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regex.c (mutually_exclusive_p): Fix initial value of loop_beg

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* src/regex-emacs.c (mutually_exclusive_p): Don't pretend that pattern
position 0 has been checked already.

* test/src/regex-emacs-tests.el (regexp-tests-backtrack-optimization):
Add a corresponding regression test plus some other related tests
I had around.
This commit is contained in:
Stefan Monnier 2023-09-26 11:43:51 -04:00
parent 215bfb24dd
commit e88be844bf
2 changed files with 20 additions and 2 deletions
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2
src/regex-emacs.c
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@ -3941,7 +3941,7 @@ static bool
mutually_exclusive_p (struct re_pattern_buffer *bufp, re_char *p1,
re_char *p2)
{
return mutually_exclusive_aux (bufp, p1, p2, bufp->buffer, NULL);
return mutually_exclusive_aux (bufp, p1, p2, bufp->buffer - 1, NULL);
}
/* Matching routines. */

20
test/src/regex-emacs-tests.el
View file

@ -878,10 +878,28 @@ This evaluates the TESTS test cases from glibc."
(erase-buffer)
(insert (make-string 1000000 ?x) "=")
(goto-char (point-min))
;; Make sure we do perform the optimization (if we don't, the
;; below will burp with regexp-stack-overflow).
(should (looking-at "x*=*"))
(should (looking-at "x*\\(=\\|:\\)"))
(should (looking-at "x*\\(=\\|:\\)*"))
(should (looking-at "x*=*?"))))
(should (looking-at "x*=*?"))
(should (looking-at "x*\\(=*\\|h\\)*?"))
(should (looking-at "x*\\(=*\\|h\\)*"))
(should (looking-at "x*\\(=*?\\|h\\)*"))
(should (looking-at "x*\\(=*?\\|h\\)*?"))
(should (looking-at "x*\\(=*\\|h\\)+?"))
(should (looking-at "x*\\(=*\\|h\\)+"))
(should (looking-at "x*\\(=*?\\|h\\)+"))
(should (looking-at "x*\\(=*?\\|h\\)+?"))
(should (looking-at "x*\\(=+\\|h\\)+?"))
(should (looking-at "x*\\(=+\\|h\\)+"))
(should (looking-at "x*\\(=+?\\|h\\)+"))
(should (looking-at "x*\\(=+?\\|h\\)+?"))
;; Regression check for overly optimistic optimization.
(should (eq 0 (string-match "\\(ca*\\|ab\\)+d" "cabd")))
(should (string-match "\\(aa*\\|b\\)*c" "ababc"))
))
(ert-deftest regexp-tests-zero-width-assertion-repetition ()
;; Check compatibility behaviour with repetition operators after