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micropython / micropython-lib

Core Python libraries ported to MicroPython
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ntptime: Year 2036 fix. #830

Closed jonfoster closed 3 months ago

jonfoster commented 3 months ago

Fix a bug in the NTP client, where it would report the wrong time after 7 Feb 2036.

The NTP timestamp has a 32-bit count of seconds, which will wrap back to zero on 7 Feb 2036 at 06:28:16.

It's now March 2024. So we know that timestamps less than 1st Jan 2024 are impossible. So if the timestamp appears to be earlier than 1st Jan 2024, that probably means that the NTP time wrapped at 2^32 seconds. (Or someone set the wrong time on their NTP server, but we can't really do anything about that). So in that case, we need to add in those extra 2^32 seconds, to get the correct timestamp.

This means that this code will work until the year 2160.

(More precisely, this code will not work after 7th Feb 2160 at 06:28:15. Fixing that is someone else's problem, some time in the far future, by adjusting the NTP_DELTA and MIN_NTP_TIMESTAMP values. By just changing those two numbers, you can choose any 136-year span of time that will be supported).

jonfoster commented 3 months ago

Commit message fixed to comply with the coding standards. (I hope).

jonfoster commented 3 months ago

Sorry, I didn't intend for all those WIP commits to go into this PR. Will try to sort that out.

jonfoster commented 3 months ago

Moved to https://github.com/micropython/micropython-lib/pull/837