snap.refresh.hold incompatibility with output from 'date' utility

[Andrew Garrett]

The snap documentation on the snap.refresh.hold <https://snapcraft.io/docs/keeping-snaps-up-to-date#heading--refresh-hold> configuration parameter has a note that "We explicitly format the date command output because the version of date provided by GNU core utilities breaks RFC3339 compatibility when passing the --rfc-3339 argument. See the bug report for further details.".

When you follow the "bug report", it appears that somebody back in 2006 has told the coreutils team that RFC3339 requires the use of a 'T' to separate the dates and times, and it appears that the coreutils team disagrees with this assessment.

I have no idea what the correct interpretation is of RFC3339, but this comes across as refusing to parse the format emitted by a very common utility out of sheer pettiness.

As a user 17 years down the track with very little interest in the particularities of RFC3339, there is no reason why I should have to care for one second about a disagreement with the gnu-coreutils team about the correct interpretation of a standards document, and certainly no reason why I should have to laboriously type out the 'correct' date format.

snapd should gracefully handle the date format emitted by the 'date' utility with the --rfc-3339 flag, regardless of anyone's beliefs about whether or not it's correct. 17 years later, the format is very unlikely to change.

Regardless of whether you change the behaviour, the 'tip' in the documentation is honestly embarrassing and I'd suggest rewording it either way - the link to the bug report makes the maintainers of snapd look petty and stubborn rather than clever.

[Graham Morrison (morrisong)]

Hello - thanks for commenting on this, and I totally agree. I've removed the admonition entirely.