bug#70541: track-changes-mode logs warnings (with input method, in Eglot buffer)

[Richard Copley <rcopley@gmail.com>]

(Moved here from https://github.com/joaotavora/eglot/discussions/1389)
On master.

The warning:

 »  Warning (emacs): Missing/incorrect calls to
‘before/after-change-functions’!!
Details logged to ‘track-changes--error-log’

... is raised, while editing in an Eglot buffer, with an input method.

* Ensure clangd is on the path
* Start editing a scratch file like this in C++ mode:

int main() {
  const char * s = "";
}

* Start Eglot (M-x eglot RET)
* Enable TeX input method (C-u C-\ TeX RET)
* Start typing the superscript alphabet into the string (^ a ^ b ^ c ^ d ...)

How far you get before the warning pops up seems to depend on timing.
In a run of this experiment from emacs -Q on master just now, I got as
far as k.

track-changes--error-log value:

((#3="z.cpp"
     ((t track-changes--recover-from-error nil nil)
      (t track-changes-fetch
(#1=
 #s(track-changes--tracker :signal
   eglot--track-changes-signal :state
   #s(track-changes--state :beg 50
   :end 1
   :before
   nil :next
   nil)
   :nobefore nil :immediate nil)
 #f(compiled-function (beg end before) #<bytecode
      0xae090d111a>))
nil)
      (t eglot--track-changes-fetch (#1#) nil)
      (t eglot--signal-textDocument/didChange nil nil)
      (t run-hooks (eglot--document-changed-hook) nil)
      (t #2=#f(compiled-function () #<bytecode 0x1bb90600ea83b761>)
nil nil)
      (t apply (#2# nil) nil)
      (t timer-event-handler ([t 0 0 500000 nil #2# nil idle 0 nil])
nil))
     [101 #6=(nil . self-insert-command) 94 102 #7=
 (nil . self-insert-command) 94 103 #8=
 (nil . self-insert-command) 94 104 #9=
 (nil . self-insert-command) 94 105 #10=
 (nil . self-insert-command) 94 106 #11=
 (nil . self-insert-command) 94 107
 (nil . self-insert-command)])
 (#3#
  ((t track-changes--recover-from-error nil nil)
   (t track-changes-fetch
      (#1#
       #f(compiled-function (beg end before) #<bytecode 0xae090d111a>))
      nil)
   (t eglot--track-changes-fetch (#1#) nil)
   (t eglot--signal-textDocument/didChange nil nil)
   (t run-hooks (eglot--document-changed-hook) nil)
   (t #5=#f(compiled-function () #<bytecode 0x1bb90600ea83b761>) nil
      nil)
   (t apply (#5# nil) nil)
   (t timer-event-handler ([t 0 0 500000 nil #5# nil idle 0 nil]) nil)
   (t read-key-sequence (nil nil nil t) nil)
   (t quail-start-translation (94) nil)
   (t quail-input-method (94) nil))
  [(nil . self-insert-command) 94 101 #6# 94 102 #7# 94 103 #8# 94 104
   #9# 94 105 #10# 94 106 #11# 94]))

Lossage:

 M-x     ;; execute-extended-command
 e     ;; self-insert-command
 g     ;; self-insert-command
 l     ;; self-insert-command
 o     ;; self-insert-command
 t     ;; self-insert-command
 <return>     ;; minibuffer-complete-and-exit
 C-u     ;; universal-argument
 C-\     ;; toggle-input-method
 T     ;; self-insert-command
 e     ;; self-insert-command
 X     ;; self-insert-command
 <return>     ;; minibuffer-complete-and-exit
 C-s     ;; isearch-forward
 "     ;; isearch-printing-char
 <with-input-method> ;; isearch-with-input-method
 <return>     ;; isearch-exit
 ^ a     ;; self-insert-command
 ^ b     ;; self-insert-command
 ^ c     ;; self-insert-command
 ^ d     ;; self-insert-command
 ^ e     ;; self-insert-command
 ^ f     ;; self-insert-command
 ^ g     ;; self-insert-command
 ^ h     ;; self-insert-command
 ^ i     ;; self-insert-command
 ^ j     ;; self-insert-command
 ^ k     ;; self-insert-command
 C-h l     ;; view-lossage

(Stefan notes:

If you want to silence these messages until the problem is fixed, you
can `(setq track-changes-record-errors nil)`.)