From e9e6bce80a7a33924742cc3f9373accb26ea0c4b Mon Sep 17 00:00:00 2001
From: Rasmus Lerchedahl Petersen <yoff@github.com>
Date: Wed, 16 Aug 2023 11:49:23 +0200
Subject: [PATCH] shared: handle empty groups in delta

---
 shared/regex/codeql/regex/nfa/NfaUtils.qll | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/shared/regex/codeql/regex/nfa/NfaUtils.qll b/shared/regex/codeql/regex/nfa/NfaUtils.qll
index a951820bda1..2b14fe28aca 100644
--- a/shared/regex/codeql/regex/nfa/NfaUtils.qll
+++ b/shared/regex/codeql/regex/nfa/NfaUtils.qll
@@ -760,6 +760,12 @@ module Make<RegexTreeViewSig TreeImpl> {
     or
     exists(RegExpGroup grp | lbl = Epsilon() | q1 = before(grp) and q2 = before(grp.getChild(0)))
     or
+    exists(RegExpGroup grp | lbl = Epsilon() |
+      not exists(grp.getAChild()) and
+      q1 = before(grp) and
+      q2 = before(grp.getSuccessor())
+    )
+    or
     exists(EffectivelyStar star | lbl = Epsilon() |
       q1 = before(star) and q2 = before(star.getChild(0))
       or