[elpa] externals/relint bafb104 3/3: Fix regexp stack overflow when scanning big files

[ELPA Syncer]

branch: externals/relint
commit bafb10445fcf00d0600097e40ac94c885878d922
Author: Mattias Engdegård <mattiase@acm.org>
Commit: Mattias Engdegård <mattiase@acm.org>

    Fix regexp stack overflow when scanning big files
    
    This error occurred while scanning a file in phps-mode
    (phps-mode-parser.el, 17 MiB, about 190000 strings).
    The NFA engine in Emacs is simply not clever enough to avoid stack
    build-up here; the smart-jump hack only works in more limited cases.
---
 relint-test.el | 19 +++++++++++++++++++
 relint.el      | 10 +++++-----
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/relint-test.el b/relint-test.el
index 2e00392..8b4bd66 100644
--- a/relint-test.el
+++ b/relint-test.el
@@ -146,3 +146,22 @@ and a path."
                      ("In call to string-match: Unterminated character 
alternative"
                       125 nil "[xy" nil error)))))
       (kill-buffer buf))))
+
+(ert-deftest relint-buffer-huge ()
+  ;; Regression test for regexp stack overflow in the scan for ineffective
+  ;; backslashes.
+  (should (equal
+           (with-temp-buffer
+             (emacs-lisp-mode)
+             (insert "(message \"hello\\? anyone?\")\n")
+             (insert "(defconst my-const '(")
+             (dotimes (i 200000)
+               (insert (format "%d " i)))
+             (insert "))\n")
+             (insert "(message \"goodbye\\! everyone!\")\n")
+             (let ((text-quoting-style 'grave))
+               (relint-buffer (current-buffer))))
+           '(("Ineffective string escape `\\?'" 16 nil nil nil warning)
+             ("Ineffective string escape `\\!'" 1288960 nil nil nil 
warning)))))
+
+(provide 'relint-test)
diff --git a/relint.el b/relint.el
index be8b254..0108e11 100644
--- a/relint.el
+++ b/relint.el
@@ -2260,11 +2260,11 @@ STRING-START is the start of the string literal (first 
double quote)."
   "Check for misplaced backslashes in the current buffer."
   (goto-char (point-min))
   (while (not (eobp))
-    (when (looking-at (rx (1+ (or (seq "?" (or (seq ?\\ anything)
-                                               (not (any ?\\))))
-                                  (seq "\\" anything)
-                                  (seq ";" (0+ nonl))
-                                  (not (any ?\" ?\; ?? ?\\))))))
+    (while (looking-at (rx (or (+ (not (any ?\" ?\; ?? ?\\)))
+                               (seq ";" (0+ nonl))
+                               (seq "?" (or (seq ?\\ anything)
+                                            (not (any ?\\))))
+                               (seq "\\" anything))))
       (goto-char (match-end 0)))
     (when (eq (following-char) ?\")
       (let ((string-start (point)))