266893 - Deleted RSS .MSF file -> No further read from feeds

Status: RESOLVED FIXED

(MailNews Core :: Feed Reader, defect)

Description

[Mike Cowperthwaite]

It seems that if the .MSF file for a feed is deleted, altho the file will get 
rebuilt, there will be no further reads from the feed, at startup or by manually 
requesting Get New Messages.

I'm seeing this in TB 0.8 and nightlies.

To reproduce:
1) set up an RSS account in TB
2) add a feed (find an active one if you can, makes it easier to test)
3) fetch all the current messages; mark them all read (or delete them)
4) exit TB
5) locate the directory for the account and delete the feed's .MSF file
6) after waiting a reasonable while, go to the feed & try to get new messages

Actual results:
nuthin'!

Expected results:
New items are retrieved.

Note that a new .MSF file *is* created.  The contents are quite different, tho.

Comment 1

[Mike Cowperthwaite]

Attachment: Original .msf

Comment 2

[Mike Cowperthwaite]

Attachment: Rebuilt .MSF

The two attachments were created from the feed
  http://www.deftone.com/blogzilla/atom.xml

Comment 3

[sairuh (rarely reading bugmail)]

I think I might've encountered this while clearing out .msf files from various
accounts, including my RSS one. but am not sure --I encountered this issue
around the same time I had renamed my RSS account (via Account Central panel).
so I'll need to see which scenario actually caused the non-refreshing of feeds.

cc'ing marcia, trix, david and asa in case they've encountered or heard of
similar issues.

Comment 4

[sairuh (rarely reading bugmail)]

okay, it wasn't renaming the RSS account: getting new articles still works after
doing that.

Comment 5

[sairuh (rarely reading bugmail)]

yeah, I encounter this bug after removing the summary file for an RSS feed.

nominating: I know the advice might be "don't do that!" but I think fixing this
would make this feature more robust.

but if we do minus this, then a relnote suggestion: If you do remove the .msf
for an RSS feed, you won't be able get new articles. A semi-workaround would be
to delete the feed, then re-add it --from the GUI rather than going through your
profile folder files.

Comment 6

[Scott MacGregor]

all of the feed information is stored in the summary file. If you delete the msf
file then we will lose all of this information. That's where we store it.

That's like saying "if you delete the database you should still remember what I
put in the database" :)

I'm not sure we'll be fixing this unless David feels otherwise. 

Comment 7

[Mike Cowperthwaite]

(In reply to comment #6)
> all of the feed information is stored in the summary file. If you delete the
> msf file then we will lose all of this information. That's where we store it.

Not *all* of the information is in there, clearly; the subscription name, URL 
and target folder are all still available in the Manage Subscriptions dialog; 
and I thought that the "which articles have I already aggregated" list is stored 
in the .RDF files.

Buf if there is some critical and un-recoverable data there, then what is the 
point of rebuilding the file?  If the program starts up and discovers the MSF is 
missing, it should say, SORRY, DATABASE CORRUPT, not rebuild a corrupt MSF file 
and then fail silently.  Ideally, since the sub information is apparently still 
there, it should ask if I want to resubscribe.

Comment 8

[David :Bienvenu]

Scott, I think we should probably try to do something like we do for virtual
folders, which is to store the information in a global place, and in the .msf
file, so that we can rebuild the .msf file if we need to. I feel bad because I
think I led us down the path we're on...but I found out the hard way with
virtual folders that people do delete the .msf files...

Comment 9

[David :Bienvenu]

Attachment: proposed fix

Many thx to Scott for the RDF-fu. This fix checks if the url is null for a
folder, and if so, recreates it from the subscriptions ds, and then resets it
in the db.

Comment 10

[David :Bienvenu]

Comment on attachment 166944 [details] [diff] [review]
proposed fix

ignore the part about passing in null for the msg window - that's an
experiment...

Comment 11

[Mike Cowperthwaite]

This patch appeared to fix my problem; all the old feeds that I'd never resub'd 
to immediately fetched new items when I started TB 0.9+1126.