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author | Guido van Rossum <guido@python.org> | 2001-09-25 03:43:42 +0000 |
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committer | Guido van Rossum <guido@python.org> | 2001-09-25 03:43:42 +0000 |
commit | 38e5222a3cb1b521e9164e840c6b5fb8aca9e9eb (patch) | |
tree | a7f6329ff72c2e531743c1b07f488a98f2aa9d12 /Lib | |
parent | b0108f02dce8812631b884ab1e35fad44fd8a1fa (diff) | |
download | cpython-38e5222a3cb1b521e9164e840c6b5fb8aca9e9eb.tar.gz |
Make __class__ assignment possible, when the object structures are the
same. I hope the test for structural equivalence is stringent enough.
It only allows the assignment if the old and new types:
- have the same basic size
- have the same item size
- have the same dict offset
- have the same weaklist offset
- have the same GC flag bit
- have a common base that is the same except for maybe the dict and
weaklist (which may have been added separately at the same offsets
in both types)
Diffstat (limited to 'Lib')
-rw-r--r-- | Lib/test/test_descr.py | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py index 5bd837e6f2..766c399dcd 100644 --- a/Lib/test/test_descr.py +++ b/Lib/test/test_descr.py @@ -2005,6 +2005,33 @@ def descrdoc(): check(file.closed, "flag set if the file is closed") # getset descriptor check(file.name, "file name") # member descriptor +def setclass(): + if verbose: print "Testing __class__ assignment..." + class C(object): pass + class D(object): pass + class E(object): pass + class F(D, E): pass + for cls in C, D, E, F: + for cls2 in C, D, E, F: + x = cls() + x.__class__ = cls2 + verify(x.__class__ is cls2) + x.__class__ = cls + verify(x.__class__ is cls) + def cant(x, C): + try: + x.__class__ = C + except TypeError: + pass + else: + raise TestFailed, "shouldn't allow %r.__class__ = %r" % (x, C) + cant(C(), list) + cant(list(), C) + cant(C(), 1) + cant(C(), object) + cant(object(), list) + cant(list(), object) + def test_main(): lists() @@ -2047,6 +2074,7 @@ def test_main(): rich_comparisons() coercions() descrdoc() + setclass() if verbose: print "All OK" if __name__ == "__main__": |