Improve error message when assigning tuples of incorrect size to a ctuple. Previously, it said "Expected tuple of size 4, got tuple", which is unhelpful and confusing.

1 files changed, 6 insertions, 2 deletions

diff --git a/Cython/Utility/TypeConversion.c b/Cython/Utility/TypeConversion.c
index 6c454d145..9ca29a0f0 100644
--- a/Cython/Utility/TypeConversion.c
+++ b/Cython/Utility/TypeConversion.c
@@ -576,12 +576,16 @@ static {{struct_type_decl}} {{funcname}}(PyObject *);
 static {{struct_type_decl}} {{funcname}}(PyObject * o) {
     {{struct_type_decl}} result;
 
-    if (!PyTuple_Check(o) || PyTuple_GET_SIZE(o) != {{size}}) {
+    if (unlikely(!PyTuple_Check(o))) {
         __Pyx_TypeName o_type_name = __Pyx_PyType_GetName(Py_TYPE(o));
         PyErr_Format(PyExc_TypeError,
-                     "Expected a tuple of size %d, got " __Pyx_FMT_TYPENAME, {{size}}, o_type_name);
+                     "Expected a tuple of size %zd, got " __Pyx_FMT_TYPENAME, (Py_ssize_t) {{size}}, o_type_name);
         __Pyx_DECREF_TypeName(o_type_name);
         goto bad;
+    } else if (unlikely(PyTuple_GET_SIZE(o) != {{size}})) {
+        PyErr_Format(PyExc_TypeError,
+                     "Expected a tuple of size %zd, got size %zd", (Py_ssize_t) {{size}}, PyTuple_GET_SIZE(o));
+        goto bad;
     }
 
 #if CYTHON_ASSUME_SAFE_MACROS && !CYTHON_AVOID_BORROWED_REFS