RustPython · youknowone · Jan 22, 2026 · Jan 22, 2026 · Jan 20, 2026
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
@@ -463,6 +463,11 @@ jobs:
 
       - run: ruff format --check
 
+      - name: run update_lib tests
+        run: cargo run -- -m unittest discover -s scripts/update_lib/tests -v
+        env:
+          PYTHONPATH: scripts
+
       - name: install prettier
         run: yarn global add prettier && echo "$(yarn global bin)" >>$GITHUB_PATH
 

diff --git a/crates/vm/src/stdlib/ast/pyast.rs b/crates/vm/src/stdlib/ast/pyast.rs
@@ -2,6 +2,8 @@
 
 use super::*;
 use crate::common::ascii;
+use crate::function::FuncArgs;
+use crate::types::Initializer;
 
 macro_rules! impl_node {
     (
@@ -462,12 +464,54 @@ impl_node!(
     attributes: ["lineno", "col_offset", "end_lineno", "end_col_offset"],
 );
 
-impl_node!(
-    #[pyclass(module = "_ast", name = "Constant", base = NodeExpr)]
-    pub(crate) struct NodeExprConstant,
-    fields: ["value", "kind"],
-    attributes: ["lineno", "col_offset", "end_lineno", "end_col_offset"],
-);
+// NodeExprConstant needs custom Initializer to default kind to None
+#[pyclass(module = "_ast", name = "Constant", base = NodeExpr)]
+#[repr(transparent)]
+pub(crate) struct NodeExprConstant(NodeExpr);
+
+#[pyclass(flags(HAS_DICT, BASETYPE), with(Initializer))]
+impl NodeExprConstant {
+    #[extend_class]
+    fn extend_class_with_fields(ctx: &Context, class: &'static Py<PyType>) {
+        class.set_attr(
+            identifier!(ctx, _fields),
+            ctx.new_tuple(vec![
+                ctx.new_str(ascii!("value")).into(),
+                ctx.new_str(ascii!("kind")).into(),
+            ])
+            .into(),
+        );
+
+        class.set_attr(
+            identifier!(ctx, _attributes),
+            ctx.new_list(vec![
+                ctx.new_str(ascii!("lineno")).into(),
+                ctx.new_str(ascii!("col_offset")).into(),
+                ctx.new_str(ascii!("end_lineno")).into(),
+                ctx.new_str(ascii!("end_col_offset")).into(),
+            ])
+            .into(),
+        );
+    }
+}
+
+impl Initializer for NodeExprConstant {
+    type Args = FuncArgs;
+
+    fn slot_init(zelf: PyObjectRef, args: FuncArgs, vm: &VirtualMachine) -> PyResult<()> {
+        <NodeAst as Initializer>::slot_init(zelf.clone(), args, vm)?;
+        // kind defaults to None if not provided
+        let dict = zelf.as_object().dict().unwrap();
+        if !dict.contains_key("kind", vm) {
+            dict.set_item("kind", vm.ctx.none(), vm)?;
+        }
+        Ok(())
+    }
+
+    fn init(_zelf: PyRef<Self>, _args: Self::Args, _vm: &VirtualMachine) -> PyResult<()> {
+        unreachable!("slot_init is defined")
+    }
+}
 
 impl_node!(
     #[pyclass(module = "_ast", name = "Attribute", base = NodeExpr)]

diff --git a/crates/vm/src/stdlib/ast/python.rs b/crates/vm/src/stdlib/ast/python.rs
@@ -80,6 +80,7 @@ pub(crate) mod _ast {
                 }
                 zelf.set_attr(vm.ctx.intern_str(key), value, vm)?;
             }
+
             Ok(())
         }
-Original file line number
+Diff line change
@@ Expand Up / @@ -80,6 +80,7 @@ pub(crate) mod _ast { @@
                     }
                     zelf.set_attr(vm.ctx.intern_str(key), value, vm)?;
                 }
                 Ok(())
             }
@@ Expand Down @@