From cf0d2663d32ca3c59c799a1499c3b3713ce5a4af Mon Sep 17 00:00:00 2001
From: Michael Ganss <michael.ganss@updatestar.com>
Date: Tue, 7 Jun 2022 12:18:06 +0200
Subject: [PATCH] Prevent stack overflow (fixes #329)

---
 .../xsd/simple/recursive.xsd                  | 49 +++++++++++++++++++
 XmlSchemaClassGenerator/ModelBuilder.cs       |  2 +-
 2 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 XmlSchemaClassGenerator.Tests/xsd/simple/recursive.xsd

diff --git a/XmlSchemaClassGenerator.Tests/xsd/simple/recursive.xsd b/XmlSchemaClassGenerator.Tests/xsd/simple/recursive.xsd
new file mode 100644
index 00000000..11832ad8
--- /dev/null
+++ b/XmlSchemaClassGenerator.Tests/xsd/simple/recursive.xsd
@@ -0,0 +1,49 @@
+<?xml version="1.0" encoding="utf-8"?>
+<schema id="Exceptions"
+    xmlns="http://www.w3.org/2001/XMLSchema"
+    attributeFormDefault="unqualified"
+    elementFormDefault="qualified"
+    targetNamespace="http://schemas.nsc.co.uk/exceptions"
+    xmlns:local="http://schemas.nsc.co.uk/exceptions">
+
+	<complexType name="ExceptionBase">
+		<attribute name="Message"/>
+	</complexType>
+
+	<complexType name="ArgumentNullException" >
+		<complexContent>
+			<extension base="local:ExceptionBase">
+				<attribute name="Argument"/>
+			</extension>
+		</complexContent>
+	</complexType>
+
+	<complexType name="InvalidOperationException" >
+		<complexContent>
+			<extension base="local:ExceptionBase">
+				<attribute name="Operation"/>
+			</extension>
+		</complexContent>
+	</complexType>
+
+	<complexType name="StackOverflowException" >
+		<complexContent>
+			<extension base="local:ExceptionBase">
+				<attribute name="Method"/>
+			</extension>
+		</complexContent>
+	</complexType>
+
+	<element name="Exception" type="local:ExceptionBase" abstract="true" substitutionGroup="local:Exception"/>
+	<element name="ArgumentNull" type="local:ArgumentNullException" substitutionGroup="local:Exception"/>
+	<element name="InvalidOperation" type="local:InvalidOperationException" substitutionGroup="local:Exception"/>
+	<element name="StackOverflow" type="local:StackOverflowException" substitutionGroup="local:Exception"/>
+
+	<element name="Exceptions">
+		<complexType>
+			<sequence>
+				<element minOccurs="0" maxOccurs="unbounded" ref="local:Exception"/>
+			</sequence>
+		</complexType>
+	</element>
+</schema>
\ No newline at end of file
diff --git a/XmlSchemaClassGenerator/ModelBuilder.cs b/XmlSchemaClassGenerator/ModelBuilder.cs
index 5db02dc8..b6b81073 100644
--- a/XmlSchemaClassGenerator/ModelBuilder.cs
+++ b/XmlSchemaClassGenerator/ModelBuilder.cs
@@ -380,7 +380,7 @@ private IEnumerable<Substitute> GetSubstitutedElements(XmlQualifiedName name)
         {
             if (SubstitutionGroups.TryGetValue(name, out var substitutes))
             {
-                foreach (var substitute in substitutes)
+                foreach (var substitute in substitutes.Where(s => s.Element.QualifiedName != name))
                 {
                     yield return substitute;
                     foreach (var recursiveSubstitute in GetSubstitutedElements(substitute.Element.QualifiedName))