Re: minibuffer-selected-buffer

[Richard Stallman]

    The function minibuffer-selected-window returns the window which was
    selected when entering the minibuffer. For bibtex.el I would like to
    use a function minibuffer-selected-buffer that returns the buffer
    which was the current buffer when entering the minibuffer. Would it
    make sense to add such a function to emacs?

The best practice is to call completing-read only to read arguments
to a command.  The current buffer when the command is run
is the selected window's buffer.

So it seems that (window-buffer (minibuffer-selected-window)) would do
the job.  In what case is this not correct?