Issue 1749: Review view occasionally does not load diff and only displays header and footer
Status:  Submitted
Owner: ----
Closed:  May 2013
Reported by andreas....@googlemail.com, Jan 8, 2013
Affected Version: Gerrit 2.5.1 (but already occurred in 2.5.0 as well)

What steps will reproduce the problem?
1. Go to a Change.
2. Click on a file (or on "Side-by-Side" for that file) that is part of a patch set.

What is the expected output?
(Side-by-side) diff is displayed.

What do you see instead?
Header bar and footer loads, "Working..." flashes up for a brief period of time, disappears, but the diff is not displayed. Only the green header (with all its contents) and the footer ("Press ...", Gerrit version, etc.) is shown.

Repeatedly force-reloading (shift + reload) usually convinces Gerrit to display the diff after a couple of tries (varies between 1 and 10 or more, usually around 5 reloads are necessary).

Seems to happen more often with bigger patch sets (where big == ~50 changed files).

Please provide any additional information below.
Using Firebug, I see that all network requests succeeded successfully (200 OK for all of them), but in the Console, I see:

TypeError: a is null
http://<omitted from defect report>/gerrit/80B6F7522877AC0C7F68634B94AC6712.cache.html
Line 3132
...null){d=a.D.e.rows.length;for(e=0;e<d;++e){c=WLc(a.D.f,e,0)[$gd];if(c!=null&&Wl(...

Browser: Firefox 18.0b7 (but already experienced in at least Firefox 17).

Interestingly enough, force-reloading almost never gets the diff to load while Firebug is enabled, after switching Firebug off, it loads after a couple of more force-reloads. I can still observe the same error message in the regular Firefox Error Console though for the failed loads with Firebug disabled. Perhaps this points to a timeout that is too short, with Firebug slowing execution down enough such that the timeout is always hit, as opposed to regular operation, where the timeout is only hit occasionally?
May 14, 2013
#1 nemow...@gmail.com
Example URL: https://gerrit.wikimedia.org/r/#/c/63290/3/api/ApiTranslateSandbox.php (gerrit 2.6-rc0-328-g72b7141).

I got the same error as bug reporter on Firefox 20.0 and "Uncaught TypeError: Cannot read property 'L' of null" on Chromium 25.0.1364.172.

May 16, 2013
#2 sop@google.com
(No comment was entered for this change.)
Status: Submitted
Labels: FixedIn-2.6