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pcre2/pcre2-10.31-RC1-Fix-auto-possessification-bug-at-the-end-of-a-captur.patch

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From b70b8394e79360f92c87a169c1ba982a7e22d9d6 Mon Sep 17 00:00:00 2001
From: ph10 <ph10@6239d852-aaf2-0410-a92c-79f79f948069>
Date: Wed, 31 Jan 2018 17:53:56 +0000
Subject: [PATCH] Fix auto-possessification bug at the end of a capturing group
that is called recursively.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@912 6239d852-aaf2-0410-a92c-79f79f948069
Petr Písař: Ported to 10.31-RC1.
src/pcre2_auto_possess.c | 56 ++++++++++++++++++------
testdata/testinput1 | 30 +++++++++++++
testdata/testinput2 | 17 ++++++++
testdata/testoutput1 | 64 ++++++++++++++++++++++++++++
testdata/testoutput2 | 109 ++++++++++++++++++++++++++++++++++++++++++++++-
diff --git a/src/pcre2_auto_possess.c b/src/pcre2_auto_possess.c
index ad3543f..23275a2 100644
--- a/src/pcre2_auto_possess.c
+++ b/src/pcre2_auto_possess.c
@@ -558,47 +558,73 @@ for(;;)
continue;
}
+ /* At the end of a branch, skip to the end of the group. */
+
if (c == OP_ALT)
{
do code += GET(code, 1); while (*code == OP_ALT);
c = *code;
}
+ /* Inspect the next opcode. */
+
switch(c)
{
- case OP_END:
- case OP_KETRPOS:
- /* TRUE only in greedy case. The non-greedy case could be replaced by
- an OP_EXACT, but it is probably not worth it. (And note that OP_EXACT
- uses more memory, which we cannot get at this stage.) */
+ /* We can always possessify a greedy iterator at the end of the pattern,
+ which is reached after skipping over the final OP_KET. A non-greedy
+ iterator must never be possessified. */
+ case OP_END:
return base_list[1] != 0;
+ /* When an iterator is at the end of certain kinds of group we can inspect
+ what follows the group by skipping over the closing ket. Note that this
+ does not apply to OP_KETRMAX or OP_KETRMIN because what follows any given
+ iteration is variable (could be another iteration or could be the next
+ item). As these two opcodes are not listed in the next switch, they will
+ end up as the next code to inspect, and return FALSE by virtue of being
+ unsupported. */
+
case OP_KET:
- /* If the bracket is capturing, and referenced by an OP_RECURSE, or
- it is an atomic sub-pattern (assert, once, etc.) the non-greedy case
- cannot be converted to a possessive form. */
+ case OP_KETRPOS:
+ /* The non-greedy case cannot be converted to a possessive form. */
if (base_list[1] == 0) return FALSE;
+ /* If the bracket is capturing it might be referenced by an OP_RECURSE
+ so its last iterator can never be possessified if the pattern contains
+ recursions. (This could be improved by keeping a list of group numbers that
+ are called by recursion.) */
+
switch(*(code - GET(code, 1)))
{
+ case OP_CBRA:
+ case OP_SCBRA:
+ case OP_CBRAPOS:
+ case OP_SCBRAPOS:
+ if (cb->had_recurse) return FALSE;
+ break;
+
+ /* Atomic sub-patterns and assertions can always auto-possessify their
+ last iterator. However, if the group was entered as a result of checking
+ a previous iterator, this is not possible. */
+
case OP_ASSERT:
case OP_ASSERT_NOT:
case OP_ASSERTBACK:
case OP_ASSERTBACK_NOT:
case OP_ONCE:
- /* Atomic sub-patterns and assertions can always auto-possessify their
- last iterator. However, if the group was entered as a result of checking
- a previous iterator, this is not possible. */
-
return !entered_a_group;
}
+ /* Skip over the bracket and inspect what comes next. */
+
code += PRIV(OP_lengths)[c];
continue;
+ /* Handle cases where the next item is a group. */
+
case OP_ONCE:
case OP_BRA:
case OP_CBRA:
@@ -637,11 +663,15 @@ for(;;)
code += PRIV(OP_lengths)[c];
continue;
+ /* The next opcode does not need special handling; fall through and use it
+ to see if the base can be possessified. */
+
default:
break;
}
- /* Check for a supported opcode, and load its properties. */
+ /* We now have the next appropriate opcode to compare with the base. Check
+ for a supported opcode, and load its properties. */
code = get_chr_property_list(code, utf, cb->fcc, list);
if (code == NULL) return FALSE; /* Unsupported */
diff --git a/testdata/testinput1 b/testdata/testinput1
index 756b4af..9a9c5fd 100644
--- a/testdata/testinput1
+++ b/testdata/testinput1
@@ -6159,4 +6159,34 @@ ef) x/x,mark
/((?<=((*ACCEPT))X)\1?Y(*ACCEPT))\1/
XYYZ
+/(?(DEFINE)(?<optional_a>a?)X)^(?&optional_a)a$/
+ aa
+ a
+
+/^(a?)b(?1)a/
+ abaa
+ aba
+ baa
+ ba
+
+/^(a?)+b(?1)a/
+ abaa
+ aba
+ baa
+ ba
+
+/^(a?)++b(?1)a/
+ abaa
+ aba
+ baa
+ ba
+
+/^(a?)+b/
+ b
+ ab
+ aaab
+
+/(?=a+)a(a+)++b/
+ aab
+
# End of testinput1
diff --git a/testdata/testinput2 b/testdata/testinput2
index 2c2334c..5d3a80e 100644
--- a/testdata/testinput2
+++ b/testdata/testinput2
@@ -5412,4 +5412,21 @@ a)"xI
\= Expect no match
\na
+# These tests are matched in test 1 as they are Perl compatible. Here we are
+# looking at what does and does not get auto-possessified.
