Package: Emacs
Version: 30.0.50


If I open a file `foo.tex` with a local variable setting of
`TeX-master: "paper.tex"` and that `paper.tex` file has a local
variable setting of `TeX-master: t`, I get the funny behavior that
Emacs first asks me whether to obey the `TeX-master: t` setting of
`paper.tex` before asking me whether to obey the `TeX-master:
"paper.tex"` setting of `foo.tex`, even though it obviously had to use
the `TeX-master: "paper.tex"` setting in order to decide to open the
`paper.tex` file (and ask me about its `TeX-master: t`).

The corresponding backtrace looks as below:

    Debugger entered--Lisp error: (minibuffer-quit)
      #<subr F616e6f6e796d6f75732d6c616d626461_anonymous_lambda_57>()
      read-char-from-minibuffer("Please type y, n, ! or i, or C-v/M-v to scroll: " (33 105 121 110 32))
      read-char-choice("Please type y, n, ! or i, or C-v/M-v to scroll: " (33 105 121 110 32))
      hack-local-variables-confirm(((TeX-master . t)) ((TeX-master . t)) nil nil)
      hack-local-variables-filter(((TeX-master . t)) nil)
      hack-local-variables(no-mode)
      run-mode-hooks(latex-mode-hook)
      latex-mode()
      set-auto-mode-0(latex-mode nil)
      set-auto-mode()
      normal-mode(t)
      after-find-file(nil nil)
      find-file-noselect-1(#<buffer paper.tex> ".../paper.tex" t nil ".../paper.tex" (3064599 65026))
      find-file-noselect("paper.tex" t)
      latexenc-find-file-coding-system((insert-file-contents ".../foo.tex" t nil nil nil))
      insert-file-contents(".../foo.tex" t)
      find-file-noselect-1(#<buffer foo.tex> ".../foo.tex" nil nil ".../foo.tex" (3064581 65026))
      find-file-noselect(".../foo.tex")
      command-line-1((".../foo.tex"))
      command-line()
      normal-top-level()

showing that the problem is that `latexenc-find-file-coding-system`
is the function that opens `paper.tex` before the users had a chance to
confirm that they think this is safe.

I suggest the patch below which makes `latexenc-find-file-coding-system`
use `safe-local-variable-p` before using a file-local setting, and also
adds corresponding `safe-local-variable` settings for `TeX-master` and
`tex-main-file`.


        Stefan