531128 - Session restore creates a blank tab titled "Loading..." for invalid URLs that were valid in previous session

Status: RESOLVED FIXED

(Firefox :: Session Restore, defect)

Description

[Daniel Holbert [:dholbert]]

STR:
 1. Install Jetpack: https://addons.mozilla.org/en-US/firefox/addon/12025
 2. Restart Firefox
 3. Open one tab at about:jetpack, and another at any URL (e.g. about:blank)
      (The second tab is just for triggering a session restore prompt)
 4. In Add-ons manager, disable Jetpack.
 5. Restart Firefox. When prompted if you want to save your tabs, choose "yes".

ACTUAL RESULTS:
When Firefox starts up next:
 - I get an alert message saying "The URL is not valid and cannot be loaded."
 - The tab that was at "about:jetpack" is now blank, and its title is "Loading...", with no favicon.  (though nothing ever loads)
 - If I restart Firefox again (without closing this tab), the same thing happens in my next Firefox session (and every session thereafter, until I close the tab).

EXPECTED RESULTS:
 - Ideally, no alert should be shown (though perhaps that's ok on the first session restore after the addon-disabling)
 - The tab header should show "(Untitled)" (like an about:blank tab), instead of "Loading...".
 - OR, the invalid tab could just be excluded from restoration altogether.

Comment 1

[Daniel Holbert [:dholbert]]

SECOND EXPERIMENT:
Instead of "about:jetpack" in step 3, use this URL:
   chrome://jetpack/content/NONEXISTENT_PAGE.html
Note that (when Jetpack is enabled) this gives you a "File not found" page, with a warning favicon.

As before, disable Jetpack & restart Firefox, with this tab open.

ACTUAL RESULTS FOR SECOND EXPERIMENT:
 - No alert is shown (presumably because the URL is valid)
 - However, I still get a blank tab titled "Loading...", this time with a warning favicon (moz-icon://stock/gtk-dialog-warning?size=16) -- the same favicon that was used Jetpack was enabled.

Comment 2

[Daniel Holbert [:dholbert]]

Note: In both experiments (comment 0 & comment 1), Firefox's Location Bar is blank for the restored invalid tab.

Comment 3

[Daniel Holbert [:dholbert]]

I've reproduced this bug in both mozilla-central trunk & Firefox 3.5.5.

Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.3a1pre) Gecko/20091125 Minefield/3.7a1pre
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5

Comment 4

[Daniel Holbert [:dholbert]]

One other way to reproduce this bug:
 - Close the "soon-to-be-invalid" tab before restarting Firefox (making sure to save your session).
 - After the restart, use Ctrl-Shift-T (or use History | Recently Closed Tabs) to resurrect the tab.
  --> BUG (same actual results as in comment 0 / comment 1)

ALSO: Once you've reproduced the bug, you can trigger it over & over, without restarting, by simply closing the "buggy" tab and then resurrecting it with Ctrl-Shift-T.

Comment 5

[Tim Taubert [:ttaubert] (inactive)]

The tab title is nowadays "Problem loading page" and instead of an annoying popup we luckily have about:neterror that shows a page with a "try again" button. Let's consider this fixed.