[BUG] Regex for xs:dateTime does not properly support timezones

[mjacoby]

Describe the bug
The regex for values of type xs:dateType

^-?(([1-9][0-9][0-9][0-9]+)|(0[0-9][0-9][0-9]))-((0[1-9])|(1[0-2]))-((0[1-9])|([12][0-9])|(3[01]))T(((([01][0-9])|(2[0-3])):[0-5][0-9]:([0-5][0-9])(\\.[0-9]+)?)|24:00:00(\\.0+)?)(Z|\\+00:00|-00:00)

does only allow Z, +00:00, or -00:00 as timezones.
Correct behavior would be to allow Z or any other timezone of format (+|-)[0-9]{2}:[0-9]{2}.

Where

• aas-specs/schemas/json/aas.json

  Line 224 in 04a1f04

  "pattern": "^-?(([1-9][0-9][0-9][0-9]+)|(0[0-9][0-9][0-9]))-((0[1-9])|(1[0-2]))-((0[1-9])|([12][0-9])|(3[01]))T(((([01][0-9])|(2[0-3])):[0-5][0-9]:([0-5][0-9])(\\.[0-9]+)?)|24:00:00(\\.0+)?)(Z|\\+00:00|-00:00)$"

• aas-specs/schemas/json/aas.json

  Line 622 in 04a1f04

  "pattern": "^-?(([1-9][0-9][0-9][0-9]+)|(0[0-9][0-9][0-9]))-((0[1-9])|(1[0-2]))-((0[1-9])|([12][0-9])|(3[01]))T(((([01][0-9])|(2[0-3])):[0-5][0-9]:([0-5][0-9])(\\.[0-9]+)?)|24:00:00(\\.0+)?)(Z|\\+00:00|-00:00)$"

Additional context
https://www.w3.org/TR/xmlschema-2/#dateTime Section 3.2.7.3

[mjacoby]

This is actually more complex as I described in aas-core-works/aas-core-meta#355 (comment)

Copying my response from there

The specification says the following for basicEventElement.lastUpdate

The issue here is that the Type is dateTime which is defined as xs:dateTime, meaning it can have any timezone. However, the explanation column states that the timestamp should/must(?) be in UTC. Based on that you introduced a new "type" Date_time_UTC. I would argue that the specification is wrong or at least inconsistent as the type information is constrained by the explanation to an undefined type "dateTimeUTC". The correct way to handle this would be to change the specification to either defined the type dateTimeUTC or to remove the UTC restriction in the explanation.

[s-heppner]

I imagine to remember that there was once a decision that the timestamps must all be defined in UTC, but maybe @BirgitBoss could clarify this?