From 18934137ddfd765025e73b2eb1a1bb83ee5fc03b Mon Sep 17 00:00:00 2001
From: drh <>
Date: Mon, 18 Jul 2022 13:10:53 +0000
Subject: [PATCH] Fix a problem in the REGEXP extension for the {M,N} construct
 where M is zero. See [forum:/forumpost/8694e55a2c29963c|forum post
 8694e55a2c29963c] for more information.

FossilOrigin-Name: af15bb75306a4b94593b8431a34768b3de3d6689293e85ca02db16bf3e9f39e2
---
 ext/misc/regexp.c |  1 +
 manifest          | 14 +++++++-------
 manifest.uuid     |  2 +-
 test/regexp1.test | 11 +++++++++++
 4 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/ext/misc/regexp.c b/ext/misc/regexp.c
index 54c505233d..8a3e13115f 100644
--- a/ext/misc/regexp.c
+++ b/ext/misc/regexp.c
@@ -568,6 +568,7 @@ static const char *re_subcompile_string(ReCompiled *p){
         if( m==0 ){
           if( n==0 ) return "both m and n are zero in '{m,n}'";
           re_insert(p, iPrev, RE_OP_FORK, sz+1);
+          iPrev++;
           n--;
         }else{
           for(j=1; j<m; j++) re_copy(p, iPrev, sz);
diff --git a/manifest b/manifest
index e2ba6ba112..643970b2d4 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Enhance\sthe\sext/misc/regexp.c\scode\sso\sthat\swhen\sit\sis\scompiled\swith\nSQLITE_DEBUG,\sa\snew\sfunction\snamed\sregexp_bytecode()\sis\savailable\sthat\nprints\sout\sthe\scompiled\sNFA\sas\shuman-readable\stext,\sfor\sdebugging\spurposes.
-D 2022-07-18T11:44:16.316
+C Fix\sa\sproblem\sin\sthe\sREGEXP\sextension\sfor\sthe\s{M,N}\sconstruct\swhere\sM\sis\szero.\nSee\s[forum:/forumpost/8694e55a2c29963c|forum\spost\s8694e55a2c29963c]\sfor\smore\ninformation.
+D 2022-07-18T13:10:53.496
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -334,7 +334,7 @@ F ext/misc/normalize.c bd84355c118e297522aba74de34a4fd286fc775524e0499b14473918d
 F ext/misc/percentile.c b9086e223d583bdaf8cb73c98a6539d501a2fc4282654adbfea576453d82e691
 F ext/misc/prefixes.c 0f4f8cff5aebc00a7e3ac4021fd59cfe1a8e17c800ceaf592859ecb9cbc38196
 F ext/misc/qpvtab.c 09738419e25f603a35c0ac8bd0a04daab794f48d08a9bc07a6085b9057b99009
-F ext/misc/regexp.c 554bbbc06980fac640618da2401b9b1a5da722f60fbc9ecd0de0244c96173a23
+F ext/misc/regexp.c 76693a7c74555947fb90bda00082b0a67ff40ac08b78c022b24623d85772fb75
 F ext/misc/remember.c add730f0f7e7436cd15ea3fd6a90fd83c3f706ab44169f7f048438b7d6baa69c
 F ext/misc/rot13.c 51ac5f51e9d5fd811db58a9c23c628ad5f333c173f1fc53c8491a3603d38556c
 F ext/misc/scrub.c 2a44b0d44c69584c0580ad2553f6290a307a49df4668941d2812135bfb96a946
@@ -1343,7 +1343,7 @@ F test/randexpr1.test eda062a97e60f9c38ae8d806b03b0ddf23d796df
 F test/rbu.test 168573d353cd0fd10196b87b0caa322c144ef736
 F test/rdonly.test 64e2696c322e3538df0b1ed624e21f9a23ed9ff8
 F test/recover.test ccb8c2623902a92ebb76770edd075cb4f75a4760bb7afde38026572c6e79070d
-F test/regexp1.test 611adedda9ab00c86a14e2a4becf4086ed712e83d86f576a884d21795213f16b
+F test/regexp1.test d5d019b599d04475b1e6291ff87befeb6b6436fe8a5c96df0cd1afdd4c521860
 F test/regexp2.test 55ed41da802b0e284ac7e2fe944be3948f93ff25abbca0361a609acfed1368b5
 F test/reindex.test cd9d6021729910ece82267b4f5e1b5ac2911a7566c43b43c176a6a4732e2118d
 F test/releasetest_data.tcl 11ba48a21ed1c808147b0e77c6e93d204577f4327ffe6d7c3b34cd3c01eac3a2
@@ -1980,8 +1980,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 449799e2d5902464540e8fda53ab429e0518278dab3b17c86911759114cddea0
-R c5fe187a7b0d702467f87ef01664ca12
+P cb5c08978fe8f074e6ae16953575213709e98b8bbae4359e0d2e6de67a7ea9e5
+R 37f87d1133b807cf92a2fb764578dc08
 U drh
-Z c7627cc664c2932a41026727705de830
+Z e81c08e4815bfae8cfa31e84be51c0a0
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 5a0612c077..65040fd41b 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-cb5c08978fe8f074e6ae16953575213709e98b8bbae4359e0d2e6de67a7ea9e5
\ No newline at end of file
+af15bb75306a4b94593b8431a34768b3de3d6689293e85ca02db16bf3e9f39e2
\ No newline at end of file
diff --git a/test/regexp1.test b/test/regexp1.test
index fa941af53b..d7a12ceed1 100644
--- a/test/regexp1.test
+++ b/test/regexp1.test
@@ -279,5 +279,16 @@ do_execsql_test regexp1-4.10 {SELECT 'xaby' REGEXP 'a(cd|b$|e)';} {0}
 do_execsql_test regexp1-4.11 {SELECT 'xacd' REGEXP 'a(cd|b$|e)';} {1}
 do_execsql_test regexp1-4.12 {SELECT 'xacdy' REGEXP 'a(cd|b$|e)';} {1}
 
+# 2022-07-18
+# https://sqlite.org/forum/forumpost/57cbaf1d0e
+# Incorrect bytecode for {M,N} when M is zero.
+#
+do_execsql_test regexp1-5.1 {SELECT 'fooX' REGEXP '^[a-z][a-z0-9]{0,30}$';} {0}
+do_execsql_test regexp1-5.2 {SELECT 'fooX' REGEXP '^[a-z][a-z0-9]{0,30}X$';} {1}
+do_execsql_test regexp1-5.3 {SELECT 'fooX' REGEXP '^[a-z][a-z0-9]{0,2}X$';} {1}
+do_execsql_test regexp1-5.4 {SELECT 'foooX' REGEXP '^[a-z][a-z0-9]{0,2}X$';} {0}
+do_execsql_test regexp1-5.5 {SELECT 'foooX' REGEXP '^[a-z][a-z0-9]{0,3}X$';} {1}
+
+
 
 finish_test