Commit 5f01af6c authored by Noam Postavsky's avatar Noam Postavsky

Use plain symbols for eieio type descriptors (Bug#29220)

Since Emacs 26, eieio objects use a class record (with circular
references) as the type descriptor of the object record.  This causes
problems when reading back an object from a string, because the class
record is not `eq' to the canonical one (which means that read objects
don't satisfy the foo-p predicate).
* lisp/emacs-lisp/eieio.el (make-instance): As a (partial) fix, set
the record's type descriptor to a plain symbol for the type descriptor
when eieio-backward-compatibility is non-nil (the default).
* lisp/emacs-lisp/eieio-core.el (eieio--object-class): Call
eieio--class-object on the type tag when eieio-backward-compatibility
is non-nil.
(eieio-object-p): Use eieio--object-class instead of
eieio--object-class-tag.
* test/lisp/emacs-lisp/eieio-tests/eieio-test-persist.el
(eieio-test-persist-hash-and-vector)
(eieio-test-persist-interior-lists): Make into functions.
(eieio-persist-hash-and-vector-backward-compatibility)
(eieio-persist-hash-and-vector-no-backward-compatibility)
(eieio-test-persist-interior-lists-backward-compatibility)
(eieio-test-persist-interior-lists-no-backward-compatibility): New
tests which call them, eieio-backward-compatibility let-bound.
parent 4b24b018
......@@ -117,9 +117,6 @@ Currently under control of this var:
(defsubst eieio--object-class-tag (obj)
(aref obj 0))
(defsubst eieio--object-class (obj)
(eieio--object-class-tag obj))
;;; Important macros used internally in eieio.
......@@ -132,6 +129,12 @@ Currently under control of this var:
(or (cl--find-class class) class)
class))
(defsubst eieio--object-class (obj)
(let ((tag (eieio--object-class-tag obj)))
(if eieio-backward-compatibility
(eieio--class-object tag)
tag)))
(defun class-p (x)
"Return non-nil if X is a valid class vector.
X can also be is a symbol."
......@@ -163,7 +166,7 @@ Return nil if that option doesn't exist."
(defun eieio-object-p (obj)
"Return non-nil if OBJ is an EIEIO object."
(and (recordp obj)
(eieio--class-p (eieio--object-class-tag obj))))
(eieio--class-p (eieio--object-class obj))))
(define-obsolete-function-alias 'object-p 'eieio-object-p "25.1")
......
......@@ -710,6 +710,9 @@ calls `initialize-instance' on that object."
;; Call the initialize method on the new object with the slots
;; that were passed down to us.
(initialize-instance new-object slots)
(when eieio-backward-compatibility
;; Use symbol as type descriptor, for backwards compatibility.
(aset new-object 0 class))
;; Return the created object.
new-object))
......
......@@ -277,7 +277,7 @@ persistent class.")
:type vector
:initarg :random-vector)))
(ert-deftest eieio-test-persist-hash-and-vector ()
(defun eieio-test-persist-hash-and-vector ()
(let* ((jane (make-instance 'person :name "Jane"))
(bob (make-instance 'person :name "Bob"))
(hans (make-instance 'person :name "Hans"))
......@@ -297,10 +297,18 @@ persistent class.")
(aset (car (slot-value class 'janitors)) 1 hans)
(aset (nth 1 (slot-value class 'janitors)) 1 dierdre)
(unwind-protect
;; FIXME: This should not error.
(should-error (persist-test-save-and-compare class))
(persist-test-save-and-compare class)
(delete-file (oref class file)))))
(ert-deftest eieio-persist-hash-and-vector-backward-compatibility ()
(let ((eieio-backward-compatibility t)) ; The default.
(eieio-test-persist-hash-and-vector)))
(ert-deftest eieio-persist-hash-and-vector-no-backward-compatibility ()
:expected-result :failed ;; Bug#29220.
(let ((eieio-backward-compatibility nil))
(eieio-test-persist-hash-and-vector)))
;; Extra quotation of lists inside other objects (Gnus registry), also
;; bug#29220.
......@@ -315,7 +323,7 @@ persistent class.")
:initarg :htab
:type hash-table)))
(ert-deftest eieio-test-persist-interior-lists ()
(defun eieio-test-persist-interior-lists ()
(let* ((thing (make-instance
'eieio-container
:vec [nil]
......@@ -335,8 +343,16 @@ persistent class.")
(setf (nth 2 (cadar alst)) john
(nth 2 (cadadr alst)) alexie)
(unwind-protect
;; FIXME: Should not error.
(should-error (persist-test-save-and-compare thing))
(persist-test-save-and-compare thing)
(delete-file (slot-value thing 'file)))))
(ert-deftest eieio-test-persist-interior-lists-backward-compatibility ()
(let ((eieio-backward-compatibility t)) ; The default.
(eieio-test-persist-interior-lists)))
(ert-deftest eieio-test-persist-interior-lists-no-backward-compatibility ()
:expected-result :failed ;; Bug#29220.
(let ((eieio-backward-compatibility nil))
(eieio-test-persist-interior-lists)))
;;; eieio-test-persist.el ends here
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