1266005 - No error modifying calendar with read-only permissions with offline support switched on

Status: NEW

(Calendar :: Provider: CalDAV, defect)

Description

[Daniel]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0
Build ID: 20160304114926

Steps to reproduce:

On Server: Zimbra 8.6.0_GA_1191.NETWORK
Clients tested: 
1. Win7 64bit -  Thunderbird 38.6.0, Lightning 4.0.6
2. Ubuntu 14.04 TLS 64bit - Thunderbird 38.6.0, Lightning 4.0.5.2

Issue:
1. I have a calendar which my account has read-only permissions for.
2. Calendar can be integrated into Lightning using CalDAV and is displayed correctly.
3. "Offline Support" is switched on.
4. "Read only" is switched off.
5. Refresh Calendar set to "Every minute".
6. I can modify any appointment in the calendar, as if I have writing permissions.

You can switch on the "read only" mode and the issue does not appear, but there are cases where people are not aware of their permissions with certain calendars.


Actual results:

1. The calendar allowed me to modify the existing appointments (e.g. moving one appointment to another timeslot) without giving any indication that this is not allowed on the server side. 
2. There is no error even after waiting the "one minute" until the calendar refreshes itself/synchronizes with the server.
3. No error after manually clicking on the Synchronize button.
4. After some seemingly random (varying) period of time there is a message telling that an error occurred when writing to the calendar. But this takes so long that the user could have closed the client already - even after clicking on "Synchronize" - without noticing that his work (e.g. a newly created appointment) is lost.
5. The changes are lost after opening Thunderbird at a later time.
6. All of this does not happen when "Offline Support" is switched off, the error is coming up immediately.


Expected results:

Best case:
1. Client tests for the given permissions and configures the calendar to "read only" if necessary.

At least:
1. If "Offline Support" is switched on and there actually is a connection to the server, the user should be informed that his actions are not valid.
2. If "Offline Support" is switched on and there is no connection to the server, the users work should be saved locally and not be overwritten on the next startup of Thunderbird. Instead there should be an option to move the changes to another calendar temporarly, giving the user the possibility to clear the misunderstanding and move the appointments accordingly.

Comment 1

[[:MakeMyDay]]

This is a known long standing issue, but I cannot find the according bug report atm, so I leave this bug open to track the issue. Bug 462859 is related but emphasis on modifying the permissions instead of respecting them, what's the subject here. If someone finds the bug which is already tracking this, feel free to dupe this one.

The workaround for this is to make the respective calendar read-only manually, as you already noticed.