Subject: Variable watcher notification bugs for "local if set" variables. Fix and ert in email to follow. (5 of 9)

From: Robert Burks <[email-masked]>
Date: Thu, 4 Apr 2024 04:46:07 -0400

(5 of 9)

Bug#00004 (no corresponding unlet notification and improper use of 'where'
            for local_if_set buffer local variables that shadow default.)

** Bug recreations are at the end

I have included a patch for this bug that applies on top of my four previous
submissions in the following email.  This bug occurs because an unaccounted
for
path in do_one_unbind calls set_default_internal.  Current regression
testing
only tests reaching the section of code my patch resides in from a direct
call
using set-default.  I have also included testing that covers all the
examples
provided in the next email.

It was the end of this bug's testing in which I unraveled even more
existing bugs
in which my work did not already solve.  The bug following this required
being
solved in conjunction with this bug.

Bug
Recreation------------------------------------------------------------------

-------------------------------------------
- LIS let and set in the same buffer. (shadows default)
-------------------------------------------
(defvar-local test 100)
test

(defvar results nil)
results

(add-variable-watcher 'test (lambda (&rest args)
                              (push args results)))
nil

(let ((test 99))
  (set 'test 66))
66

results
((test 100 set nil) (test 66 set #<buffer *scratch*>) (test 99 let #<buffer
*scratch*>))
;; there should be an unlet and the others should not have a
'where'!!!!!!!!!
;; Every let should have a corresponding unlet so a watcher function can
relieve
;; it's activity (if so desired) of watching its variable in a particular
buffer
;; and then resume it after the unlet occurs in that particular buffer.
;; Also, in this example the 'let' is acting on the default value as this
is a
;; 'let_shadows_default' case.  The 'let','set', and 'unlet' all act on the
default for
;; all variables that do not have their own value.  It should not have a
'where'.

-------------------------------------------
- LIS let and set in some buffer. (shadows default)
-------------------------------------------
(defvar-local test 5)
test

(defvar results nil)
results

(add-variable-watcher 'test (lambda (&rest args)
                              (push args results)))
nil

(with-temp-buffer
  (let ((test 99))
    (set 'test 66)))
66

results
((test 5 set nil) (test 66 set #<killed buffer>) (test 99 let #<killed
buffer>))