From 5682a8a8aac39001f6868603bc81a462994c30bb Mon Sep 17 00:00:00 2001
From: Hugo van der Sanden <hv@crypt.org>
Date: Tue, 15 Sep 2020 14:02:54 +0100
Subject: [PATCH] assume worst-case for GOSUBs we don't analyse
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During study_chunk, under various conditions we avoid recursing into
a GOSUB. But we must avoid giving the enclosing scope the idea that
this GOSUB would match only an empty string, since that could trigger
wrong optimizations (eg CURLYX => CURLYM in the ticket).
So we mark the construct as infinite, as in the code branch where we
_do_ recurse into it.
Petr Písař: Ported from 9c256e3fab02bde17b249fc6a1057d34ca0a608d to
5.30.3.
Signed-off-by: Petr Písař <ppisar@redhat.com>
---
regcomp.c | 7 ++++++-
t/re/re_tests | 2 ++
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/regcomp.c b/regcomp.c
index 7426e83..df88311 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -5145,7 +5145,12 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
* might result in a minlen of 1 and not of 4,
* but this doesn't make us mismatch, just try a bit
* harder than we should.
- * */
+ *
+ * However we must assume this GOSUB is infinite, to
+ * avoid wrongly applying other optimizations in the
+ * enclosing scope - see GH 18096, for example.
+ */
+ is_inf = is_inf_internal = 1;
scan= regnext(scan);
continue;
}
diff --git a/t/re/re_tests b/t/re/re_tests
index d07c943..10867e0 100644
--- a/t/re/re_tests
+++ b/t/re/re_tests
@@ -2017,6 +2017,8 @@ AB\s+\x{100} AB \x{100}X y - -
/\x{30c3}?[\x{30a2}\x{30a4}\x{30a6}\x{30a8}\x{30aa}-\x{30e2}\x{30e4}\x{30e6}\x{30e8}-\x{30f4}](?:[\x{30e3}\x{30e5}\x{30e7}\x{30a1}\x{30a3}\x{30a5}\x{30a7}\x{30a9}])?\x{30fc}?\x{30f3}?/ \x{30de}\x{30fc}\x{30af}\x{30b5}\x{30fc}\x{30d3}\x{30b9} y $& \x{30de}\x{30fc} # part of [perl #133942
/[\x{3041}-\x{3093}]+/ \x{6f22}\x{5b57}\x{3001}\x{30ab}\x{30bf}\x{30ab}\x{30ca}\x{3001}\x{3072}\x{3089}\x{304c}\x{306a}\x{306e}\x{5165}\x{3063}\x{305f}String y $& \x{3072}\x{3089}\x{304c}\x{306a}\x{306e} # [perl #133978]
/(?:0)|(?:)(?:[1-9])/ q0 y $& 0 # [https://github.com/Perl/perl5/issues/17372]
+^((\w|<(\s)*(?1)(?3)*>)(?:(?3)*\+(?3)*(?2))*)(?3)*\+ a + b + <c + d> y $1 a + b # [GH #18096]
+^((\w|<(\s)*(?1)(?3)*>)(?:(?3)*\+(?3)*(?2))*)(?3)*\+ a + <b> + c y $1 a + <b> # [GH #18096]
# Keep these lines at the end of the file
# pat string y/n/etc expr expected-expr skip-reason comment
# vim: softtabstop=0 noexpandtab
--
2.25.4