1 files changed, 28 insertions, 3 deletions

diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 9c5e1e5ee6c..848a26229e6 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -3816,6 +3816,16 @@ variable.
   (compilation-shell-minor-mode 1)
   (python-pdbtrack-setup-tracking))
 
+(defvar-local python-shell--process-cache)
+(defvar-local python-shell--process-cache-valid)
+
+(defun python-shell--invalidate-process-cache ()
+  "Invalidate process cache."
+  (dolist (buffer (buffer-list))
+    (with-current-buffer buffer
+      (setq python-shell--process-cache nil
+            python-shell--process-cache-valid nil))))
+
 (defun python-shell-make-comint (cmd proc-name &optional show internal)
   "Create a Python shell comint buffer.
 CMD is the Python command to be executed and PROC-NAME is the
@@ -3832,6 +3842,7 @@ killed."
       (let* ((proc-buffer-name
               (format (if (not internal) "*%s*" " *%s*") proc-name)))
         (when (not (comint-check-proc proc-buffer-name))
+          (python-shell--invalidate-process-cache)
           (let* ((cmdlist (split-string-and-unquote cmd))
                  (interpreter (car cmdlist))
                  (args (cdr cmdlist))
@@ -3955,7 +3966,15 @@ If current buffer is in `inferior-python-mode', return it."
 
 (defun python-shell-get-process ()
   "Return inferior Python process for current buffer."
-  (get-buffer-process (python-shell-get-buffer)))
+  (unless (and python-shell--process-cache-valid
+               (or (not python-shell--process-cache)
+                   (and (process-live-p python-shell--process-cache)
+                        (buffer-live-p
+                         (process-buffer python-shell--process-cache)))))
+    (setq python-shell--process-cache
+          (get-buffer-process (python-shell-get-buffer))
+          python-shell--process-cache-valid t))
+  python-shell--process-cache)
 
 (defun python-shell-get-process-or-error (&optional interactivep)
   "Return inferior Python process for current buffer or signal error.
@@ -4514,6 +4533,13 @@ def __PYTHON_EL_get_completions(text):
   "Code used to setup completion in inferior Python processes."
   :type 'string)
 
+(defun python-shell-completion-send-setup-code ()
+  "Send `python-shell-completion-setup-code' to inferior Python process."
+  (python-shell-send-string-no-output python-shell-completion-setup-code))
+
+(add-hook 'python-shell-first-prompt-hook
+          #'python-shell-completion-send-setup-code)
+
 (define-obsolete-variable-alias
   'python-shell-completion-module-string-code
   'python-shell-completion-string-code
@@ -4844,8 +4870,7 @@ With argument MSG show activation/deactivation message."
   (with-current-buffer (process-buffer process)
     (let ((completions
            (python-shell-send-string-no-output
-            (format "%s\nprint(__PYTHON_EL_get_completions(%s))"
-                    python-shell-completion-setup-code
+            (format "print(__PYTHON_EL_get_completions(%s))"
                     (python-shell--encode-string input))
             process)))
       (condition-case nil