Fix rx regexp form with deprecated syntax

The argument of the rx `regexp` form is assumed to evaluate to a valid regexp, but certain kinds of deprecated but still accepted usage were not handled correctly, such as unescaped literal (special) characters: (rx "a" (regexp "*")) => "a*" which is wrong. Handle these cases; there is no extra trouble. * lisp/emacs-lisp/rx.el (rx--translate-regexp): Force bracketing of single special characters. * test/lisp/emacs-lisp/rx-tests.el (rx-regexp): Add test case.
flatwhatson · Feb 18, 2021 · 892db04 · 892db04
1 parent 8358637
commit 892db04
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diff --git a/lisp/emacs-lisp/rx.el b/lisp/emacs-lisp/rx.el
@@ -890,7 +890,7 @@ Return (REGEXP . PRECEDENCE)."
                                (* (or (seq "[:" (+ (any "a-z")) ":]")
                                       (not (any "]"))))
                                "]")
-                          anything
+                          (not (any "*+?^$[\\"))
                           (seq "\\"
                                (or anything
                                    (seq (any "sScC_") anything)

diff --git a/test/lisp/emacs-lisp/rx-tests.el b/test/lisp/emacs-lisp/rx-tests.el
@@ -391,6 +391,8 @@
   (let ((x "a*"))
     (should (equal (rx (regexp x) "b")
                    "\\(?:a*\\)b"))
+    (should (equal (rx "a" (regexp "*"))
+                   "a\\(?:*\\)"))
     (should (equal (rx "" (regexp x) (eval ""))
                    "a*"))))