A dynamic and adaptive function used by `ivy-posframe-size-function'

ivy-posframe-get-size.el

(ivy-posframe-size-function
 (lambda ()
   (list
    :height (or ivy-posframe-height ivy-height)
    :width ivy-posframe-width
    :min-height (or ivy-posframe-min-height ivy-height)
    :min-width (or ivy-posframe-min-width
                   (let* ((buf-rows (split-string
                                     (with-current-buffer ivy-posframe-buffer
                                       (buffer-string))
                                     "\n"))
                          (prompt (split-string
                                   (with-temp-buffer
                                     (ivy--insert-prompt)
                                     (buffer-string))
                                   "\n"))
                          (max-prompt-col (seq-max (seq-map #'length prompt))))
                     (max (seq-max (seq-map #'length buf-rows))
                          (+ max-prompt-col (length ivy-text) 2)))))))