I maintain sage-mode which is implemented as a derived mode of
python-mode. Likewise with inferior-sage-mode and inferior-python-mode.
There are some places in python-mode where major-mode is checked with
eq. This causes some weird breakage when using sage-mode, particularly
it causes inferior-sage-mode to hang in some situations [1]. I could
probably work around it on the sage-mode side, but I think it makes
sense to use derived-mode-p instead, so I'm including this patch
-Ivan
diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index b230992..06f1ffe 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -2221,7 +2221,7 @@ Signals an error if no shell buffer is available for current buffer."
(when (and python-shell--font-lock-buffer
(buffer-live-p python-shell--font-lock-buffer))
(kill-buffer python-shell--font-lock-buffer)
- (when (eq major-mode 'inferior-python-mode)
+ (when (derived-mode-p 'inferior-python-mode)
(setq python-shell--font-lock-buffer nil)))))
(defmacro python-shell-font-lock-with-font-lock-buffer (&rest body)
@@ -2238,7 +2238,7 @@ also `with-current-buffer'."
(set-buffer python-shell--font-lock-buffer)
(set (make-local-variable 'delay-mode-hooks) t)
(let ((python-indent-guess-indent-offset nil))
- (when (not (eq major-mode 'python-mode))
+ (when (not (derived-mode-p 'python-mode))
(python-mode))
,@body))))
@@ -2501,7 +2501,7 @@ startup."
(defun python-shell-get-buffer ()
"Return inferior Python buffer for current buffer.
If current buffer is in `inferior-python-mode', return it."
- (if (eq major-mode 'inferior-python-mode)
+ (if (derived-mode-p 'inferior-python-mode)
(current-buffer)
(let* ((dedicated-proc-name (python-shell-get-process-name t))
(dedicated-proc-buffer-name (format "*%s*" dedicated-proc-name))
@@ -3482,7 +3482,7 @@ The skeleton will be bound to python-skeleton-NAME."
(defun python-ffap-module-path (module)
"Function for `ffap-alist' to return path for MODULE."
(let ((process (or
- (and (eq major-mode 'inferior-python-mode)
+ (and (derived-mode-p 'inferior-python-mode)
(get-buffer-process (current-buffer)))
(python-shell-get-process))))
(if (not process)