Wiki history empty if end revision precedes start revision

[luca.ceresoli@…]

How To Reproduce:

1. go to http://trac.edgewall.org/wiki/WikiStart?action=history
2. in the first radiobutton column click on, say, version 130
3. in the second radiobutton column click on, say, version 128
4. Click the "View Changes" button
5. Note that the resulting page shows differences between Version 128 and Version 128. Version 130 has been completely neglected.

System Information:
Just verified on trac.edgewall.org (currently running 0.12dev-r9164).

What it should do instead? Not sure:

• show differences between 128 and 130 (i.e. swap versions so that they are correctly ordered), or
• show backwards differences, or
• anything else?

[cboos]

Replying to luca.ceresoli@…:

What it should do instead? Not sure:

• show backwards differences,

+ make it clear it's a reverse diff, as reverse diffs for wiki changes is not a common feature. But I'm not in favor of preventing the feature, like MediaWiki does.