[mypyc] Add primitive type for bytearray

python · JukkaL · Jan 9, 2026 · Jan 8, 2026 · Jan 8, 2026 · Jan 8, 2026
commit 27fe2f67b7e6d65d59440558fd52c606e9b52faf
diff --git a/mypyc/codegen/emit.py b/mypyc/codegen/emit.py
@@ -33,6 +33,7 @@
     RUnion,
     int_rprimitive,
     is_bool_or_bit_rprimitive,
+    is_bytearray_rprimitive,
     is_bytes_rprimitive,
     is_dict_rprimitive,
     is_fixed_width_rtype,
@@ -664,6 +665,16 @@ def emit_cast(
             self.emit_lines(f"    {dest} = {src};", "else {")
             self.emit_cast_error_handler(error, src, dest, typ, raise_exception)
             self.emit_line("}")
+        elif is_bytearray_rprimitive(typ):
+            if declare_dest:
+                self.emit_line(f"PyObject *{dest};")
+            check = "(PyByteArray_Check({}))"
+            if likely:
+                check = f"(likely{check})"
+            self.emit_arg_check(src, dest, typ, check.format(src, src), optional)
+            self.emit_lines(f"    {dest} = {src};", "else {")
+            self.emit_cast_error_handler(error, src, dest, typ, raise_exception)
+            self.emit_line("}")
         elif is_tuple_rprimitive(typ):
             if declare_dest:
                 self.emit_line(f"{self.ctype(typ)} {dest};")

diff --git a/mypyc/ir/rtypes.py b/mypyc/ir/rtypes.py
@@ -504,6 +504,9 @@ def __hash__(self) -> int:
 # Python bytes object.
 bytes_rprimitive: Final = RPrimitive("builtins.bytes", is_unboxed=False, is_refcounted=True)
 
+# Python bytearray object.
+bytearray_rprimitive: Final = RPrimitive("builtins.bytearray", is_unboxed=False, is_refcounted=True)
+
 # Tuple of an arbitrary length (corresponds to Tuple[t, ...], with
 # explicit '...').
 tuple_rprimitive: Final = RPrimitive("builtins.tuple", is_unboxed=False, is_refcounted=True)
@@ -632,6 +635,10 @@ def is_bytes_rprimitive(rtype: RType) -> TypeGuard[RPrimitive]:
     return isinstance(rtype, RPrimitive) and rtype.name == "builtins.bytes"
 
 
+def is_bytearray_rprimitive(rtype: RType) -> TypeGuard[RPrimitive]:
+    return isinstance(rtype, RPrimitive) and rtype.name == "builtins.bytearray"
+
+
 def is_tuple_rprimitive(rtype: RType) -> TypeGuard[RPrimitive]:
     return isinstance(rtype, RPrimitive) and rtype.name == "builtins.tuple"
 
@@ -646,6 +653,7 @@ def is_sequence_rprimitive(rtype: RType) -> TypeGuard[RPrimitive]:
         or is_tuple_rprimitive(rtype)
         or is_str_rprimitive(rtype)
         or is_bytes_rprimitive(rtype)
+        or is_bytearray_rprimitive(rtype)
     )
 
 

diff --git a/mypyc/irbuild/mapper.py b/mypyc/irbuild/mapper.py
@@ -31,6 +31,7 @@
     RType,
     RUnion,
     bool_rprimitive,
+    bytearray_rprimitive,
     bytes_rprimitive,
     dict_rprimitive,
     float_rprimitive,
@@ -88,6 +89,8 @@ def type_to_rtype(self, typ: Type | None) -> RType:
                 return str_rprimitive
             elif typ.type.fullname == "builtins.bytes":
                 return bytes_rprimitive
+            elif typ.type.fullname == "builtins.bytearray":
+                return bytearray_rprimitive
             elif typ.type.fullname == "builtins.list":
                 return list_rprimitive
             # Dict subclasses are at least somewhat common and we

diff --git a/mypyc/primitives/bytes_ops.py b/mypyc/primitives/bytes_ops.py
@@ -8,6 +8,7 @@
     RUnion,
     bit_rprimitive,
     bool_rprimitive,
+    bytearray_rprimitive,
     bytes_rprimitive,
     c_int_rprimitive,
     c_pyssize_t_rprimitive,
@@ -51,7 +52,7 @@
 function_op(
     name="builtins.bytearray",
     arg_types=[object_rprimitive],
-    return_type=object_rprimitive,
+    return_type=bytearray_rprimitive,
     c_function_name="PyByteArray_FromObject",
     error_kind=ERR_MAGIC,
 )

diff --git a/mypyc/test-data/irbuild-bytes.test b/mypyc/test-data/irbuild-bytes.test
@@ -50,18 +50,22 @@ def f(s, num):
     num :: int
     r0 :: object
     r1 :: str
-    r2, r3, a, r4, b, r5, r6, c :: object
+    r2, r3 :: object
+    r4, a, r5, b :: bytearray
+    r6 :: object
+    r7, c :: bytearray
 L0:
     r0 = builtins :: module
     r1 = 'bytearray'
     r2 = CPyObject_GetAttr(r0, r1)
     r3 = PyObject_Vectorcall(r2, 0, 0, 0)
-    a = r3
-    r4 = PyByteArray_FromObject(s)
-    b = r4
-    r5 = box(int, num)
-    r6 = PyByteArray_FromObject(r5)
-    c = r6
+    r4 = cast(bytearray, r3)
+    a = r4
+    r5 = PyByteArray_FromObject(s)
+    b = r5
+    r6 = box(int, num)
+    r7 = PyByteArray_FromObject(r6)
+    c = r7
     return 1
 
 [case testBytesEquality]