bug#68559: [PATCH] Improve Python shell completion

[Liu Hui <liuhui1610@gmail.com>]

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On Tue, Mar 12, 2024 at 12:02 AM Basil L. Contovounesios
<basil@contovou.net> wrote:
>
> Liu Hui [2024-03-11 19:35 +0800] wrote:
>
> > On Fri, Mar 8, 2024 at 11:44 PM Basil L. Contovounesios
> > <basil@contovou.net> wrote:
> >>
> >> Liu Hui [2024-03-06 18:14 +0800] wrote:
> >>
> >> > -                   (string-match-p "ipython[23]?\\'" python-shell-interpreter)))))
> >> > +                   (or (string-match-p "ipython[23]?\\'" python-shell-interpreter)
> >> > +                       (string= python-shell-readline-completer-delims ""))))))
> >>
> >> Just curious: what does the empty string signify?
> >>
> >> [ If it's not just a dumb question, perhaps the meaning could be added
> >>   to the variable's docstring/commentary. ]
> >
> > The empty string means no characters are considered delimiters and the
> > readline completion could consider the entire line of input without
> > breaking it into parts based on typical delimiters like spaces or
> > punctuation. The docstring is updated in the attached patch.
>
> Thanks!  But that makes me wonder: in the cases where we check
>
>   (string= python-shell-readline-completer-delims "")
>
> is there a possibility that the variable's value will be nil?
> (In which case we should compare with equal instead of string=.)

Yes, it is a string with native completion and may be nil with
non-native completion. I have updated the patch. Thanks.

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From d204d5ae2439dc76662e4e13491ff103216a2d12 Mon Sep 17 00:00:00 2001
From: Liu Hui <liuhui1610@gmail.com>
Date: Mon, 26 Feb 2024 18:46:36 +0800
Subject: [PATCH] Detect the readline support for Python shell completion

* lisp/progmodes/python.el
(python-shell-comint-watch-for-first-prompt-output-filter):
Detect the readline support.
(python-shell-readline-completer-delims): Update docstring.
(python-shell-completion-native-setup): Move the readline
detection code to ...
(python-shell-readline-detect): ... new function.
(python-shell-completion-native-turn-on-maybe): Skip if Python
has no readline support.
(python-shell-completion-at-point): Respect the delimiter of
readline completer in non-native completion.
* test/lisp/progmodes/python-tests.el
(python-shell-completion-at-point-1)
(python-shell-completion-at-point-native-1)
(python-completion-at-point-1, python-completion-at-point-2)
(python-completion-at-point-pdb-1)
(python-completion-at-point-while-running-1)
(python-completion-at-point-native-1)
(python-completion-at-point-native-2)
(python-completion-at-point-native-with-ffap-1)
(python-completion-at-point-native-with-eldoc-1): Skip tests if
Python has no readline support.
(python-shell-completion-at-point-jedi-completer): Add test for
non-native Python shell completion. (bug#68559)
---
 lisp/progmodes/python.el            | 29 ++++++++++++++++++++-------
 test/lisp/progmodes/python-tests.el | 31 ++++++++++++++++++++++++-----
 2 files changed, 48 insertions(+), 12 deletions(-)

diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 587d0b36304..c94bb4fc550 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -3601,6 +3601,7 @@ python-shell-comint-watch-for-first-prompt-output-filter
           (python-shell-send-string-no-output python-shell-eval-file-setup-code))
         (with-current-buffer (current-buffer)
           (let ((inhibit-quit nil))
+            (python-shell-readline-detect)
             (run-hooks 'python-shell-first-prompt-hook))))))
   output)
 
@@ -4439,7 +4440,23 @@ python-shell-completion-native-try-output-timeout
 
 (defvar python-shell-readline-completer-delims nil
   "Word delimiters used by the readline completer.
-It is automatically set by Python shell.")
+It is automatically set by Python shell.  An empty string means no
+characters are considered delimiters and the readline completion
+considers the entire line of input.  A value of nil means the Python
+shell has no readline support.")
+
+(defun python-shell-readline-detect ()
+  "Detect the readline support for Python shell completion."
+  (let* ((process (python-shell-get-process))
+         (output (python-shell-send-string-no-output "
+try:
+    import readline
+    print(readline.get_completer_delims())
+except:
+    print('No readline support')" process)))
+    (setq-local python-shell-readline-completer-delims
+                (unless (string-search "No readline support" output)
+                  (string-trim-right output)))))
 
 (defvar python-shell-completion-native-redirect-buffer
   " *Python completions redirect*"
@@ -4579,10 +4596,6 @@ python-shell-completion-native-setup
 __PYTHON_EL_native_completion_setup()" process)))
     (when (string-match-p "python\\.el: native completion setup loaded"
                           output)
-      (setq-local python-shell-readline-completer-delims
-                  (string-trim-right
-                   (python-shell-send-string-no-output
-                    "import readline; print(readline.get_completer_delims())")))
       (python-shell-completion-native-try))))
 