+
+/(?(DEFINE)(?<optional_a>a?))^(?&optional_a)a$/B
+
+/(?(DEFINE)(?<optional_a>a?)X)^(?&optional_a)a$/B
+
+/^(a?)b(?1)a/B
+
+/^(a?)+b(?1)a/B
+
+/^(a?)++b(?1)a/B
+
+/^(a?)+b/B
+
+/(?=a+)a(a+)++b/B
+
# End of testinput2
diff --git a/testdata/testoutput1 b/testdata/testoutput1
index 7cf647e..9c55be9 100644
--- a/testdata/testoutput1
+++ b/testdata/testoutput1
@@ -9758,4 +9758,68 @@ No match
1: Y
2:
+/(?(DEFINE)(?<optional_a>a?)X)^(?&optional_a)a$/
+ aa
+ 0: aa
+ a
+ 0: a
+
+/^(a?)b(?1)a/
+ abaa
+ 0: abaa
+ 1: a
+ aba
+ 0: aba
+ 1: a
+ baa
+ 0: baa
+ 1:
+ ba
+ 0: ba
+ 1:
+
+/^(a?)+b(?1)a/
+ abaa
+ 0: abaa
+ 1:
+ aba
+ 0: aba
+ 1:
+ baa
+ 0: baa
+ 1:
+ ba
+ 0: ba
+ 1:
+
+/^(a?)++b(?1)a/
+ abaa
+ 0: abaa
+ 1:
+ aba
+ 0: aba
+ 1:
+ baa
+ 0: baa
+ 1:
+ ba
+ 0: ba
+ 1:
+
+/^(a?)+b/
+ b
+ 0: b
+ 1:
+ ab
+ 0: ab
+ 1:
+ aaab
+ 0: aaab
+ 1:
+
+/(?=a+)a(a+)++b/
+ aab
+ 0: aab
+ 1: a
+
# End of testinput1
diff --git a/testdata/testoutput2 b/testdata/testoutput2
index f783320..fcaac8f 100644
--- a/testdata/testoutput2
+++ b/testdata/testoutput2
@@ -12701,7 +12701,7 @@ Subject length lower bound = 5
Ket
a
CBraPos 1
- a++
+ a+
KetRpos
a
Ket
@@ -16468,6 +16468,113 @@ No match
\na
No match
+# These tests are matched in test 1 as they are Perl compatible. Here we are
+# looking at what does and does not get auto-possessified.
+
+/(?(DEFINE)(?<optional_a>a?))^(?&optional_a)a$/B
+------------------------------------------------------------------
+ Bra
+ Cond
+ Cond false
+ CBra 1
+ a?
+ Ket
+ Ket
+ ^
+ Recurse
+ a
+ $
+ Ket
+ End
+------------------------------------------------------------------
+
+/(?(DEFINE)(?<optional_a>a?)X)^(?&optional_a)a$/B
+------------------------------------------------------------------
+ Bra
+ Cond
+ Cond false
+ CBra 1
+ a?
+ Ket
+ X
+ Ket
+ ^
+ Recurse
+ a
+ $
+ Ket
+ End
+------------------------------------------------------------------
+
+/^(a?)b(?1)a/B
+------------------------------------------------------------------
+ Bra
+ ^
+ CBra 1
+ a?
+ Ket
+ b
+ Recurse
+ a
+ Ket
+ End
+------------------------------------------------------------------
+
+/^(a?)+b(?1)a/B
+------------------------------------------------------------------
+ Bra
+ ^
+ SCBra 1
+ a?
+ KetRmax
+ b
+ Recurse
+ a
+ Ket
+ End
+------------------------------------------------------------------
+
+/^(a?)++b(?1)a/B
+------------------------------------------------------------------
+ Bra
+ ^
+ SCBraPos 1
+ a?
+ KetRpos
+ b
+ Recurse
+ a
+ Ket
+ End
+------------------------------------------------------------------
+
+/^(a?)+b/B
+------------------------------------------------------------------
+ Bra
+ ^
+ SCBra 1
+ a?
+ KetRmax
+ b
+ Ket
+ End
+------------------------------------------------------------------
+
+/(?=a+)a(a+)++b/B
+------------------------------------------------------------------
+ Bra
+ Assert
+ a++
+ Ket
+ a
+ CBraPos 1
+ a++
+ KetRpos
+ b
+ Ket
+ End
+------------------------------------------------------------------
+
# End of testinput2
Error -65: PCRE2_ERROR_BADDATA (unknown error number)
Error -62: bad serialized data
--
2.13.6
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