[issue46900] marshal.dumps represents the same list object differently

[Raymond Hettinger]

Raymond Hettinger <raymond.hettinger at gmail.com> added the comment:

The difference is the FLAG_REF which is set to 128 (0x80). 

>>> import marshal
>>> var_example = [(1,2,3),(4,5,6)]
>>> vm = marshal.dumps(var_example)
>>> rm = marshal.dumps([(1,2,3),(4,5,6)])
>>> [v ^ r for v, r in zip(vm, rm)]
[128, 0, 0, 0, 0, 128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

Whether a flag for possible reuse is generated depends on the reference count of a object.

When passing in the list as variable, the reference count is higher than passing it as a literal.


 That flag tells marshal whether to generate an index entry.  Whether that occurs re

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nosy: +rhettinger

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue46900>
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