @@ def test_setup_annotations_line(self):
         except OSError:
             pass
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_default_annotations_exist(self):
         class C: pass
         self.assertEqual(C.__annotations__, {})

vm/src/builtins/type.rs

@@ -521,6 +521,60 @@ impl PyType {
         Ok(())
     }
 
+    #[pygetset(magic)]
+    fn annotations(&self, vm: &VirtualMachine) -> PyResult<PyObjectRef> {
+        if !self.slots.flags.has_feature(PyTypeFlags::HEAPTYPE) {
+            return Err(vm.new_attribute_error(format!(
+                "type object '{}' has no attribute '__annotations__'",
+                self.name()
+            )));
+        }
+
+        let __annotations__ = identifier!(vm, __annotations__);
+        let annotations = self.attributes.read().get(__annotations__).cloned();
+
+        let annotations = if let Some(annotations) = annotations {
+            annotations
+        } else {
+            let annotations: PyObjectRef = vm.ctx.new_dict().into();
+            let removed = self
+                .attributes
+                .write()
+                .insert(__annotations__, annotations.clone());
+            debug_assert!(removed.is_none());
+            annotations
+        };
+        Ok(annotations)
+    }
+
+    #[pygetset(magic, setter)]
+    fn set_annotations(&self, value: Option<PyObjectRef>, vm: &VirtualMachine) -> PyResult<()> {
+        if self.slots.flags.has_feature(PyTypeFlags::IMMUTABLETYPE) {
+            return Err(vm.new_type_error(format!(
+                "cannot set '__annotations__' attribute of immutable type '{}'",
+                self.name()
+            )));
+        }
+
+        let __annotations__ = identifier!(vm, __annotations__);
+        if let Some(value) = value {
+            self.attributes.write().insert(__annotations__, value);
+        } else {
+            self.attributes
+                .read()
+                .get(__annotations__)
+                .cloned()
+                .ok_or_else(|| {
+                    vm.new_attribute_error(format!(
+                        "'{}' object has no attribute '__annotations__'",
+                        self.name()
+                    ))
+                })?;
+        }
+
+        Ok(())
+    }
+
     #[pygetset(magic)]
     pub fn module(&self, vm: &VirtualMachine) -> PyObjectRef {
         self.attributes

vm/src/types/slot.rs

@@ -105,6 +105,7 @@ impl std::fmt::Debug for PyTypeSlots {
 bitflags! {
     #[non_exhaustive]
     pub struct PyTypeFlags: u64 {
+        const IMMUTABLETYPE = 1 << 8;
         const HEAPTYPE = 1 << 9;
         const BASETYPE = 1 << 10;
         const METHOD_DESCR = 1 << 17;