bug#20832: 25.0.50; todo-show accidentally deleted my todo file.

[martin rudalics]

>>       When writing an application, you should normally use the
>>       higher-level functions described in *Note Switching Buffers::,
>>       instead of calling `set-window-buffer' directly.
>
> Is this a change from previous policy?  In earlier versions of
> todo-mode.el I had several instances of switch-to-buffer, but some time
> ago replaced them with set-window-buffer and I'm pretty sure I did that
> because I was given to understand that programmatic use of
> switch-to-buffer was discouraged.  If this is no longer the case (or if
> I was mistaken back then), I'll have check (when I have time) all of the
> uses of set-window-buffer in todo-mode.el for unanticipated side
> effects.

Nothing has changed.  The term "normally" stands more or less for "when
you use ‘set-window-buffer’ you are supposed to know what you do".  This
is a low level function and should be allowed to set the buffer of any
window (like the minibuffer or a tooltip window) just as ‘window-buffer’
returns the buffer shown in any live window.

OTOH I don't recall any restrictions on using ‘switch-to-buffer’
programmatically.  Just that you should _not_ expect it to always use
the selected window.

martin