I came across this issue while fixing issue20242. This issue (14031) still exists and is a major source of annoyance and confusion, and I suggest re-opening it.

Specifying the "{" style, while still being forced to use % formatting in log statements is backward and incredibly confusing for a number of key reasons:

 - The `style` keyword accomplishes a single thing only, and that is changing the format specification of the output, which is specified once and never touched again. For the myriad log statements littered throughout a codebase, it has *absolutely* no effect.
 - This is incredibly misleading to users. Why would there be this parameter to basicConfig that does (next to) nothing? Furthermore, if I've specified the { style, **why** would I write my log statements using the % style.
 - It forces the user to keep using % style formatting. The documentation explicitly states that this is "old style" formatting, and "new style" should be used, (due to its many advantages). Why force the user to know two formatting styles?


I created a patch (with test cases) that allows for this functionality. The whole idea of this feature is giving users the choice, if their environment allows it, to use the new-style formatting. Users should not have to rely on the hack linked in the blog in order to achieve *exected* behavior!