826382 - When I accessed lowWaterArticleNum of a nsIMsgDatabase object, exception occurred. Why? [Exception... "Component returned failure code: 0x80004001 (NS_ERROR_NOT_IMPLEMENTED) [nsIMsgDatabase.lowWaterArticleNum]" nsresult: "0x80004001 (NS_ERROR_NOT_IMPLEME

Status: RESOLVED WONTFIX

(MailNews Core :: Backend, defect)

Description

[WADA:World Anti-bad-Duping Agency]

When I accessed lowWaterArticleNum of a nsIMsgDatabase object, exception occurred. Why? 

When I simply accessed lowWaterArticleNum property of a nsIMsgDatabase object, following exception occurred.
Why? Is it design?
How can I avoid such exception when I simply refer the lowWaterArticleNum property of a nsIMsgDatabase object, which is actually returned as an property of a nsIMsgFolder object? 

[Exception... "Component returned failure code: 0x80004001 (NS_ERROR_NOT_IMPLEMENTED) [nsIMsgDatabase.lowWaterArticleNum]"  nsresult: "0x80004001 (NS_ERROR_NOT_IMPLEMENTED)"

Note-1:
Exception occurred in both Tb 17.0.1 and Tb truk(Tb 20.0a1 2012/12/18 build).
Note-2:
Access of highWaterArticleNum property of the nsIMsgDatabase has no problem(value of 77049 was returned).

Comment 1

[WADA:World Anti-bad-Duping Agency]

Above exception occured in following code for checking property value.
  for(var prop in An_object){ var text = prop + "=" + An_object[prop] ; ... }
This exception can easily be caught by try/catch.
  try      { var text = prop + "=" + An_object[prop] ;  }
  catch(e) { var text = prop + "=" + "(Exception)" + e; }
Because purpose is checking all property's value for trouble shooting, there is no need to use highWaterArticleNum. So, practically no problem occurs by the exception.

Comment 2

[Mark Banner (:standard8)]

If you do a quick search in mxr:

http://mxr.mozilla.org/comm-central/search?string=lowWaterArticleNum

and take a quick look at the implementations, you'll see that lowWaterArticleNum is not implemented (as the error suggests) for general message databases, but it is for news messages.

This is just how the interfaces are defined and implemented, and I don't think there's anything worth changing here.