[calsify] AD Evaluation: draft-ietf-calext-ical-tasks-11

[Orie <[e-mail]>]

# Orie Steele, ART AD, comments for draft-ietf-calext-ical-tasks-11
CC @OR13

* line numbers:
  -
https://author-tools.ietf.org/api/idnits?url=https://www.ietf.org/archive/id/draft-ietf-calext-ical-tasks-11.txt&submitcheck=True

* comment syntax:
  - https://github.com/mnot/ietf-comments/blob/main/format.md

## Comments

Love the diagram in Figure 1.

### Augmented Status definition

```
938   Format Definition  The "STATUS" property parameter list is augmented
939      as follows:

941   statvalue-todo = / "PENDING"    ;Indicates a to-do has been
942                                   ;created and accepted, but has
943                                   ; not yet started.
944                   / "FAILED"      ;Indicates to-do has failed.
```

Title of the section says redefined, but the body of the section only has
the additions.
I would prefer to see a completely updated ABNF here, or at least the
existing definitions, since they are not being destroyed by this update.

I didn't check all the ABNF, but if you feel that this applies to other
sections, I would consider making it clear where you are "overwriting" and
where you are  "extending".

### Why not MUST?

```
493   A task that has intermediary deadlines (i.e., milestones) SHOULD be
494   expressed by child "VTODO" calendar components (i.e., sub-tasks
495   associated with each of the milestones) in conjunction with the
496   "RELATED-TO" property to relate the parent and child tasks.
```

Are there any obvious cases where this SHOULD ought to be strengthened or
weakened?

### Why not MUST?

```
1040   The server SHOULD return an HTTP 403 response with a DAV:error
1041   element containing a CALDAV:supported-task-mode XML element, if a
1042   client attempts to store iCalendar data with an "TASK-MODE" element
1043   value not supported by the server.
```


### SHOULD fail gracefully?

```
1045   It is possible for a "TASK-MODE" value to be present in calendar data
1046   on the server being accessed by a client that does not support the
1047   "TASK-MODE" property.  It is expected that existing clients, unaware
1048   of "TASK-MODE", will fail gracefully by ignoring the calendar
1049   property.
```

## Nits

### poor relation is a bit casual

```
13   The Internet Calendaring and Scheduling Core Object Specification
14   (iCalendar) (RFC5545) VTODO calendar component has been seen as the
15   poor relation of VEVENT - useful only for personal reminders and to-
16   do lists.
```

### "DUE"/"DURATION"

```
708      completed.  When present, "DTSTART" and "DUE"/"DURATION"
709      properties represent the window in which the task can be
710      performed.  The "ESTIMATED-DURATION" property SHOULD be passed
```

I know what you mean here, but the / is perhaps not as clear as a rewording.