Remove purespace fix from cl-preloaded.el

* lisp/emacs-lisp/cl-preloaded.el (cl-struct-define): Remove fix for
purespace.  This effectively reverts Stefan Monnier's commit
e785c74d3a.
This commit is contained in:
Stefan Kangas 2024-12-09 21:34:57 +01:00
parent d6aeb1a260
commit bb64e9464c

View file

@ -183,20 +183,7 @@
(add-to-list 'current-load-list `(define-type . ,name))
(cl--struct-register-child parent-class tag)
(unless (or (eq named t) (eq tag name))
;; We used to use `defconst' instead of `set' but that
;; has a side-effect of purecopying during the dump, so that the
;; class object stored in the tag ends up being a *copy* of the
;; one stored in the `cl--class' property! We could have fixed
;; this needless duplication by using the purecopied object, but
;; that then breaks down a bit later when we modify the
;; cl-structure-class class object to close the recursion
;; between cl-structure-object and cl-structure-class (because
;; modifying purecopied objects is not allowed. Since this is
;; done during dumping, we could relax this rule and allow the
;; modification, but it's cumbersome).
;; So in the end, it's easier to just avoid the duplication by
;; avoiding the use of the purespace here.
(set tag class)
(eval `(defconst ,tag ',class) t)
;; In the cl-generic support, we need to be able to check
;; if a vector is a cl-struct object, without knowing its particular type.
;; So we use the (otherwise) unused function slots of the tag symbol