(risky-local-variable-p): New function.

(compile-command): Use `stringp' for `safe-local-variable' prop.
(hack-one-local-variable): Use `risky-local-variable-p'.

1 files changed, 17 insertions, 12 deletions

diff --git a/lisp/files.el b/lisp/files.el
index 9da9bd87875..be6cdfeb9b7 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -2057,16 +2057,21 @@ is specified, returning t if it is specified."
 (put 'mode-line-position 'risky-local-variable t)
 (put 'display-time-string 'risky-local-variable t)
 
-;; This one is safe because the user gets to check it before it is used.
-(put 'compile-command 'safe-local-variable t)
-
-(defun risky-local-variable-p (sym)
-  "Returns non-nil if SYM could be dangerous as a file-local variable."
-  (or (memq sym ignored-local-variables)
-      (get sym 'risky-local-variable)
-      (and (string-match "-hooks?$\\|-functions?$\\|-forms?$\\|-program$\\|-command$\\|-predicate$\\|font-lock-keywords$\\|font-lock-keywords-[0-9]+$\\|font-lock-syntactic-keywords$\\|-frame-alist$\\|-mode-alist$\\|-map$\\|-map-alist$"
-                         (symbol-name sym))
-           (not (get sym 'safe-local-variable)))))
+;; This case is safe because the user gets to check it before it is used.
+(put 'compile-command 'safe-local-variable 'stringp)
+
+(defun risky-local-variable-p (sym val)
+  "Non-nil if SYM could be dangerous as a file-local variable with value VAL."
+  (let ((safep (get sym 'safe-local-variable)))
+    (or (memq sym ignored-local-variables)
+        (get sym 'risky-local-variable)
+        (and (string-match "-hooks?$\\|-functions?$\\|-forms?$\\|-program$\\|-command$\\|-predicate$\\|font-lock-keywords$\\|font-lock-keywords-[0-9]+$\\|font-lock-syntactic-keywords$\\|-frame-alist$\\|-mode-alist$\\|-map$\\|-map-alist$"
+                           (symbol-name sym))
+             (not safep))
+        ;; If the safe-local-variable property isn't t or nil,
+        ;; then it must return non-nil on the proposed value to be safe.
+        (and (not (memq safep '(t nil)))
+             (not (funcall safep val))))))
 
 (defcustom safe-local-eval-forms nil
   "*Expressions that are considered \"safe\" in an `eval:' local variable.
@@ -2134,7 +2139,7 @@ is considered risky."
          nil)
         ;; "Setting" eval means either eval it or do nothing.
         ;; Likewise for setting hook variables.
-        ((risky-local-variable-p var)
+        ((risky-local-variable-p var val)
          ;; Permit evalling a put of a harmless property.
          ;; if the args do nothing tricky.
          (if (or (and (eq var 'eval)
@@ -2157,7 +2162,7 @@ is considered risky."
                  (save-excursion (eval val))
                (make-local-variable var)
                (set var val))
-           (message "Ignoring `eval:' in the local variables list")))
+           (message "Ignoring risky spec in the local variables list")))
         ;; Ordinary variable, really set it.
         (t (make-local-variable var)
            ;; Make sure the string has no text properties.