Merge branch '3.1.x' into 3.2.x

Author: scoder

CHANGES.rst

@@ -515,7 +515,7 @@ Other changes
   (Github issue :issue:`6423`)
 
 
-3.1.7 (2025-11-??)
+3.1.7 (2025-11-11)
 ==================
 
 Bugs fixed
@@ -526,6 +526,9 @@ Bugs fixed
   Also, lone surrogates failed to format in this way.
   (Github issue :issue:`7298`)
 
+* Assigning nested structs from a list of structs (item by item) could crash Cython.
+  (Github issue :issue:`7308`)
+
 * Cython incorrectly called ``PyList_GetItemRef()`` in PyPy and GraalPython before Py3.13.
   (Github issue :issue:`7269`)
 

Cython/Compiler/ExprNodes.py

@@ -9170,9 +9170,12 @@ def coerce_to(self, dst_type, env):
             else:
                 if len(self.args) < len(dst_type.scope.var_entries):
                     warning(self.pos, "Too few members for '%s'" % dst_type, 1)
-                for i, (arg, member) in enumerate(zip(self.original_args, dst_type.scope.var_entries)):
+                for i, (arg, coerced_arg, member) in enumerate(zip(self.original_args, self.args, dst_type.scope.var_entries)):
                     if isinstance(arg, CoerceToPyTypeNode):
                         arg = arg.arg
+                    elif member.type.is_struct_or_union and coerced_arg.is_dict_literal:
+                        # For struct assignments, use the coerced dict directly, not a struct type call etc.
+                        arg = coerced_arg
                     self.args[i] = arg.coerce_to(member.type, env)
             self.type = dst_type
         elif dst_type.is_ctuple:

tests/run/cstruct.pyx

@@ -105,3 +105,53 @@ def reserved_names():
     s2.new = s1.new
     s2.case, s2.do = s1.case, s1.do
     return (s2.new, s2.case, s2.do)
+
+
+cdef struct Point:
+    double x,y
+    int colour
+
+cdef union int_or_float:
+    int i
+    float f
+
+cdef struct NestedStruct:
+    Point p
+    int_or_float x
+
+
+def struct_union_assignments():
+    """
+    >>> struct_union_assignments()
+    """
+    cdef NestedStruct ns
+
+    ns = [Point(1.0, 2.0, 42), int_or_float(i=1)]
+    assert ns.p.colour == 42, ns.p.colour
+    assert ns.p.x == 1.0, ns.p.x
+    assert ns.p.y == 2.0, ns.p.y
+    assert ns.x.i == 1, ns.x.i
+
+    ns = NestedStruct(Point(x=2.0, y=3.0, colour=43), int_or_float(i=2))
+    assert ns.p.colour == 43, ns.p.colour
+    assert ns.p.x == 2.0, ns.p.x
+    assert ns.p.y == 3.0, ns.p.y
+    assert ns.x.i == 2, ns.x.i
+
+    ns = NestedStruct(x=int_or_float(i=3), p=Point(colour=44, y=4.0, x=3.0))
+    assert ns.p.colour == 44, ns.p.colour
+    assert ns.p.x == 3.0, ns.p.x
+    assert ns.p.y == 4.0, ns.p.y
+    assert ns.x.i == 3, ns.x.i
+
+    ns = NestedStruct([4.0, 5.0, 45], x=int_or_float(i=4))
+    assert ns.p.colour == 45, ns.p.colour
+    assert ns.p.x == 4.0, ns.p.x
+    assert ns.p.y == 5.0, ns.p.y
+    assert ns.x.i == 4, ns.x.i
+
+    ns = [[4.0, 5.0, 46], int_or_float(i=5)]
+    assert ns.p.colour == 46, ns.p.colour
+    assert ns.p.x == 4.0, ns.p.x
+    assert ns.p.y == 5.0, ns.p.y
+    assert ns.x.i == 5, ns.x.i