dir-locals.el 设置未应用于某些变量

Question

我想使用我的 .dir-locals.el 在项目上设置 virtualenv 名称。该变量已设置，但在用作其他连接变量中的参数时不被视为。

我尝试将 .dir-locals.el 文件添加到 python 项目。在其中，我为这个特定项目设置了 virtualenv 根名称。之后我启动 Emacs，打开一个 .py 文件检查是否所有需要的变量都用 virtualenv 名称进行了更改。

我的 emacs 配置中关于 python-mode 的部分

;;; Python mode

(require 'python)
(ensure-package 'python-environment)
(require 'python-environment)
(ensure-package 'python-mode)
(require 'python-mode)
;;; dash used for pip-requirements
(ensure-package 'dash)
(require 'dash)
(require 'pip-requirements)
(require 'jedi-core)
(require 'company-jedi)


(defun init-python-mode()
  (setq-local tab-width 4)
  (setq-local indent-tabs-mode nil)
  (set (make-local-variable 'company-backends)
       '((company-jedi company-dabbrev-code)
         company-capf company-files))
  (setq python-environment-directory (expand-file-name "~/.virtualenvs")
      python-indent-guess-indent-offset nil
      python-indent-offset 4
      jedi:complete-on-dot t
      jedi:use-shortcuts t
      jedi:tooltip-method nil
      jedi:get-in-function-call-delay 0
      python-shell-interpreter (concat python-environment-directory
                                       "/" python-environment-default-root-name
                                       "/bin" "/python")
      jedi:server-command (list (concat python-environment-directory
                                        "/" python-environment-default-root-name
                                        "/bin" "/jediepcserver"))
      python-shell-interpreter (concat python-environment-directory
                                       "/" python-environment-default-root-name
                                       "/bin" "/python")
      flycheck-python-pylint-executable (concat python-environment-directory
                                                "/" python-environment-default-root-name
                                                "/bin" "/pylint")
      flycheck-python-flake8-executable (concat python-environment-directory
                                                "/" python-environment-default-root-name
                                                "/bin" "/flake8")
      flycheck-python-pycompile-executable (concat python-environment-directory
                                                   "/" python-environment-default-root-name
                                                   "/bin" "/python")
      )
  (flycheck-mode t)
)

(defun after-init-python-mode()
  (eldoc-mode -1)
  )

(define-key python-mode-map (kbd "C-c C-k") #'comment-dwim)

(add-to-list 'auto-mode-alist '("\\.py\\'" . python-mode))

(add-hook 'python-mode-hook #'init-python-mode)
(add-hook 'python-mode-hook #'jedi:setup)
(add-hook 'python-mode-hook #'after-init-python-mode)

项目的 .dir-locals.el 文件

;;; Directory Local Variables
;;; For more information see (info "(emacs) Directory Variables")

((python-mode . ((python-environment-default-root-name . "abc")
         )))

Emacs 似乎对 .dir-locals.el 变量做出反应，我确认这些变量在启动时是安全的。之后，通过执行：'describe-variable python-environment-default-root-name' 我得到这个：

python-environment-default-root-name is a variable defined in ‘python-environment.el’.
Its value is "abc"
Original value was "default"
Local in buffer setup.py; global value is "default"

  This variable’s value is directory-local, set by the file
  ‘/home/mkj/dev/adm/.dir-locals.el’.

...这是预期的。

当执行：'describe-variable jedi:server-command'、'describe-variable python-shell-interpreter'，以及使用 python-environment-default-root-name 的其他变量时，我得到这个：

jedi:server-command is a variable defined in ‘jedi-core.el’.
Its value is ("/home/mkj/.virtualenvs/default/bin/jediepcserver")

  This variable may be risky if used as a file-local variable.

python-shell-interpreter is a variable defined in ‘python.el’.
Its value is "/home/mkj/.virtualenvs/default/bin/python"
Original value was "python"

在我看来，使用 python-environment-default-root-name 的变量名的 setq 仅在设置默认值并且 .dir-locals.el 值被忽略或设置太晚时设置一次。

这里是否存在竞争条件，或者这只是为 python 模式设置基于 virtualenv 的变量的错误方法？

Answer 1

您可以在您的钩子中添加对hack-local-variables 的调用，以使 dir-locals 可用。通常，只有mode 局部变量会在你的钩子之前设置，通过调用(hack-local-variables t)。与python-mode、你的钩子和hack-local-variables 相关的调用通常看起来像，

1 -> (normal-mode t)
| 2 -> (hack-local-variables t)
| 2 <- hack-local-variables: nil
| 2 -> (python-mode)
| | 3 -> (my-python-hook)
| | 3 <- my-python-hook: ("~/.virtualenvs/default/bin/jediepcserver")
| | 3 -> (hack-local-variables no-mode) ;; you want this called prior to your hook
| | 3 <- hack-local-variables: nil
| 2 <- python-mode: nil
1 <- normal-mode: t

所以，你可以修改你的钩子，

(defun my-python-hook ()
  (hack-local-variables)
  ;; ...
  )

不过，这似乎不是一个好的解决方案。我不使用 virtualenv，但似乎 python-environment-virtualenv 在这里是相关的。

Answer 2

我发现 elpy 更适合此目的。它似乎可以无缝地更改公司后端、python 解释器、flycheck 等的变量，而无需更改 pyvenv-workon 变量。