pcre2/pcre2-10.33-Don-t-ignore-1-when-it-is-applied-to-a-parenthesized.patch

From 76d59bdbc2d30bad1d11e0490b767058dc33d39c Mon Sep 17 00:00:00 2001
From: ph10 <ph10@6239d852-aaf2-0410-a92c-79f79f948069>
Date: Wed, 19 Jun 2019 16:27:50 +0000
Subject: [PATCH] Don't ignore {1}+ when it is applied to a parenthesized item.
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git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@1111 6239d852-aaf2-0410-a92c-79f79f948069
Petr Písař: Ported to 10.33.

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 src/pcre2_compile.c  | 29 +++++++++++++++++++----------
 testdata/testinput1  | 14 ++++++++++++++
 testdata/testoutput1 | 18 ++++++++++++++++++
 3 files changed, 51 insertions(+), 10 deletions(-)

diff --git a/src/pcre2_compile.c b/src/pcre2_compile.c
index cd6fbea..c82c6ca 100644
--- a/src/pcre2_compile.c
+++ b/src/pcre2_compile.c
@@ -6723,10 +6723,6 @@ for (;; pptr++)
     reqvary = (repeat_min == repeat_max)? 0 : REQ_VARY;
     op_type = 0;
 
-    /* If the repeat is {1} we can ignore it. */
-
-    if (repeat_max == 1 && repeat_min == 1) goto END_REPEAT;
-
     /* Adjust first and required code units for a zero repeat. */
 
     if (repeat_min == 0)
@@ -6769,7 +6765,10 @@ for (;; pptr++)
     tempcode = previous;
     op_previous = *previous;
 
-    /* Now handle repetition for the different types of item. */
+    /* Now handle repetition for the different types of item. If the repeat
+    minimum and the repeat maximum are both 1, we can ignore the quantifier for
+    non-parenthesized items, as they have only one alternative. For anything in
+    parentheses, we must not ignore if {1} is possessive. */
 
     switch (op_previous)
       {
@@ -6783,6 +6782,7 @@ for (;; pptr++)
       case OP_CHARI:
       case OP_NOT:
       case OP_NOTI:
+      if (repeat_max == 1 && repeat_min == 1) goto END_REPEAT;
       op_type = chartypeoffset[op_previous - OP_CHAR];
 
       /* Deal with UTF characters that take up more than one code unit. */
@@ -6829,6 +6829,7 @@ for (;; pptr++)
         code = previous;
         goto END_REPEAT;
         }
+      if (repeat_max == 1 && repeat_min == 1) goto END_REPEAT;
 
       if (repeat_min == 0 && repeat_max == REPEAT_UNLIMITED)
         *code++ = OP_CRSTAR + repeat_type;
@@ -6863,6 +6864,8 @@ for (;; pptr++)
       repetition. */
 
       case OP_RECURSE:
+      if (repeat_max == 1 && repeat_min == 1 && !possessive_quantifier)
+        goto END_REPEAT;
 
       /* Generate unwrapped repeats for a non-zero minimum, except when the
       minimum is 1 and the maximum unlimited, because that can be handled with
@@ -6945,6 +6948,9 @@ for (;; pptr++)
         PCRE2_UCHAR *bralink = NULL;
         PCRE2_UCHAR *brazeroptr = NULL;
 
+        if (repeat_max == 1 && repeat_min == 1 && !possessive_quantifier)
+          goto END_REPEAT;
+
         /* Repeating a DEFINE group (or any group where the condition is always
         FALSE and there is only one branch) is pointless, but Perl allows the
         syntax, so we just ignore the repeat. */
@@ -7161,11 +7167,12 @@ for (;; pptr++)
         and SCRIPT_RUN groups at runtime, but in a different way.]
 
         Then, if the quantifier was possessive and the bracket is not a
-        conditional, we convert the BRA code to the POS form, and the KET code to
-        KETRPOS. (It turns out to be convenient at runtime to detect this kind of
-        subpattern at both the start and at the end.) The use of special opcodes
-        makes it possible to reduce greatly the stack usage in pcre2_match(). If
-        the group is preceded by OP_BRAZERO, convert this to OP_BRAPOSZERO.
+        conditional, we convert the BRA code to the POS form, and the KET code
+        to KETRPOS. (It turns out to be convenient at runtime to detect this
+        kind of subpattern at both the start and at the end.) The use of
+        special opcodes makes it possible to reduce greatly the stack usage in
+        pcre2_match(). If the group is preceded by OP_BRAZERO, convert this to
+        OP_BRAPOSZERO.
 
         Then, if the minimum number of matches is 1 or 0, cancel the possessive
         flag so that the default action below, of wrapping everything inside
@@ -7266,6 +7273,8 @@ for (;; pptr++)
         int prop_type, prop_value;
         PCRE2_UCHAR *oldcode;
 
+        if (repeat_max == 1 && repeat_min == 1) goto END_REPEAT;
+
         op_type = OP_TYPESTAR - OP_STAR;      /* Use type opcodes */
         mclength = 0;                         /* Not a character */
 
diff --git a/testdata/testinput1 b/testdata/testinput1
index 7b6918a..4d9ec5a 100644
--- a/testdata/testinput1
+++ b/testdata/testinput1
@@ -6351,4 +6351,18 @@ ef) x/x,mark
     acb
     abc     
 
+/(?:a|ab){1}+c/
+\= Expect no match
+    abc
+
+/(a|ab){1}+c/
+    abc
+    
+/(a+){1}+a/
+\= Expect no match
+    aaaa
+
+/(?(DEFINE)(a|ab))(?1){1}+c/
+    abc    
+
 # End of testinput1 
diff --git a/testdata/testoutput1 b/testdata/testoutput1
index d9f8c3b..fffb8ec 100644
--- a/testdata/testoutput1
+++ b/testdata/testoutput1
@@ -10063,4 +10063,22 @@ MK: 2
  0: a
 MK: 2
 
+/(?:a|ab){1}+c/
+\= Expect no match
+    abc
+No match
+
+/(a|ab){1}+c/
+    abc
+No match
+    
+/(a+){1}+a/
+\= Expect no match
+    aaaa
+No match
+
+/(?(DEFINE)(a|ab))(?1){1}+c/
+    abc    
+No match
+
 # End of testinput1 
-- 
2.20.1