Choices longer than 1 day don't work with DurationField

[zauddelig]

When one tries to use DurationField with choices and a time span longer than a day the field will always raise a ValidationError.

choices = (timedelta(days=7), "one week")

The problem is in the to_python method wich calls django.utils.dateparse.parse_duration this methond use the following regex:

standard_duration_re = re.compile(
    r'^'
    r'(?:(?P<days>-?\d+) )?'
    r'((?:(?P<hours>\d+):)(?=\d+:\d+))?'
    r'(?:(?P<minutes>\d+):)?'
    r'(?P<seconds>\d+)'
    r'(?:\.(?P<microseconds>\d{1,6})\d{0,6})?'
    r'$'
)

But is not standard in the view that we are using timedelta objects, whose default rapresentation is : %d days, %h:%m:%s. So I propose to change the regex in with the following:

 standard_duration_re = re.compile(
    r'^'
    r'(?:(?P<days>-?\d+) (days, )?)?'
    r'((?:(?P<hours>\d+):)(?=\d+:\d+))?'
    r'(?:(?P<minutes>\d+):)?'
    r'(?P<seconds>\d+)'
    r'(?:\.(?P<microseconds>\d{1,6})\d{0,6})?'
    r'$'
)

[zauddelig]

EDIT:
I was thinking that this:

choices = (format(timedelta(days=7)).replace("days, ",""), "one week")

would've work but it get blocked at Field.validation level, at that time the value is already checked against a timedelta

[Tim Graham <timograham@…>]

In 262d4db8:

Fixed #24897 -- Allowed using choices longer than 1 day with DurationField

[Tim Graham <timograham@…>]

In 7f92b6e:

[1.8.x] Fixed #24897 -- Allowed using choices longer than 1 day with DurationField

Backport of 262d4db8c4c849b0fdd84550fb96472446cf90df from master