Make 'copy-tree' work with records

* doc/lispref/lists.texi (Building Cons Cells and Lists): Document
new behavior of 'copy-tree'.
* doc/lispref/records.texi (Record Functions): Cross-reference to
lists.texi.
* etc/NEWS: Mention change.  (Bug#63509)
* lisp/emacs-lisp/shortdoc.el: Add 'copy-tree' example to vector
group.
* lisp/subr.el (copy-tree): Recurse into records as well as
vectors when optional second argument is non-nil. Rename second
argument from VECP to VECTOR-LIKE-P.
* test/lisp/subr-tests.el: Test new behavior.

doc/lispref/lists.texi

@@ -696,16 +696,17 @@ not a list, the sequence's elements do not become elements of the
 resulting list.  Instead, the sequence becomes the final @sc{cdr}, like
 any other non-list final argument.
 
-@defun copy-tree tree &optional vecp
+@defun copy-tree tree &optional vector-like-p
 This function returns a copy of the tree @var{tree}.  If @var{tree} is a
 cons cell, this makes a new cons cell with the same @sc{car} and
 @sc{cdr}, then recursively copies the @sc{car} and @sc{cdr} in the
 same way.
 
 Normally, when @var{tree} is anything other than a cons cell,
-@code{copy-tree} simply returns @var{tree}.  However, if @var{vecp} is
-non-@code{nil}, it copies vectors too (and operates recursively on
-their elements).  This function cannot cope with circular lists.
+@code{copy-tree} simply returns @var{tree}.  However, if
+@var{vector-like-p} is non-@code{nil}, it copies vectors and records
+too (and operates recursively on their elements).  This function
+cannot cope with circular lists.
 @end defun
 
 @defun flatten-tree tree

doc/lispref/records.texi

@@ -81,6 +81,9 @@ This function returns a new record with type @var{type} and
 @end example
 @end defun
 
+@code{copy-tree} works with records when its optional second argument
+is non-@code{nil} (@pxref{Building Lists}).
+
 @node Backward Compatibility
 @section Backward Compatibility
 

etc/NEWS

@@ -585,6 +585,9 @@ Since circular alias chains now cannot occur, 'function-alias-p',
 'indirect-function' and 'indirect-variable' will never signal an error.
 Their 'noerror' arguments have no effect and are therefore obsolete.
 
++++
+** 'copy-tree' now copies records when its optional argument is non-nil.
+
 
 * Changes in Emacs 30.1 on Non-Free Operating Systems
 

lisp/emacs-lisp/shortdoc.el

@@ -833,6 +833,8 @@ A FUNC form can have any number of `:no-eval' (or `:no-value'),
   (seq-subseq
    :eval (seq-subseq [1 2 3 4 5] 1 3)
    :eval (seq-subseq [1 2 3 4 5] 1))
+  (copy-tree
+   :eval (copy-tree [1 2 3 4]))
   "Mapping Over Vectors"
   (mapcar
    :eval (mapcar #'identity [1 2 3]))

lisp/subr.el

@@ -824,26 +824,26 @@ of course, also replace TO with a slightly larger value
                 next (+ from (* n inc)))))
       (nreverse seq))))
 
-(defun copy-tree (tree &optional vecp)
+(defun copy-tree (tree &optional vector-like-p)
   "Make a copy of TREE.
 If TREE is a cons cell, this recursively copies both its car and its cdr.
 Contrast to `copy-sequence', which copies only along the cdrs.  With second
-argument VECP, this copies vectors as well as conses."
+argument VECTOR-LIKE-P, this copies vectors and records as well as conses."
   (declare (side-effect-free error-free))
   (if (consp tree)
       (let (result)
 	(while (consp tree)
 	  (let ((newcar (car tree)))
-	    (if (or (consp (car tree)) (and vecp (vectorp (car tree))))
-		(setq newcar (copy-tree (car tree) vecp)))
+	    (if (or (consp (car tree)) (and vector-like-p (or (vectorp (car tree)) (recordp (car tree)))))
+		(setq newcar (copy-tree (car tree) vector-like-p)))
 	    (push newcar result))
 	  (setq tree (cdr tree)))
 	(nconc (nreverse result)
-               (if (and vecp (vectorp tree)) (copy-tree tree vecp) tree)))
-    (if (and vecp (vectorp tree))
+               (if (and vector-like-p (or (vectorp tree) (recordp tree))) (copy-tree tree vector-like-p) tree)))
+    (if (and vector-like-p (or (vectorp tree) (recordp tree)))
 	(let ((i (length (setq tree (copy-sequence tree)))))
 	  (while (>= (setq i (1- i)) 0)
-	    (aset tree i (copy-tree (aref tree i) vecp)))
+	    (aset tree i (copy-tree (aref tree i) vector-like-p)))
 	  tree)
       tree)))
 

test/lisp/subr-tests.el

@@ -1206,5 +1206,36 @@ final or penultimate step during initialization."))
     (should (equal a-dedup '("a" "b" "a" "b" "c")))
     (should (eq a a-dedup))))
 
+(ert-deftest subr--copy-tree ()
+  (should (eq (copy-tree nil) nil))
+  (let* ((a (list (list "a") "b" (list "c") "g"))
+         (copy1 (copy-tree a))
+         (copy2 (copy-tree a t)))
+    (should (equal a copy1))
+    (should (equal a copy2))
+    (should-not (eq a copy1))
+    (should-not (eq a copy2)))
+  (let* ((a (list (list "a") "b" (list "c" (record 'foo "d")) (list ["e" "f"]) "g"))
+         (copy1 (copy-tree a))
+         (copy2 (copy-tree a t)))
+    (should (equal a copy1))
+    (should (equal a copy2))
+    (should-not (eq a copy1))
+    (should-not (eq a copy2)))
+  (let* ((a (record 'foo "a" (record 'bar "b")))
+         (copy1 (copy-tree a))
+         (copy2 (copy-tree a t)))
+    (should (equal a copy1))
+    (should (equal a copy2))
+    (should (eq a copy1))
+    (should-not (eq a copy2)))
+  (let* ((a ["a" "b" ["c" ["d"]]])
+         (copy1 (copy-tree a))
+         (copy2 (copy-tree a t)))
+    (should (equal a copy1))
+    (should (equal a copy2))
+    (should (eq a copy1))
+    (should-not (eq a copy2))))
+
 (provide 'subr-tests)
 ;;; subr-tests.el ends here