Changing pybind11::str to exclusively hold PyUnicodeObject (#2409)

* Changing pybind11::str to exclusively hold PyUnicodeObject

tests/test_pytypes.py

@@ -120,14 +120,17 @@ def test_str(doc):
     assert s1 == s2
 
     malformed_utf8 = b"\x80"
-    assert m.str_from_object(malformed_utf8) is malformed_utf8  # To be fixed; see #2380
+    if hasattr(m, "PYBIND11_STR_LEGACY_PERMISSIVE"):
+        assert m.str_from_object(malformed_utf8) is malformed_utf8
+    elif env.PY2:
+        with pytest.raises(UnicodeDecodeError):
+            m.str_from_object(malformed_utf8)
+    else:
+        assert m.str_from_object(malformed_utf8) == "b'\\x80'"
     if env.PY2:
-        # with pytest.raises(UnicodeDecodeError):
-        #     m.str_from_object(malformed_utf8)
         with pytest.raises(UnicodeDecodeError):
             m.str_from_handle(malformed_utf8)
     else:
-        # assert m.str_from_object(malformed_utf8) == "b'\\x80'"
         assert m.str_from_handle(malformed_utf8) == "b'\\x80'"
 
 
@@ -303,13 +306,26 @@ def test_pybind11_str_raw_str():
     valid_orig = u"DZ"
     valid_utf8 = valid_orig.encode("utf-8")
     valid_cvt = cvt(valid_utf8)
-    assert type(valid_cvt) == bytes  # Probably surprising.
-    assert valid_cvt == b"\xc7\xb1"
+    if hasattr(m, "PYBIND11_STR_LEGACY_PERMISSIVE"):
+        assert valid_cvt is valid_utf8
+    else:
+        assert type(valid_cvt) is unicode if env.PY2 else str  # noqa: F821
+        if env.PY2:
+            assert valid_cvt == valid_orig
+        else:
+            assert valid_cvt == "b'\\xc7\\xb1'"
 
     malformed_utf8 = b"\x80"
-    malformed_cvt = cvt(malformed_utf8)
-    assert type(malformed_cvt) == bytes  # Probably surprising.
-    assert malformed_cvt == b"\x80"
+    if hasattr(m, "PYBIND11_STR_LEGACY_PERMISSIVE"):
+        assert cvt(malformed_utf8) is malformed_utf8
+    else:
+        if env.PY2:
+            with pytest.raises(UnicodeDecodeError):
+                cvt(malformed_utf8)
+        else:
+            malformed_cvt = cvt(malformed_utf8)
+            assert type(malformed_cvt) is str
+            assert malformed_cvt == "b'\\x80'"
 
 
 def test_implicit_casting():
@@ -488,3 +504,40 @@ def test_builtin_functions():
         "object of type 'generator' has no len()",
         "'generator' has no length",
     ]  # PyPy
+
+
+def test_isinstance_string_types():
+    assert m.isinstance_pybind11_bytes(b"")
+    assert not m.isinstance_pybind11_bytes(u"")
+
+    assert m.isinstance_pybind11_str(u"")
+    if hasattr(m, "PYBIND11_STR_LEGACY_PERMISSIVE"):
+        assert m.isinstance_pybind11_str(b"")
+    else:
+        assert not m.isinstance_pybind11_str(b"")
+
+
+def test_pass_bytes_or_unicode_to_string_types():
+    assert m.pass_to_pybind11_bytes(b"Bytes") == 5
+    with pytest.raises(TypeError):
+        m.pass_to_pybind11_bytes(u"Str")
+
+    if hasattr(m, "PYBIND11_STR_LEGACY_PERMISSIVE") or env.PY2:
+        assert m.pass_to_pybind11_str(b"Bytes") == 5
+    else:
+        with pytest.raises(TypeError):
+            m.pass_to_pybind11_str(b"Bytes")
+    assert m.pass_to_pybind11_str(u"Str") == 3
+
+    assert m.pass_to_std_string(b"Bytes") == 5
+    assert m.pass_to_std_string(u"Str") == 3
+
+    malformed_utf8 = b"\x80"
+    if hasattr(m, "PYBIND11_STR_LEGACY_PERMISSIVE"):
+        assert m.pass_to_pybind11_str(malformed_utf8) == 1
+    elif env.PY2:
+        with pytest.raises(UnicodeDecodeError):
+            m.pass_to_pybind11_str(malformed_utf8)
+    else:
+        with pytest.raises(TypeError):
+            m.pass_to_pybind11_str(malformed_utf8)