Stop the AI from sorting hands in place; unskip full-game tests

Under Emacs 28 and earlier, sort relinks a list destructively, so the
variable that held the old head can end up holding only a tail.  Four
computer-player choices sorted a list that shared structure with the
player's stored hand (cl-remove-if-not returns its argument when it
removes nothing), so Bridge, Briscola, Pitch and Euchre dropped cards
from hands mid-deal and then stopped on (= nil N).  Emacs 29's sort
reorders in place, which hid the bug there.

The previous commit skipped cgt-bridge-full and cgt-trick-ext-full
unless SVG is available, but both render text in batch; they failed
on Emacs 27 for this reason, not for want of SVG.

* card-games-bridge.el (card-games-bridge--ai-play):
* card-games-trick-ext.el (card-games-tx--ai)
(card-games-trick--ai-play) <pitch>: Sort a copy, never the hand.
* test/card-games-tests.el (cgt-bridge-full, cgt-trick-ext-full):
Drop the SVG skip.
(cgt--hands-snapshot, cgt-ai-play-leaves-hands-alone): New test; it
fails without the fix on Emacs 27 and on Emacs 29.
* NEWS: Note the fix.

Assisted-by: Mentat (for Corwin; claude-opus-5-5)
This commit is contained in:
Corwin Brust 2026-10-05 15:58:25 -05:00
parent e78fe38381
commit 74af63a089
4 changed files with 57 additions and 7 deletions

View file

@ -98,9 +98,9 @@ POWERFN, LEDFN rank cards; VALUEFN gives a card's point worth."
trump powerfn ledfn))
(push c winners) (push c losers)))
(if winners
(car (sort winners (lambda (a b) (< (funcall powerfn a trump led)
(car (sort (copy-sequence winners) (lambda (a b) (< (funcall powerfn a trump led)
(funcall powerfn b trump led)))))
(car (sort (or losers legal)
(car (sort (copy-sequence (or losers legal))
(lambda (a b) (< (funcall valuefn a) (funcall valuefn b))))))))))
(defun card-games-tx--plain-led (card _trump) "Return CARD's suit (the plain led suit)." (car card))
@ -236,8 +236,8 @@ SEAT plays CARD as usual once trump is fixed."
(dotimes (s 4)
(let ((v (card-games-pitch--suit-strength game seat s)))
(when (> v bestv) (setq bestv v best s))))
(car (sort (cl-remove-if-not (lambda (c) (= (car c) best))
(card-games-trick--hand game seat))
(car (sort (copy-sequence (cl-remove-if-not (lambda (c) (= (car c) best))
(card-games-trick--hand game seat)))
(lambda (a b) (> (cdr a) (cdr b))))))
(card-games-tx--ai game seat #'card-games-pitch--power #'card-games-tx--plain-led
(lambda (c) (card-games-pitch--pip (cdr c))))))