Re: [Python-Dev] [Python-checkins] cpython (3.3): Issue #16045: add more unit tests for built-in int()
On 23.12.12 22:03, Terry Reedy wrote: I think the above behavior is buggy and should be changed rather than frozen into CPython with a test. According to the docs, PyPy does it right. http://bugs.python.org/issue16761 ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] [Python-checkins] cpython (3.3): Issue #16045: add more unit tests for built-in int()
+# For example, PyPy 1.9.0 raised TypeError for these cases because it +# expects x to be a string if base is given. +@support.cpython_only +def test_base_arg_with_no_x_arg(self): +self.assertEquals(int(base=6), 0) +# Even invalid bases don't raise an exception. +self.assertEquals(int(base=1), 0) +self.assertEquals(int(base=1000), 0) +self.assertEquals(int(base='foo'), 0) I think the above behavior is buggy and should be changed rather than frozen into CPython with a test. According to the docs, PyPy does it right. The current online doc gives the signature as int(x=0) int(x, base=10) where x is s string The 3.3.0 docstring says When converting a string, use the optional base. It is an error to supply a base when converting a non-string. Certainly, accepting any object as a base, violating The allowed values are 0 and 2-36. just because giving a base is itself invalid is crazy. -- Terry Jan Reedy ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] [Python-checkins] cpython (3.3): Issue #16045: add more unit tests for built-in int()
On Sun, Dec 23, 2012 at 12:03 PM, Terry Reedy tjre...@udel.edu wrote: +# For example, PyPy 1.9.0 raised TypeError for these cases because it +# expects x to be a string if base is given. +@support.cpython_only +def test_base_arg_with_no_x_arg(self): +self.assertEquals(int(base=6), 0) +# Even invalid bases don't raise an exception. +self.assertEquals(int(base=1), 0) +self.assertEquals(int(base=1000), 0) +self.assertEquals(int(base='foo'), 0) I think the above behavior is buggy and should be changed rather than frozen into CPython with a test. According to the docs, PyPy does it right. I support further discussion here. (I did draft the patch, but it was a first version. I did not commit the patch.) The current online doc gives the signature as int(x=0) int(x, base=10) where x is s string The 3.3.0 docstring says When converting a string, use the optional base. It is an error to supply a base when converting a non-string. One way to partially explain CPython's behavior is that when base is provided, the function behaves as if x defaults to '0' rather than 0. This is similar to the behavior of str(), which defaults to b'' when encoding or errors is provided, but otherwise defaults to '': http://docs.python.org/dev/library/stdtypes.html#str Certainly, accepting any object as a base, violating The allowed values are 0 and 2-36. just because giving a base is itself invalid is crazy. For further background (and you can see this is the 2.7 commit), int(base='foo') did raise TypeError in 2.7, but this particular case was relaxed in Python 3. --Chris ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] [Python-checkins] cpython (3.3): Issue #16045: add more unit tests for built-in int()
On 12/23/2012 4:47 PM, Chris Jerdonek wrote:
On Sun, Dec 23, 2012 at 12:03 PM, Terry Reedy tjre...@udel.edu wrote:
+# For example, PyPy 1.9.0 raised TypeError for these cases because it
+# expects x to be a string if base is given.
+@support.cpython_only
+def test_base_arg_with_no_x_arg(self):
+self.assertEquals(int(base=6), 0)
+# Even invalid bases don't raise an exception.
+self.assertEquals(int(base=1), 0)
+self.assertEquals(int(base=1000), 0)
+self.assertEquals(int(base='foo'), 0)
I think the above behavior is buggy and should be changed rather than frozen
into CPython with a test. According to the docs, PyPy does it right.
In any case, the discrepancy between doc and behavior is a bug and
should be fixed one way or the other way. Unlike int(), I do not see a
realistic use case for int(base=x) that would make it anything other
than a bug.
I support further discussion here. (I did draft the patch, but it was
a first version. I did not commit the patch.)
The current online doc gives the signature as
int(x=0)
int(x, base=10) where x is s string
The 3.3.0 docstring says
When converting a string, use the optional base. It is an error to supply
a base when converting a non-string.
One way to partially explain CPython's behavior is that when base is
provided, the function behaves as if x defaults to '0' rather than 0.
That explanation does not work. int('0', base = invalid) and int(x='0',
base=invalid) raise TypeError or ValueError. If providing a value
explicit changes behavior, then that value is not the default. To make
'0' really be the base-present default, the doc and above behavior
should be changed. Or, make '' the default and have int('',
base=whatever) return 0 instead of raising. (This would be the actual
parallel to the str case.)
