From a690f6bf85225c34d3e336664d2437c16f7a7238 Mon Sep 17 00:00:00 2001
From: ph10 <ph10@2f5784b3-3f2a-0410-8824-cb99058d5e15>
Date: Tue, 7 Apr 2015 16:19:03 +0000
Subject: [PATCH] Fix pcretest loop for \K in lookbehind assertion.
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Upstream commit ported to 8.36:

commit c3579a7581cb8b3ca3c9617d63083afea29de646
Author: ph10 <ph10@2f5784b3-3f2a-0410-8824-cb99058d5e15>
Date:   Tue Apr 7 16:19:03 2015 +0000

    Fix pcretest loop for \K in lookbehind assertion.

    git-svn-id: svn://vcs.exim.org/pcre/code/trunk@1544 2f5784b3-3f2a-0410-8824-cb99058d5e15

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 pcretest.c           | 30 +++++++++++++++++++++++++++---
 testdata/testinput2  |  6 ++++++
 testdata/testinput5  |  6 ++++++
 testdata/testoutput2 | 28 ++++++++++++++++++++++++++++
 testdata/testoutput5 | 28 ++++++++++++++++++++++++++++
 5 files changed, 95 insertions(+), 3 deletions(-)

diff --git a/pcretest.c b/pcretest.c
index b8dc3c6..6e6ef48 100644
--- a/pcretest.c
+++ b/pcretest.c
@@ -5618,9 +5618,33 @@ while (!done)
         g_notempty = PCRE_NOTEMPTY_ATSTART | PCRE_ANCHORED;
         }
 
-      /* For /g, update the start offset, leaving the rest alone */
-
-      if (do_g) start_offset = use_offsets[1];
+      /* For /g, update the start offset, leaving the rest alone. There is a 
+      tricky case when \K is used in a positive lookbehind assertion. This can 
+      cause the end of the match to be less than or equal to the start offset. 
+      In this case we restart at one past the start offset. This may return the 
+      same match if the original start offset was bumped along during the 
+      match, but eventually the new start offset will hit the actual start 
+      offset. (In PCRE2 the true start offset is available, and this can be 
+      done better. It is not worth doing more than making sure we do not loop 
+      at this stage in the life of PCRE1.) */
+
+      if (do_g) 
+        {
+        if (g_notempty == 0 && use_offsets[1] <= start_offset)
+          {
+          if (start_offset >= len) break;  /* End of subject */ 
+          start_offset++;
+          if (use_utf)
+            {
+            while (start_offset < len)
+              {
+              if ((bptr[start_offset] & 0xc0) != 0x80) break;
+              start_offset++;
+              }
+            }
+          }  
+        else start_offset = use_offsets[1];
+        } 
 
       /* For /G, update the pointer and length */
 
diff --git a/testdata/testinput2 b/testdata/testinput2
index 0fc535a..f8fbced 100644
--- a/testdata/testinput2
+++ b/testdata/testinput2
@@ -4088,4 +4088,10 @@ backtracking verbs. --/
 
 "(?<=((?2))((?1)))"
 
+/(?<=\Ka)/g+
+    aaaaa
+
+/(?<=\Ka)/G+
+    aaaaa
+
 /-- End of testinput2 --/
diff --git a/testdata/testinput5 b/testdata/testinput5
index e36b09d..fe7218d 100644
--- a/testdata/testinput5
+++ b/testdata/testinput5
@@ -790,4 +790,10 @@
 
 /[b-d\x{200}-\x{250}]*[ae-h]?#[\x{200}-\x{250}]{0,8}[\x00-\xff]*#[\x{200}-\x{250}]+[a-z]/8BZ
 
+/(?<=\K\x{17f})/8g+
+    \x{17f}\x{17f}\x{17f}\x{17f}\x{17f}
+
+/(?<=\K\x{17f})/8G+
+    \x{17f}\x{17f}\x{17f}\x{17f}\x{17f}
+
 /-- End of testinput5 --/
diff --git a/testdata/testoutput2 b/testdata/testoutput2
index 45662a9..5233de4 100644
--- a/testdata/testoutput2
+++ b/testdata/testoutput2
@@ -14221,4 +14221,32 @@ No match
 "(?<=((?2))((?1)))"
 Failed: lookbehind assertion is not fixed length at offset 17
 
+/(?<=\Ka)/g+
+    aaaaa
+ 0: a
+ 0+ aaaa
+ 0: a
+ 0+ aaaa
+ 0: a
+ 0+ aaa
+ 0: a
+ 0+ aa
+ 0: a
+ 0+ a
+ 0: a
+ 0+ 
+
+/(?<=\Ka)/G+
+    aaaaa
+ 0: a
+ 0+ aaaa
+ 0: a
+ 0+ aaa
+ 0: a
+ 0+ aa
+ 0: a
+ 0+ a
+ 0: a
+ 0+ 
+
 /-- End of testinput2 --/
diff --git a/testdata/testoutput5 b/testdata/testoutput5
index 5c098e6..b338e23 100644
--- a/testdata/testoutput5
+++ b/testdata/testoutput5
@@ -1897,4 +1897,32 @@ Failed: disallowed Unicode code point (>= 0xd800 && <= 0xdfff) at offset 5
         End
 ------------------------------------------------------------------
 
+/(?<=\K\x{17f})/8g+
+    \x{17f}\x{17f}\x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}
+ 0: \x{17f}
+ 0+ 
+
+/(?<=\K\x{17f})/8G+
+    \x{17f}\x{17f}\x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}\x{17f}
+ 0: \x{17f}
+ 0+ \x{17f}
+ 0: \x{17f}
+ 0+ 
+
 /-- End of testinput5 --/
-- 
2.1.0