(defun sacha/planner-create-task-from-buffer ()
  (interactive)
  (let ((annotation (run-hook-with-args-until-success 'planner-annotation-functions))
        (default-text "")
        task-text
        plan
        date
        (case-fold-search t))
    (setq planner-default-page
          (if (and (planner-derived-mode-p 'planner-mode)
                   (planner-page-name)
                   (not (string-match planner-date-regexp
                                      (planner-page-name))))
              (planner-page-name)
            planner-default-page))
    ;; INTERESTING CODE STARTS HERE
    (save-excursion
      (goto-char (point-min))
      (when (and (re-search-forward "^+++" nil t)
                 (re-search-forward "^@@" nil t))
        (setq default-text "Merge patch for ")))
    (setq task-text (read-string "Describe task: "
                                 default-text))
    (when (or (string-match "planner" annotation)
              (string-match "planner" task-text))
      (setq planner-default-page "PlannerModeMaintenance"))
    ;; END INTERESTING CODE
    (setq date (cond
                ;; Universal prefix means pick up from current page
                ((and current-prefix-arg
                      (derived-mode-p 'planner-mode)
                      (string-match planner-date-regexp (planner-page-name)))
                 (planner-page-name))
                ;; Date selected in calendar
                ((condition-case nil (calendar-cursor-to-date) (error nil))
                 (planner-date-to-filename (calendar-cursor-to-date)))
                ;; Prompt for date
                (t (let ((planner-expand-name-favor-future-p
                          (or planner-expand-name-favor-future-p
                              planner-task-dates-favor-future-p)))
                     (planner-read-date)))))
    (setq plan
          (if (and current-prefix-arg (planner-derived-mode-p 'planner-mode)
                   (not (string-match planner-date-regexp (planner-page-name))))
              ;; Universal prefix means pick up from current page
              (planner-page-name)
            (planner-read-non-date-page
             (planner-file-alist))))
    (planner-create-task-from-buffer task-text date plan)))

../emacs/planner-config.el