Hi, There are some problems in filling Python's strings, which are caused by the same portion of the code. Here are the steps to reproduce the first problem: 1. emacs -Q 2. C-x C-f somefile1.py 3. Enter the following program: #+begin_src python s1 = 'abc' s2 = 'def' #+end_src 4. Place point within the first string (abc). 6. M-q The lines will be merged into a single line. #+begin_src python s1 = 'abc' s2 = 'def' #+end_src This problem occurs in Emacs 27 and later. Second problem can be reproduced with the following steps: 1. emacs -Q 2. C-x C-f somefile2.py 3. Enter the following program: #+begin_src python s = '''abcdefghijklmnopqrstuvwxyz abcdefghijklmnopqrstuvwxyz abcdefghijklmnopqrstuvwxyz''' #+end_src 4. Place point at the first or third quote of the starting triple quotes. 5. M-q The line is not filled. However, if the point is placed at the second quote or within the string, the line will be filled as follows: #+begin_src python s = '''abcdefghijklmnopqrstuvwxyz abcdefghijklmnopqrstuvwxyz abcdefghijklmnopqrstuvwxyz''' #+end_src When the point is placed at the ending triple quotes, the line will be filled if the point is at the first or third quote. This problem occurs in Emacs 28 and later. Third problem can be reproduced with the following steps: 1. emacs -Q 2. C-x C-f somefile3.py 3. Enter the following program: #+begin_src python s = 'abcdefghijklmnopqrstuvwxyz abcdefghijklmnopqrstuvwxyz abcdefghijklmnopqrstuvwxyz' #+end_src 4. Place point within the string. 5. M-q The line will be split into 2 lines. #+begin_src python s = 'abcdefghijklmnopqrstuvwxyz abcdefghijklmnopqrstuvwxyz abcdefghijklmnopqrstuvwxyz' #+end_src This is not a correct Python program anymore because a single quoted string can not span multiple lines unless the end of line is escaped using a backslash. The docstring of `python-fill-paragraph' says: `fill-paragraph-function' handling multi-line strings and possibly comments. Although it is possible to make a multi-line single quoted string by escaping the end of line using backslash, triple quoted strings are usually used for multi-line strings. So I think `python-fill-paragraph' should not do anything with single quoted strings. The cause of the first problem is similar to Bug#58780. In `python-fill-string', the string is searched for with the following code: (or (python-syntax-context 'string) (and (equal (string-to-syntax "|") (syntax-after (point))) (point))))) and the end of the string is searched for with the following code: (or (re-search-forward (rx (syntax string-delimiter)) nil t) (goto-char (point-max))) These codes used to be appropriate, but it is not correct after the following commit which is included in Emacs 27 and later: commit 4b39b741f1949ebad1dfccc5032dfce521bedc2a Author: Stefan Monnier Date: Tue Apr 9 15:08:21 2019 -0400 python.el: don't syntax-propertize single/double quoted strings * lisp/progmodes/python.el (python-syntax-propertize-function): Only mark triple-quoted strings, let the normal syntax-table handle the rest. (python-syntax-stringify): Adjust accordingly. From this commit, single quoted strings can not be identified by string-delimiter and can only be identified by string-quote. In the fix of Bug#58780, I added `forward-sexp' to search for the end of single quoted string. However, considering the third problem, I would prefer to have `python-fill-paragraph' and `python-fill-string' search only for triple quoted strings in this case. The second problem occurs after the following commit included in Emacs 28 and later: commit 0646c6817139aa905a2f6079fdc82eb4be944de0 Author: João Távora Date: Sun Sep 19 11:42:20 2021 +0100 Make syntax-ppss more accurate for Python triple quotes (bug#49518) By putting delimiter syntax on the last character of Python triple-quoted strings, this makes syntax-ppss be more accurate. This commit narrows the range of string-delimiter from outermost quotes to innermost quotes, and results in `python-fill-paragraph' not recognizing the string when point is at some quotes. Attached is a patch to fix these problems. Main changes are: 1. single-quoted-string and triple-quoted-string are added as a TYPE argument of `python-syntax-context'. 2. New helper function `python-info-triple-quoted-string-p' is added to detect triple quoted strings including quotes. 3. `python-fill-paragraph' and `python-fill-string' use `python-info-triple-quoted-string-p' to detect triple quoted strings only. I look forward to your comments. -- In GNU Emacs 30.0.50 (build 3, x86_64-pc-linux-gnu, X toolkit, cairo version 1.16.0, Xaw scroll bars) of 2023-03-10 built on ubuntu Repository revision: 8ee205d232574e12921b052c7e93b7e16d6f1187 Repository branch: master System Description: Ubuntu 22.04.2 LTS Configured features: ACL CAIRO FREETYPE GIF GLIB GMP GNUTLS GSETTINGS HARFBUZZ JPEG LIBSELINUX LIBXML2 MODULES NOTIFY INOTIFY PDUMPER PNG SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS TREE_SITTER X11 XDBE XIM XPM LUCID ZLIB Important settings: value of $LANG: en_US.UTF-8 locale-coding-system: utf-8-unix Major mode: Python Minor modes in effect: tooltip-mode: t global-eldoc-mode: t eldoc-mode: t show-paren-mode: t electric-indent-mode: t mouse-wheel-mode: t tool-bar-mode: t menu-bar-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t blink-cursor-mode: t line-number-mode: t transient-mark-mode: t auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t Load-path shadows: None found. 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