On the way to Zope 4, the biggest change was DateTime >= 3, which has these main differences:

 - `DateTime` instances are new style classes
 - `DateTime.__eq__` now take into the timezone into account
 - `DateTime` supports timezone naive ( https://docs.python.org/3/library/datetime.html#aware-and-naive-objects ) - actually this is since DateTime 2.12 , but since we fully patched the method where the parsing happens, ERP5's patched DateTime never used timezone naive dates.
 - pickles are also different.

These are changes to prepare ERP5 code base to support DateTime >= 3, while keeping compatibility with the previous behavior, this means that we keep patching to keep the same behavior as DateTime 2, so that `DateTime.__eq__` ignores timezone difference and `DateTime` does not support timezone naive dates - these two different behavior seemed to introduce too much breakages, especially in project code, with no immediate benefit for our usages. For now, while ERP5 is still based on Zope 2 / DateTime 2 the fact that DateTime are new style classes has no impact, this will only impact once we switch to Zope 4.

This also change the code to adjust the part where we were depending on implementation details of DateTime and where the details changed on DateTime 3, sometimes exposing higher level API, like the new `timeZoneContext` to use in tests.



See merge request nexedi/erp5!1593

See merge request !1725

See merge request nexedi/erp5!1726

use calendar module and public DateTime API instead.

This ensures that we don't break more.

We have code depending on these attributes, they were used in pattern
like this:

```py
try:
  DateTime(user_input)
except DateTime.DateError:
  error("invalid date")
```

so it's safer to keep the attributes for now, since we are already
patching a lot

We have too much code depending on this behavior, so we keep this patch
for now.

By using iso format we create dates in UTC timezone

This is a context manager which temporary allow to change the time zone.

It is not thread safe and intended to be used in tests only, to replace
setTimeZoneToUTC and setTimezone methods by something unified which
makes the transition to DateTime 4 easier, because changing timezone
was done by patching private attributes and the DateTime 4 use different
attributes.

Use calendar module instead. These API depends on current locale, but
we don't set the locale in ERP5, so these remain in English

This is just hiding problem and does not seem needed.

See merge request nexedi/erp5!1723

The changes from ae15e7e1 (accounting: show the context when
showing invalid bank accounts, 2022-12-21) were a regression because
with the previous behaviour, by just looking at the transactions,
users could see with the ??? that something was wrong with the bank
account. After these changes they had to open the select element.

This restore somehow the previous behaviour by displaying the label
with ??? marker, but since we have the label, we display the
label (bank account reference) instead of the value (the relative URL)

This was working only with Organisations

Fix small problems displaying bank accounts on accounting transactions and be more strict during validation:
 - bank account must be validated
 - bank account must belong to the section

The latter was a problem for scenarios like this:
 - create transaction for supplier 1 with supplier 1 bank account
 - clone transaction
 - change to supplier 2
the bank account remains as supplier 1 bank account, although it became an invoice from supplier 2.
The transaction could be validated as long as the bank account is not invalidated

See merge request nexedi/erp5!1713

See https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script/type

The only check with accounting transactions regarding bank account
was that the bank account is not invalidated. This makes the
constraint more strict by checking that the bank account belongs to
the corresponding entity and also that the bank account is validated.

A few tests needed to be updated to validate the bank accounts. Also
a legacy sequence test has been removed because it is now covered by
normal tests.

The parameter is still named `organisation` for "API stability", but
this parameter can be a person.

This was already used by the fields on accounting transaction for
source/destination_payment and more or less working already, except
for the case where the person had a subordination to an organisation
member of the group, in that case instead of showing the bank accounts
from the person this was showing the bank accounts from the
organisation

On a transaction without section / mirror section, on the profile tab
all accouts where displayed

drop skip_invalidated_bank_accounts option, we are now using
base_category instead.

erp5_accounting, erp5_payment_mean: display currently selected Bank Account even if it is invalidated.

no need to validate them in the test

We had nexedi/erp5@a6b588e7 but this was only solving the case of a trailing ;

See merge request nexedi/erp5!1710

See 0c2dd107