这是一个令人沮丧的绝妙练习。出于某种原因，我的 python-mode / elpy 缓冲区总是有intent-tabs-mode nil. 我正在使用 python-mode 6.2.3、elpy 1.32.0 和 emacs 25.2.2。我的 .emacs 文件包含：
;; =============================================================================
;; Trying to get indentation to be tabs of width 4 spaces in Python is a real
;; pain. For some unknown reason, unlike EVERY other progmode file in the distro
;; python.el contains this gem:
;;
;; 5480: (set (make-local-variable 'tab-width) 8)
;;
;; which clobbers any defaults you might have, no questoins asked. It also has
;; this wonderful nugget:
;;
;; 5481: (set (make-local-variable 'indent-tabs-mode) nil)
;;
;; Because someone wants to force using spaces (so wby bother forcing
;; tab-width?)
;; -----------------------------------------------------------------------------
;; Do this first. Because of the above, if you don't python.el will clobber
;; your attempts to customize this stuff.
(load "python-mode")
;; Now follow the instructions sprinked all over the Interwebs by the thousands
;; of people frustrated by the above clobbering.
(add-hook 'python-mode-hook
;; Don't forget lambda(), God forbid
(lambda ()
;; Now set the tab-width you really want here and cross your fingers
(setq tab-width 4)
;; And tell python-mode to use tabs. I know lots of folks hate on
;; tabs, but whatever.
(setq indent-tabs-mode t)
;; If you want to make sure you don't have trailing whitespaces
;; at the end of line, uncomment this.
;;(add-to-list 'write-file-functions 'delete-trailing-whitespace)
)
)
但indent-tabs-mode仍然存在nil。当然，仅在 python 模式下。从describe-variablepython-mode / elpy 缓冲区中：
indent-tabs-mode is a variable defined in ‘C source code’.
Its value is nil
Original value was t
Local in buffer config; global value is t
Automatically becomes buffer-local when set.
This variable is safe as a file local variable if its value
satisfies the predicate ‘booleanp’.
Documentation:
Indentation can insert tabs if this is non-nil.
You can customize this variable.
我使用的 python-mode.el 版本包含以下 [第 955-964 行]：
"Python-mode starts `indent-tabs-mode' with the value specified here, default is nil. "
:type 'boolean
:tag "py-indent-tabs-mode"
:group 'python-mode)
[第 5159-5165 行]
["indent-tabs-mode"
(setq indent-tabs-mode
(not indent-tabs-mode))
:help "Indentation can insert tabs if this is non-nil.
Use `M-x customize-variable' to set it permanently"
:style toggle :selected indent-tabs-mode]
[第 6787-6820 行]
(defun py-toggle-indent-tabs-mode ()
"Toggle `indent-tabs-mode'.
Returns value of `indent-tabs-mode' switched to. "
(interactive)
(when
(setq indent-tabs-mode (not indent-tabs-mode))
(setq tab-width py-indent-offset))
(when (and py-verbose-p (called-interactively-p 'any)) (message "indent-tabs-mode %s py-indent-offset %s" indent-tabs-mode py-indent-offset))
indent-tabs-mode)
(defun py-indent-tabs-mode (arg &optional iact)
"With positive ARG switch `indent-tabs-mode' on.
With negative ARG switch `indent-tabs-mode' off.
Returns value of `indent-tabs-mode' switched to. "
(interactive "p")
(if (< 0 arg)
(progn
(setq indent-tabs-mode t)
(setq tab-width py-indent-offset))
(setq indent-tabs-mode nil))
(when (and py-verbose-p (or iact (called-interactively-p 'any))) (message "indent-tabs-mode %s py-indent-offset %s" indent-tabs-mode py-indent-offset))
indent-tabs-mode)
(defun py-indent-tabs-mode-on (arg)
"Switch `indent-tabs-mode' on. "
(interactive "p")
(py-indent-tabs-mode (abs arg)(called-interactively-p 'any)))
(defun py-indent-tabs-mode-off (arg)
"Switch `indent-tabs-mode' off. "
(interactive "p")
(py-indent-tabs-mode (- (abs arg))(called-interactively-p 'any)))
[第 22259-22266 行]
;; unconditional Hooks
;; (orgstruct-mode 1)
(add-hook 'python-mode-hook
(lambda ()
(setq imenu-create-index-function py--imenu-create-index-function)
(setq indent-tabs-mode py-indent-tabs-mode)))
(remove-hook 'python-mode-hook 'python-setup-brm)
再次（与上面几乎相同）[第 25021-25033 行]：
["indent-tabs-mode"
(setq indent-tabs-mode
(not indent-tabs-mode))
:help "Indentation can insert tabs if this is non-nil.
Use `M-x customize-variable' to set it permanently"
:style toggle :selected indent-tabs-mode]
["Tab indent"
(setq py-tab-indent
(not py-tab-indent))
:help "Non-nil means TAB in Python mode calls `py-indent-line'.Use `M-x customize-variable' to set it permanently"
:style toggle :selected py-tab-indent]
indent-tabs-mode我已经设置了可以在 to 的任何 *.el 文件中找到的任何定义的每个版本，但t没有任何效果。