Fix daemon crash on malformed NamedTuple (#14119)

Fixes #14098 

Having invalid statements in a NamedTuple is almost like a syntax error,
we can remove them after giving an error (without further analysis).
This PR does almost exactly the same as
#13963 did for TypedDicts.

Co-authored-by: Shantanu <[email protected]>

Author: ilevkivskyi

mypy/nodes.py

@@ -1068,6 +1068,7 @@ class ClassDef(Statement):
         "analyzed",
         "has_incompatible_baseclass",
         "deco_line",
+        "removed_statements",
     )
 
     __match_args__ = ("name", "defs")
@@ -1086,6 +1087,8 @@ class ClassDef(Statement):
     keywords: dict[str, Expression]
     analyzed: Expression | None
     has_incompatible_baseclass: bool
+    # Used by special forms like NamedTuple and TypedDict to store invalid statements
+    removed_statements: list[Statement]
 
     def __init__(
         self,
@@ -1111,6 +1114,7 @@ def __init__(
         self.has_incompatible_baseclass = False
         # Used for error reporting (to keep backwad compatibility with pre-3.8)
         self.deco_line: int | None = None
+        self.removed_statements = []
 
     def accept(self, visitor: StatementVisitor[T]) -> T:
         return visitor.visit_class_def(self)

mypy/semanal_namedtuple.py

@@ -32,6 +32,7 @@
     NameExpr,
     PassStmt,
     RefExpr,
+    Statement,
     StrExpr,
     SymbolTable,
     SymbolTableNode,
@@ -111,7 +112,7 @@ def analyze_namedtuple_classdef(
                     if result is None:
                         # This is a valid named tuple, but some types are incomplete.
                         return True, None
-                    items, types, default_items = result
+                    items, types, default_items, statements = result
                     if is_func_scope and "@" not in defn.name:
                         defn.name += "@" + str(defn.line)
                     existing_info = None
@@ -123,31 +124,35 @@ def analyze_namedtuple_classdef(
                     defn.analyzed = NamedTupleExpr(info, is_typed=True)
                     defn.analyzed.line = defn.line
                     defn.analyzed.column = defn.column
+                    defn.defs.body = statements
                     # All done: this is a valid named tuple with all types known.
                     return True, info
         # This can't be a valid named tuple.
         return False, None
 
     def check_namedtuple_classdef(
         self, defn: ClassDef, is_stub_file: bool
-    ) -> tuple[list[str], list[Type], dict[str, Expression]] | None:
+    ) -> tuple[list[str], list[Type], dict[str, Expression], list[Statement]] | None:
         """Parse and validate fields in named tuple class definition.
 
-        Return a three tuple:
+        Return a four tuple:
           * field names
           * field types
           * field default values
+          * valid statements
         or None, if any of the types are not ready.
         """
         if self.options.python_version < (3, 6) and not is_stub_file:
             self.fail("NamedTuple class syntax is only supported in Python 3.6", defn)
-            return [], [], {}
+            return [], [], {}, []
         if len(defn.base_type_exprs) > 1:
             self.fail("NamedTuple should be a single base", defn)
         items: list[str] = []
         types: list[Type] = []
         default_items: dict[str, Expression] = {}
+        statements: list[Statement] = []
         for stmt in defn.defs.body:
+            statements.append(stmt)
             if not isinstance(stmt, AssignmentStmt):
                 # Still allow pass or ... (for empty namedtuples).
                 if isinstance(stmt, PassStmt) or (
@@ -160,9 +165,13 @@ def check_namedtuple_classdef(
                 # And docstrings.
                 if isinstance(stmt, ExpressionStmt) and isinstance(stmt.expr, StrExpr):
                     continue
+                statements.pop()
+                defn.removed_statements.append(stmt)
                 self.fail(NAMEDTUP_CLASS_ERROR, stmt)
             elif len(stmt.lvalues) > 1 or not isinstance(stmt.lvalues[0], NameExpr):
                 # An assignment, but an invalid one.
+                statements.pop()
+                defn.removed_statements.append(stmt)
                 self.fail(NAMEDTUP_CLASS_ERROR, stmt)
             else:
                 # Append name and type in this case...
@@ -199,7 +208,7 @@ def check_namedtuple_classdef(
                         )
                 else:
                     default_items[name] = stmt.rvalue
-        return items, types, default_items
+        return items, types, default_items, statements
 
     def check_namedtuple(
         self, node: Expression, var_name: str | None, is_func_scope: bool

mypy/semanal_typeddict.py

@@ -283,9 +283,11 @@ def analyze_typeddict_classdef_fields(
                 ):
                     statements.append(stmt)
                 else:
+                    defn.removed_statements.append(stmt)
                     self.fail(TPDICT_CLASS_ERROR, stmt)
             elif len(stmt.lvalues) > 1 or not isinstance(stmt.lvalues[0], NameExpr):
                 # An assignment, but an invalid one.
+                defn.removed_statements.append(stmt)
                 self.fail(TPDICT_CLASS_ERROR, stmt)
             else:
                 name = stmt.lvalues[0].name

mypy/server/aststrip.py

@@ -140,6 +140,8 @@ def visit_class_def(self, node: ClassDef) -> None:
         ]
         with self.enter_class(node.info):
             super().visit_class_def(node)
+        node.defs.body.extend(node.removed_statements)
+        node.removed_statements = []
         TypeState.reset_subtype_caches_for(node.info)
         # Kill the TypeInfo, since there is none before semantic analysis.
         node.info = CLASSDEF_NO_INFO

test-data/unit/check-class-namedtuple.test

@@ -393,8 +393,6 @@ class X(typing.NamedTuple):
 [out]
 main:6: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
 main:7: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
-main:7: error: Type cannot be declared in assignment to non-self attribute
-main:7: error: "int" has no attribute "x"
 main:9: error: Non-default NamedTuple fields cannot follow default fields
 
 [builtins fixtures/list.pyi]

test-data/unit/fine-grained.test

@@ -10205,3 +10205,75 @@ C
 [builtins fixtures/dict.pyi]
 [out]
 ==
+
+[case testNamedTupleNestedCrash]
+import m
+[file m.py]
+from typing import NamedTuple
+
+class NT(NamedTuple):
+    class C: ...
+    x: int
+    y: int
+
+[file m.py.2]
+from typing import NamedTuple
+
+class NT(NamedTuple):
+    class C: ...
+    x: int
+    y: int
+# change
+[builtins fixtures/tuple.pyi]
+[out]
+m.py:4: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
+==
+m.py:4: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
+
+[case testNamedTupleNestedClassRecheck]
+import n
+[file n.py]
+import m
+x: m.NT
+[file m.py]
+from typing import NamedTuple
+from f import A
+
+class NT(NamedTuple):
+    class C: ...
+    x: int
+    y: A
+
+[file f.py]
+A = int
+[file f.py.2]
+A = str
+[builtins fixtures/tuple.pyi]
+[out]
+m.py:5: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
+==
+m.py:5: error: Invalid statement in NamedTuple definition; expected "field_name: field_type [= default]"
+
+[case testTypedDictNestedClassRecheck]
+import n
+[file n.py]
+import m
+x: m.TD
+[file m.py]
+from typing_extensions import TypedDict
+from f import A
+
+class TD(TypedDict):
+    class C: ...
+    x: int
+    y: A
+
+[file f.py]
+A = int
+[file f.py.2]
+A = str
+[builtins fixtures/dict.pyi]
+[out]
+m.py:5: error: Invalid statement in TypedDict definition; expected "field_name: field_type"
+==
+m.py:5: error: Invalid statement in TypedDict definition; expected "field_name: field_type"