This is similar to the behavior of str(), which defaults to b'' when
encoding or errors is provided, but otherwise defaults to '':
This is different. Providing b'' explicitly has no effect.
str(encoding=x, errors=y) and str(b'', encoding=x, errors=y) act the
same. If x or y is not a string, both raise TypeError. (Unlike int and
base.) A bad encoding string is ignored because the encoding lookup is
not done unless there is something to encode. (This is why the
ignore-base base-default should be '', not '0'.) A bad error
specification is (I believe) ignored for any error-free bytes/encoding
pair because, again, the lookup is only done when needed.
http://docs.python.org/dev/library/stdtypes.html#str
Certainly, accepting any object as a base, violating The allowed values are
0 and 2-36. just because giving a base is itself invalid is crazy.
For further background (and you can see this is the 2.7 commit),
int(base='foo') did raise TypeError in 2.7, but this particular case
was relaxed in Python 3.
Since the doc was not changed, that introduced a bug.
--
Terry Jan Reedy
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Re: [Python-Dev] [Python-checkins] cpython (3.3): Issue #16045: add more unit tests for built-in int()
On Sun, Dec 23, 2012 at 6:19 PM, Terry Reedy tjre...@udel.edu wrote:
On 12/23/2012 4:47 PM, Chris Jerdonek wrote:
On Sun, Dec 23, 2012 at 12:03 PM, Terry Reedy tjre...@udel.edu wrote:
+# For example, PyPy 1.9.0 raised TypeError for these cases because
it
+# expects x to be a string if base is given.
+@support.cpython_only
+def test_base_arg_with_no_x_arg(self):
+self.assertEquals(int(base=6), 0)
+# Even invalid bases don't raise an exception.
+self.assertEquals(int(base=1), 0)
+self.assertEquals(int(base=1000), 0)
+self.assertEquals(int(base='foo'), 0)
I think the above behavior is buggy and should be changed rather than
frozen
into CPython with a test. According to the docs, PyPy does it right.
In any case, the discrepancy between doc and behavior is a bug and should be
fixed one way or the other way. Unlike int(), I do not see a realistic use
case for int(base=x) that would make it anything other than a bug.
Just to be clear, I agree with you that something needs fixing (and
again, I did not commit the patch). But I want to clarify a couple of
your responses to my points.
One way to partially explain CPython's behavior is that when base is
provided, the function behaves as if x defaults to '0' rather than 0.
That explanation does not work. int('0', base = invalid) and int(x='0',
base=invalid) raise TypeError or ValueError.
I was referring to the behavioral discrepancy between CPython
returning 0 for int(base=valid) and the part of the docstring you
quoted which says, It is an error to supply a base when converting a
non-string. I wasn't justifying the case of int(base=invalid).
That's why I said partially explains. The int(base=valid) case is
covered by the following line of the CPython-specific test that was
committed (which in PyPy raises TypeError):
+self.assertEquals(int(base=6), 0)
If providing a value explicit
changes behavior, then that value is not the default. To make '0' really be
the base-present default, the doc and above behavior should be changed. Or,
make '' the default and have int('', base=whatever) return 0 instead of
raising. (This would be the actual parallel to the str case.)
This is similar to the behavior of str(), which defaults to b'' when
encoding or errors is provided, but otherwise defaults to '':
This is different. Providing b'' explicitly has no effect.
str(encoding=x, errors=y) and str(b'', encoding=x, errors=y) act the same.
If x or y is not a string, both raise TypeError. (Unlike int and base.) A
bad encoding string is ignored because the encoding lookup is not done
unless there is something to encode. (This is why the ignore-base
base-default should be '', not '0'.) A bad error specification is (I
believe) ignored for any error-free bytes/encoding pair because, again, the
lookup is only done when needed.
Again, I was referring to the valid case. My point was that str()'s
object argument defaults to '' when encoding or errors isn't given,
and otherwise defaults to b''. You can see that the object argument
defaults to '' in the simpler case here:
str(), str(object=''), str(object=b'')
('', '', b'')
But when the encoding argument is given the default is different (it is b''):
str(object='', encoding='utf-8')
TypeError: decoding str is not supported
str(encoding='utf-8'), str(object=b'', encoding='utf-8')
('', '')
But again, these are clarifications of my comments. I'm not
disagreeing with your larger point.
--Chris
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