 (defun python-shell-completion-native-turn-off (&optional msg)
@@ -4611,7 +4624,8 @@ python-shell-completion-native-turn-on-maybe
       (cond
        ((python-shell-completion-native-interpreter-disabled-p)
         (python-shell-completion-native-turn-off msg))
-       ((python-shell-completion-native-setup)
+       ((and python-shell-readline-completer-delims
+             (python-shell-completion-native-setup))
         (when msg
           (message "Shell native completion is enabled.")))
        (t
@@ -4783,7 +4797,8 @@ python-shell-completion-at-point
                (with-current-buffer (process-buffer process)
                  (if python-shell-completion-native-enable
                      (string= python-shell-readline-completer-delims "")
-                   (string-match-p "ipython[23]?\\'" python-shell-interpreter)))))
+                   (or (string-match-p "ipython[23]?\\'" python-shell-interpreter)
+                       (equal python-shell-readline-completer-delims ""))))))
          (start
           (if (< (point) line-start)
               (point)
diff --git a/test/lisp/progmodes/python-tests.el b/test/lisp/progmodes/python-tests.el
index 1ceee690cfb..e11440cdb5b 100644
--- a/test/lisp/progmodes/python-tests.el
+++ b/test/lisp/progmodes/python-tests.el
@@ -4783,6 +4783,7 @@ python-shell-completion-at-point-1
   (python-tests-with-temp-buffer-with-shell
    ""
    (python-shell-with-shell-buffer
+     (skip-unless python-shell-readline-completer-delims)
      (insert "import abc")
      (comint-send-input)
      (python-tests-shell-wait-for-prompt)
@@ -4797,6 +4798,7 @@ python-shell-completion-at-point-native-1
    ""
    (python-shell-completion-native-turn-on)
    (python-shell-with-shell-buffer
+     (skip-unless python-shell-readline-completer-delims)
      (insert "import abc")
      (comint-send-input)
      (python-tests-shell-wait-for-prompt)
@@ -4883,11 +4885,14 @@ python-shell-completion-at-point-jedi-completer
     (python-tests-with-temp-buffer-with-shell
      ""
      (python-shell-with-shell-buffer
-      (python-shell-completion-native-turn-on)
-      (skip-unless (string= python-shell-readline-completer-delims ""))
-      (python-tests--completion-module)
-      (python-tests--completion-parameters)
-      (python-tests--completion-extra-context)))))
+       (skip-unless (string= python-shell-readline-completer-delims ""))
+       (python-shell-completion-native-turn-off)
+       (python-tests--completion-module)
+       (python-tests--completion-parameters)
+       (python-shell-completion-native-turn-on)
+       (python-tests--completion-module)
+       (python-tests--completion-parameters)
+       (python-tests--completion-extra-context)))))
 
 (ert-deftest python-shell-completion-at-point-ipython ()
   "Check if Python shell completion works for IPython."
@@ -4924,6 +4929,8 @@ python-completion-at-point-1
 import abc
 "
    (let ((inhibit-message t))
+     (python-shell-with-shell-buffer
+       (skip-unless python-shell-readline-completer-delims))
      (python-shell-send-buffer)
      (python-tests-shell-wait-for-prompt)
      (goto-char (point-max))
@@ -4940,6 +4947,8 @@ python-completion-at-point-2
 import abc
 "
    (let ((inhibit-message t))
+     (python-shell-with-shell-buffer
+       (skip-unless python-shell-readline-completer-delims))
      (python-shell-send-buffer)
      (python-tests-shell-wait-for-prompt)
      (python-shell-with-shell-buffer
@@ -4959,6 +4968,8 @@ python-completion-at-point-pdb-1
 print('Hello')
 "
    (let ((inhibit-message t))
+     (python-shell-with-shell-buffer
+       (skip-unless python-shell-readline-completer-delims))
      (python-shell-send-buffer)
      (python-tests-shell-wait-for-prompt)
      (goto-char (point-max))
@@ -4975,6 +4986,8 @@ python-completion-at-point-while-running-1
 time.sleep(3)
 "
    (let ((inhibit-message t))
+     (python-shell-with-shell-buffer
+       (skip-unless python-shell-readline-completer-delims))
      (python-shell-send-buffer)
      (goto-char (point-max))
      (insert "time.")
@@ -4987,6 +5000,8 @@ python-completion-at-point-native-1
 import abc
 "
    (let ((inhibit-message t))
+     (python-shell-with-shell-buffer
+       (skip-unless python-shell-readline-completer-delims))
      (python-shell-completion-native-turn-on)
      (python-shell-send-buffer)
      (python-tests-shell-wait-for-prompt)
@@ -5004,6 +5019,8 @@ python-completion-at-point-native-2
 import abc
 "
    (let ((inhibit-message t))
+     (python-shell-with-shell-buffer
+       (skip-unless python-shell-readline-completer-delims))
      (python-shell-completion-native-turn-on)
      (python-shell-send-buffer)
      (python-tests-shell-wait-for-prompt)
@@ -5020,6 +5037,8 @@ python-completion-at-point-native-with-ffap-1
 import abc
 "
    (let ((inhibit-message t))
+     (python-shell-with-shell-buffer
+       (skip-unless python-shell-readline-completer-delims))
      (python-shell-completion-native-turn-on)
      (python-shell-send-buffer)
      (python-tests-shell-wait-for-prompt)
@@ -5036,6 +5055,8 @@ python-completion-at-point-native-with-eldoc-1
 import abc
 "
    (let ((inhibit-message t))
+     (python-shell-with-shell-buffer
+       (skip-unless python-shell-readline-completer-delims))
      (python-shell-completion-native-turn-on)
      (python-shell-send-buffer)
      (python-tests-shell-wait-for-prompt)
-- 
2.25.1