emacs-29 f58452e3ae: Fix 'python-shell-buffer-substring' when START is in middle of 1st line

[Eli Zaretskii]

branch: emacs-29
commit f58452e3ae7ed595566028010128c99e3afb572b
Author: kobarity <kobarity@gmail.com>
Commit: Eli Zaretskii <eliz@gnu.org>

    Fix 'python-shell-buffer-substring' when START is in middle of 1st line
    
    * lisp/progmodes/python.el (python-shell-buffer-substring): Instead
    of checking whether START is point-min, check whether START is in
    the first line.  (Bug#60466)
    * test/lisp/progmodes/python-tests.el
    (python-shell-buffer-substring-18): New test.
---
 lisp/progmodes/python.el            |  9 +++++----
 test/lisp/progmodes/python-tests.el | 10 ++++++++++
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 59164d7d50..c399bbc64f 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -3766,15 +3766,16 @@ the python shell:
                         (line-beginning-position)
                       start))))
          (substring (buffer-substring-no-properties start end))
-         (starts-at-point-min-p (save-restriction
-                                  (widen)
-                                  (= (point-min) start)))
+         (starts-at-first-line-p (save-restriction
+                                   (widen)
+                                   (goto-char start)
+                                   (= (line-number-at-pos) 1)))
          (encoding (python-info-encoding))
          (toplevel-p (zerop (save-excursion
                               (goto-char start)
                               (python-util-forward-comment 1)
                               (current-indentation))))
-         (fillstr (cond (starts-at-point-min-p
+         (fillstr (cond (starts-at-first-line-p
                          nil)
                         ((not no-cookie)
                          (concat
diff --git a/test/lisp/progmodes/python-tests.el 
b/test/lisp/progmodes/python-tests.el
index eac558db10..df71990278 100644
--- a/test/lisp/progmodes/python-tests.el
+++ b/test/lisp/progmodes/python-tests.el
@@ -4520,6 +4520,16 @@ def foo():
                      (python-tests-look-at "\"\"\""))
                     "# -*- coding: utf-8 -*-\n\nif True:\n    a = 1\n    b = 
2\n\n"))))
 
+(ert-deftest python-shell-buffer-substring-18 ()
+  "Check substring from the part of the first line."
+  (python-tests-with-temp-buffer
+   "s = 'test'
+"
+   (should (string= (python-shell-buffer-substring
+                     (python-tests-look-at "'test'")
+                     (pos-eol))
+                    "'test'"))))
+
 
 
 ;;; Shell completion