Threaded comments for ticket change history

[cboos]

I was sure there was already a ticket for that… apparently not.

Anyway, the idea is not new. For tickets with a long and complicated history, a simple linear view of the change history can be difficult to follow. We have the follow-up/in reply to links, but that doesn't give an immediate visual representation of the structure, one has to click and follow the links.

Fortunately that "follow-up" information is all we need to re-organize the comments in a tree, using Javascript. The proposed UI for that is a "Threaded Comments" checkbox next to the Change History section.

When activated, changes are displayed like this:

[cboos]

illustrates threaded-comments-r10450.patch​

[cboos]

ticket: threaded mode for change history.

[cboos]

Patch applied in [10510] (also, there I don't show the button if there's nothing to "thread").

It may be that one things or two remains to be improved, in which case we can add some notes here.

Also, an extension of this feature could be done in order to implement #3360.

[cboos]

Already noticed a few glitches:

• the "inreply.png" arrow is also added to li.entry elements of embedded patches; apparently the CSS rule ul.children > li matches also for li entries not immediate children of ul.children, which I didn't expect from my limited understanding of CSS
• the left border could be improved (e.g. 1px solid #eee)
• the indent of the <li> elements could be a bit narrower ⇒ not found how to do it yet

As a side note:

Also, I've got trouble testing this at all in IE9, as an exception was thrown earlier from resizer.js:

var grip = $('<div class="trac-grip"/>').mousedown(beginDrag)[0];

(Object doesn't support this property or method thrown later in clone() in jquery.js - maybe a problem due to the recent switch to jQuery 1.5?). Hm. Actually there are lots of other problems with IE9. Strange, I didn't notice this when testing 1.5rc1. Right, this is ​http://bugs.jquery.com/ticket/8052.

[cboos]

… a few glitches:

All of these should be addressed in the follow-up changeset r10516.