Incorrect format of acq_time column

[mateuszpawlik]

I get the following warning. The format seems to be correct according to https://bids-specification.readthedocs.io/en/stable/common-principles.html#units YYYY-MM-DDThh:mm:ss[.000000][Z]

[WARNING] TSV_VALUE_INCORRECT_TYPE_NONREQUIRED A value in a column did match the acceptable type for that column headers specified format.
		acq_time
		/sub-01/ses-01/sub-01_ses-01_scans.tsv - '2022-12-16T14:44:43.955625Z'

[mateuszpawlik]

FYI @barbarastrasser

[effigies]

This is bids-standard/bids-specification#1968 and needs to be fixed in the schema.

[mateuszpawlik]

The validator actually listed two entries:

/sub-01/ses-01/sub-01_ses-01_scans.tsv - '2022-12-16T14:44:43.955625Z'
/sub-02/ses-01/sub-02_ses-01_scans.tsv - '2022-12-07T09:36:08.944089Z'

I missed that before, but could the warning be because of:

No specific precision is required for fractional seconds, but the precision SHOULD be consistent across the dataset.

[effigies]

No, the problem is actually the Z. The specification permits Z, but when it was coded up in the schema, the regex says [A-Z]{2,4} to accept timezone codes. This was a mistake, as that's not ISO8601 compatible.

We intended to adopt a subset of RFC3339 that let you use local time or UTC and not permit offsets at all, but the above-linked issue convinced me that there are good reasons to permit people to use local offsets.

I'm opening a PR to adopt RFC3339 fully.