Detect infinite loop/crash

pom.xml

@@ -150,6 +150,14 @@
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
 

src/main/java/de/neuland/jade4j/model/JadeModel.java

@@ -11,8 +11,11 @@
 import java.util.Map;
 import java.util.Set;
 
+import de.neuland.jade4j.exceptions.JadeCompilerException;
 import de.neuland.jade4j.filter.Filter;
 import de.neuland.jade4j.parser.node.MixinNode;
+import de.neuland.jade4j.parser.node.Node;
+import de.neuland.jade4j.template.JadeTemplate;
 
 public class JadeModel implements Map<String, Object> {
 
@@ -22,6 +25,10 @@ public class JadeModel implements Map<String, Object> {
 	private Map<String, MixinNode> mixins = new HashMap<String, MixinNode>();
 	private Map<String, Filter> filter = new HashMap<String, Filter>();
 
+	// to detect infinite loop
+	private Map<String, Integer> visited = new HashMap<String, Integer>();
+	private Integer MAX_VISITED = 100;
+
 	public JadeModel(Map<String, Object> defaults) {
 		Map<String, Object> rootScope = new HashMap<String, Object>();
 		scopes.add(rootScope);
@@ -50,6 +57,16 @@ public MixinNode getMixin(String name) {
 		return mixins.get(name);
 	}
 
+	public void visit(Node node, JadeTemplate template) {
+		String visitId = node.getFileName()+":"+node.getLineNumber();
+		Integer ct = visited.getOrDefault(visitId, 0) +1;
+		if (ct > MAX_VISITED) {
+			String error = "Potential infinite loop: "+visitId+" has been visited more then "+MAX_VISITED+" times!";
+			throw new JadeCompilerException(node, template.getTemplateLoader(), error);
+		}
+		visited.put(visitId, ct);
+	}
+
 	@Override
 	public void clear() {
 		scopes.clear();

src/main/java/de/neuland/jade4j/parser/BlockCommentNode.java

@@ -9,6 +9,7 @@ public class BlockCommentNode extends CommentNode {
 
 	@Override
 	public void execute(IndentWriter writer, JadeModel model, JadeTemplate template) throws JadeCompilerException {
+		model.visit(this, template);
 		if (!isBuffered()) {
 			return;
 		}

src/main/java/de/neuland/jade4j/parser/node/BlockNode.java

@@ -12,6 +12,7 @@ public class BlockNode extends Node {
 	private String mode;
 
 	public void execute(IndentWriter writer, JadeModel model, JadeTemplate template) throws JadeCompilerException {
+		model.visit(this, template);
 		for (Node node : getNodes()) {
 			node.execute(writer, model, template);
 		}

src/main/java/de/neuland/jade4j/parser/node/ConditionalNode.java

@@ -16,6 +16,7 @@ public class ConditionalNode extends Node {
 
 	@Override
 	public void execute(IndentWriter writer, JadeModel model, JadeTemplate template) throws JadeCompilerException {
+		model.visit(this, template);
 		for (IfConditionNode conditionNode : this.conditions) {
 			try {
 				if (conditionNode.isDefault() || checkCondition(model, conditionNode.getValue()) ^ conditionNode.isInverse()) {

src/main/java/de/neuland/jade4j/parser/node/IfConditionNode.java

@@ -17,6 +17,7 @@ public IfConditionNode(String condition, int lineNumber) {
 
 	@Override
 	public void execute(IndentWriter writer, JadeModel model, JadeTemplate template) throws JadeCompilerException {
+		model.visit(this, template);
 		block.execute(writer, model, template);
 	}
 

src/main/java/de/neuland/jade4j/parser/node/MixinInjectNode.java

@@ -16,6 +16,7 @@ public class MixinInjectNode extends AttributedNode {
 
 	@Override
 	public void execute(IndentWriter writer, JadeModel model, JadeTemplate template) throws JadeCompilerException {
+		model.visit(this, template);
 		MixinNode mixin = model.getMixin(getName());
 		if (mixin == null) {
 			throw new JadeCompilerException(this, template.getTemplateLoader(), "mixin " + getName() + " is not defined");

src/main/java/de/neuland/jade4j/parser/node/TagNode.java

@@ -56,6 +56,7 @@ public boolean hasCodeNode() {
 
     @Override
     public void execute(IndentWriter writer, JadeModel model, JadeTemplate template) throws JadeCompilerException {
+        model.visit(this, template);
         writer.newline();
         writer.append("<");
         writer.append(name);