Invalid format string %04Y on Windows

Invalid format string when using %04Y on Windows 10 Python 3.7.1

$ python
>>> from datetime import datetime
>>> datetime(90, 1, 1).strftime("%04Y")
ValueError: Invalid format string
>>> datetime.strptime("2018-10-31 22:29:29.553000", "%Y-%m-%d %H:%M:%S.%f").strftime("%04Y-%m-%dT%H:%M:%S.%fZ")
ValueError: Invalid format string

Some platforms support modifiers from POSIX 2008 (and others). On Linux the format “%04Y” assures a minimum of four characters and zero-padding. The internal code (as used on Windows and by default on macOS) uses zero-padding by default

https://www.rdocumentation.org/packages/base/versions/3.5.1/topics/strptime#l_sections

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Related issues

• https://github.com/singer-io/singer-python/issues/81
• %04Y introduced in https://github.com/singer-io/singer-python/pull/52
• macOS support added in https://github.com/singer-io/singer-python/pull/69

[timvisher]

Pushed 5.3.3 to PyPI. Thanks! 😃

[timvisher]

Ah. Got it. 😃

So we’d definitely accept patches to improve Windows support but I’ll let you know up front that the testing burden might be a little high, since none of us have easy access to Windows machines at the moment nor any expertise on developing/debugging Python on Windows issues.

I guess at a minimum we’ll want to see some unit tests added if they don’t already exist that test that 3 digit years are zero padded without %04D on Windows and that they continue to be padded on Mac/Linux.

In terms of the general design I don’t think duck typing is necessarily the wrong way to go here. First try with the Mac/Linux format string, fall back to the windows format string on an exception, otherwise raise.

Sound good?