From 56f01a9a419a4c7c6e7a277bf08973ac08265dbc Mon Sep 17 00:00:00 2001
From: itchyny <itchyny@cybozu.co.jp>
Date: Sun, 9 Jul 2023 15:25:21 +0900
Subject: [PATCH] Fix empty regular expression matches (fix #2565)

---
 src/builtin.c   |  2 +-
 tests/onig.test | 22 +++++++++++++---------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/builtin.c b/src/builtin.c
index 0fd7554373..3cde686618 100644
--- a/src/builtin.c
+++ b/src/builtin.c
@@ -1002,7 +1002,7 @@ static jv f_match(jq_state *jq, jv input, jv regex, jv modifiers, jv testmode) {
             jv_string((char*)ebuf)));
       break;
     }
-  } while (global && start != end);
+  } while (global && start <= end);
   onig_region_free(region,1);
   region = NULL;
   if (region)
diff --git a/tests/onig.test b/tests/onig.test
index d49391fc09..fab41703a5 100644
--- a/tests/onig.test
+++ b/tests/onig.test
@@ -1,12 +1,16 @@
 # match builtin
 [match("( )*"; "g")]
 "abc"
-[{"offset":0, "length":0, "string":"", "captures":[]},{"offset":1, "length":0, "string":"", "captures":[]},{"offset":2, "length":0, "string":"", "captures":[]}]
+[{"offset":0, "length":0, "string":"", "captures":[]}, {"offset":1, "length":0, "string":"", "captures":[]}, {"offset":2, "length":0, "string":"", "captures":[]}, {"offset":3, "length":0, "string":"", "captures":[]}]
 
 [match("( )*"; "gn")]
 "abc"
 []
 
+[match(""; "g")]
+"ab"
+[{"offset":0,"length":0,"string":"","captures":[]},{"offset":1,"length":0,"string":"","captures":[]},{"offset":2,"length":0,"string":"","captures":[]}]
+
 [match("a"; "gi")]
 "āáàä"
 []
@@ -71,29 +75,29 @@ gsub("a";"b")
 "aaaaa"
 "bbbbb"
 
-gsub( "(.*)"; "";  "x")
+gsub("(.*)"; ""; "x")
 ""
 ""
 
-gsub( ""; "a";  "g")
+gsub(""; "a"; "g")
 ""
 "a"
 
-gsub( "^"; "";  "g")
+gsub("^"; ""; "g")
 "a"
 "a"
 
 
 # The following is a regression test and should not be construed as a requirement other than that execution should terminate:
-gsub( ""; "a";  "g")
+gsub(""; "a"; "g")
 "a"
-"aa"
+"aaa"
 
-gsub( "$"; "a";  "g")
+gsub("$"; "a"; "g")
 "a"
 "aa"
 
-gsub( "^"; "a")
+gsub("^"; "a")
 ""
 "a"
 
@@ -163,5 +167,5 @@ sub("(?<x>.)"; "\(.x)!")
 # splits and _nwise
 [splits("")]
 "ab"
-["","a","b"]
+["","a","b",""]