Status: New
Owner: ken...@google.com
Labels: Type-Defect Priority-Medium
New issue 208 by kleptog: python: constructor does not type check scalar
values
http://code.google.com/p/protobuf/issues/detail?id=208
What steps will reproduce the problem?
1. Create a simple protocol file, such as (test.proto):
--- cut ---
message CompositeType {
required int32 stamp = 1;
}
--- cut ---
2. compile the protocol to python using protoc.
3. Execute the following interactively:
In [1]: from test_pb2 import *
In [2]: c=CompositeType(stamp='foobar')
# Now we have a string in an integer field
In [3]: print c
stamp: foobar
# Serialisation blows up
In [4]: c.SerializeToString()
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
/tmp/<ipython console> in <module>()
... lots of traceback data ...
TypeError: unsupported operand type(s) for &: 'str' and 'int'
What is the expected output? What do you see instead?
I expected the creation of the object to throw a TypeError exception. A
direct assignment of the same value produces:
In [5]: c.stamp='foobar'
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
... lots of traceback ...
TypeError: 'foobar' has type <type 'str'>, but expected one of:
(<type 'int'>, <type 'long'>)
which is expected.
What version of the product are you using? On what operating system?
protobuf 2.3.0 on python 2.5 on Debian 5.0
Please provide any additional information below.
This is simply a case of the constructor being cute and bypassing the
proper handlers for setting values. This can be solved by changing one line
in reflection.py:_AddInitMethod.init. Replace:
self._fields[field] = field_value
in the final else: with
setattr(self, field, field_value)
which will call the appropriate type checker.
Note that for non-scalar fields it doesn't type check either but because it
uses MergeFrom you don't get exceptions from deep within the serialisation
code, so I don't think that's as much of a problem.
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