issue 147: force-compute nested structs before parent structs

src/c/_cffi_backend.c

@@ -5238,6 +5238,13 @@ static PyObject *b_complete_struct_or_union(PyObject *self, PyObject *args)
                               &fbitsize, &foffset))
             goto error;
 
+        if ((ftype->ct_flags & (CT_STRUCT | CT_UNION)) &&
+            !(ftype->ct_flags & CT_IS_OPAQUE)) {
+            /* force now the type of the nested field */
+            if (force_lazy_struct(ftype) < 0)
+                return NULL;
+        }
+
         if (ftype->ct_size < 0) {
             if ((ftype->ct_flags & CT_ARRAY) && fbitsize < 0
                     && (i == nb_fields - 1 || foffset != -1)) {
@@ -5252,9 +5259,6 @@ static PyObject *b_complete_struct_or_union(PyObject *self, PyObject *args)
             }
         }
         else if (ftype->ct_flags & (CT_STRUCT|CT_UNION)) {
-            if (force_lazy_struct(ftype) < 0)   /* for CT_WITH_VAR_ARRAY */
-                return NULL;
-
             /* GCC (or maybe C99) accepts var-sized struct fields that are not
                the last field of a larger struct.  That's why there is no
                check here for "last field": we propagate the flag

src/c/cdlopen.c

@@ -81,7 +81,7 @@ static PyObject *ffi_dlclose(PyObject *self, PyObject *args)
 
 static Py_ssize_t cdl_4bytes(char *src)
 {
-    /* read 4 bytes in little-endian order; return it as a signed integer */
+    /* read 4 bytes in big-endian order; return it as a signed integer */
     signed char *ssrc = (signed char *)src;
     unsigned char *usrc = (unsigned char *)src;
     return (ssrc[0] << 24) | (usrc[1] << 16) | (usrc[2] << 8) | usrc[3];

testing/cffi1/test_re_python.py

@@ -286,3 +286,33 @@ def test_dlopen_handle():
 
     err = lib1.dlclose(handle)
     assert err == 0
+
+def test_rec_structs_1():
+    ffi = FFI()
+    ffi.cdef("struct B { struct C* c; }; struct C { struct B b; };")
+    ffi.set_source('test_rec_structs_1', None)
+    ffi.emit_python_code(str(tmpdir.join('_rec_structs_1.py')))
+    #
+    if sys.version_info[:2] >= (3, 3):
+        import importlib
+        importlib.invalidate_caches()  # issue 197, maybe
+    #
+    from _rec_structs_1 import ffi
+    # the following line used to raise TypeError
+    # unless preceeded by 'ffi.sizeof("struct C")'.
+    sz = ffi.sizeof("struct B")
+    assert sz == ffi.sizeof("int *")
+
+def test_rec_structs_2():
+    ffi = FFI()
+    ffi.cdef("struct B { struct C* c; }; struct C { struct B b; };")
+    ffi.set_source('test_rec_structs_2', None)
+    ffi.emit_python_code(str(tmpdir.join('_rec_structs_2.py')))
+    #
+    if sys.version_info[:2] >= (3, 3):
+        import importlib
+        importlib.invalidate_caches()  # issue 197, maybe
+    #
+    from _rec_structs_2 import ffi
+    sz = ffi.sizeof("struct C")
+    assert sz == ffi.sizeof("int *")