Add "Discard", "Stage", and "Unstage" to right-click menu in Magit buffers

magit-context-menu.el

(require 'magit)

(defun magit-current-section-menu-label ()
  "Menu item label for section at point."
  (pcase (magit-diff-scope)
    ('hunk     "Hunk")
    ('hunks    "Hunks")
    ('file     "File")
    ('files    "Files")
    ('module   "Module")
    ('region   "Region")))

(defun magit-context-menu (menu click)
  "Populate MENU with commands that perform actions on magit sections at point."
  (save-excursion
    (mouse-set-point click)
    ;; Ignore log and commit buffers, only apply to status.
    (when (magit-section-match 'status magit-root-section)
      (when-let ((section-label (magit-current-section-menu-label)))
        (define-key-after menu [magit-separator] menu-bar-separator)

        (when (eq 'staged (magit-diff-type))
          (define-key-after menu [magit-unstage-thing-at-mouse]
            `(menu-item (concat "Unstage " ,section-label)
                        magit-unstage
                        :help "Unstage thing at point")))
        (when (member (magit-diff-type) '(unstaged untracked))
          (define-key-after menu [magit-stage-thing-at-mouse]
            `(menu-item (concat "Stage " ,section-label)
                        magit-stage
                        :help "Stage thing at point")))

        ;; `magit-section-match' without 2nd parameter uses section at point automatically.
        (when (magit-section-match '(magit-module-section
                                     magit-file-section
                                     magit-hunk-section))
          (define-key-after menu [magit-discard-thing-at-mouse]
            `(menu-item (concat "Discard " ,section-label)
                        magit-discard
                        :help "Discard thing at point"))))))
  menu)

(setq-default context-menu-functions
      '(context-menu-ffap
        magit-context-menu
        context-menu-highlight-symbol
        occur-context-menu
        context-menu-region
        context-menu-undo
        context-menu-dictionary))