Fixes #1807: 2.3.0 regression: <class 'bytes'> is not converted to std::vector<uint8_t> anymore

Author: cdump

include/pybind11/stl.h

@@ -144,7 +144,7 @@ template <typename Type, typename Value> struct list_caster {
     using value_conv = make_caster<Value>;
 
     bool load(handle src, bool convert) {
-        if (!isinstance<sequence>(src) || isinstance<str>(src))
+        if (!isinstance<sequence>(src) || (!isinstance<bytes>(src) && isinstance<str>(src)))
             return false;
         auto s = reinterpret_borrow<sequence>(src);
         value.clear();

tests/test_stl.cpp

@@ -251,6 +251,9 @@ TEST_SUBMODULE(stl, m) {
     m.def("func_with_string_or_vector_string_arg_overload", [](std::list<std::string>) { return 2; });
     m.def("func_with_string_or_vector_string_arg_overload", [](std::string) { return 3; });
 
+    // #1807: 2.3.0 regression: <class 'bytes'> is not converted to std::vector<uint8_t> anymore
+    m.def("func_with_vector_uint8_t_arg", [](std::vector<uint8_t> v) { return v.size(); });
+
     class Placeholder {
     public:
         Placeholder() { print_created(this); }

tests/test_stl.py

@@ -220,6 +220,13 @@ def test_function_with_string_and_vector_string_arg():
     assert m.func_with_string_or_vector_string_arg_overload('A') == 3
 
 
+def test_bytes_to_vector_uint8_t():
+    """Check if a bytes is implicitly converted to std::vector<uint8_t>, issue #1807"""
+    assert m.func_with_vector_uint8_t_arg(b'abc') == 3
+    with pytest.raises(TypeError):
+        m.func_with_vector_uint8_t_arg('stringval')
+
+
 def test_stl_ownership():
     cstats = ConstructorStats.get(m.Placeholder)
     assert cstats.alive() == 0