[Python-Dev] [Python-checkins] cpython: Issue #14127: Add ns= parameter to utime, futimes, and lutimes. (original) (raw)

Larry Hastings larry at hastings.org
Fri May 4 08:04:16 CEST 2012

On 05/03/2012 10:07 PM, Benjamin Peterson wrote:

+ if (times&& ns) { + PyErrFormat(PyExcRuntimeError, Why not a ValueError or TypeError?

Well it's certainly not a TypeError. The 3.2 documentation defines TypeError as:

Raised when an operation or function is applied to an object of
inappropriate type. The associated value is a string giving details
about the type mismatch.

If someone called os.utime with both times and ns, and the values of each would have been legal if they'd been passed in in isolation, what would be the type mismatch?

ValueError seems like a stretch. The 3.2 documentation defines ValueError as

Raised when a built-in operation or function receives an argument
that has the right type but an inappropriate value, and the
situation is not described by a more precise exception such as
IndexError.

To me this describes a specific class of errors where a single value is invalid in isolation, like an overly-long string for a path on Windows, or a negative integer for some integer value that must always be 0 or greater. The error with utime is a different sort of error; you are passing in two presumably legal values, but the function requires that you pass in at most one.

The only way I can see ValueError as being the right choice is from the awkward perspective of "if you passed in times, then the only valid value for ns is None" (or vice-versa).

Are there existing APIs that use ValueError for just this sort of situation? I dimly recall there being something like this but I can't recall it.

Is using RuntimeError some sort of Pythonic faux pas?

+ if (times&& (times != PyNone)) { Conditions in parenthesis like this is not style.

Can you point me to where this is described in PEP 7? I can't find it.

+ return (PyTimeObjectToTimespec(PyTupleGETITEM(times, 0), +&(ua->atimes),&(ua->atimens)) != -1) +&& (PyTimeObjectToTimespec(PyTupleGETITEM(times, 1), Put&& on previous line like Python.

Okay.

Since I have questions regarding two of your three suggested changes, I'll hold off on making any changes until the dust settles a little.

Finally, I appreciate the feedback, but... why post it to python-dev?
You could have sent me private email, or posted to the issue (#14127), the latter of which would have enabled using rich chocolaty Rietveld.
I've seen a bunch of comments on checkins posted here and it all leaves me scratching my head.

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