From 7b0f2cc7fa508dae7b2c66c74b335f4d0a2dbac3 Mon Sep 17 00:00:00 2001
From: Sylvain Jermini <sylvain.jermini@syjer.com>
Date: Wed, 25 Dec 2024 13:58:14 +0100
Subject: [PATCH] add circular inclusion check

---
 data/circular/circular-1.mjml                      |  5 +++++
 data/circular/circular-2.mjml                      |  5 +++++
 data/circular/include-circular.mjml                | 14 ++++++++++++++
 src/main/java/ch/digitalfondue/mjml4j/Mjml4j.java  |  5 ++++-
 .../digitalfondue/mjml4j/BaseComponentTests.java   |  2 +-
 .../digitalfondue/mjml4j/ComplexTemplateTests.java |  7 +++++++
 6 files changed, 36 insertions(+), 2 deletions(-)
 create mode 100644 data/circular/circular-1.mjml
 create mode 100644 data/circular/circular-2.mjml
 create mode 100644 data/circular/include-circular.mjml

diff --git a/data/circular/circular-1.mjml b/data/circular/circular-1.mjml
new file mode 100644
index 0000000..baeaa44
--- /dev/null
+++ b/data/circular/circular-1.mjml
@@ -0,0 +1,5 @@
+<mj-section css-class="bg-white">
+    <mj-column padding="32px 48px">
+        <mj-include path="circular-2.mjml" />
+    </mj-column>
+</mj-section>
\ No newline at end of file
diff --git a/data/circular/circular-2.mjml b/data/circular/circular-2.mjml
new file mode 100644
index 0000000..85e1930
--- /dev/null
+++ b/data/circular/circular-2.mjml
@@ -0,0 +1,5 @@
+<mj-section css-class="bg-white">
+    <mj-column padding="32px 48px">
+        <mj-include path="circular-1.mjml" />
+    </mj-column>
+</mj-section>
\ No newline at end of file
diff --git a/data/circular/include-circular.mjml b/data/circular/include-circular.mjml
new file mode 100644
index 0000000..059629a
--- /dev/null
+++ b/data/circular/include-circular.mjml
@@ -0,0 +1,14 @@
+<mjml>
+    <mj-body>
+
+        <mj-section css-class="bg-white">
+            <mj-column>
+                <mj-text padding="48px 48px 0 48px">
+                    <p>This is the Index!</p>
+                </mj-text>
+            </mj-column>
+        </mj-section>
+
+        <mj-include path="/circular/circular-1.mjml" />
+    </mj-body>
+</mjml>
\ No newline at end of file
diff --git a/src/main/java/ch/digitalfondue/mjml4j/Mjml4j.java b/src/main/java/ch/digitalfondue/mjml4j/Mjml4j.java
index 0ce1da2..919550e 100644
--- a/src/main/java/ch/digitalfondue/mjml4j/Mjml4j.java
+++ b/src/main/java/ch/digitalfondue/mjml4j/Mjml4j.java
@@ -501,7 +501,10 @@ private static BaseComponent handleInclude(Element element, BaseComponent parent
         try {
             resolvedPath = includeResolver.resolvePath(path, context.currentResourcePaths.peek());
             resource = includeResolver.readResource(resolvedPath);
-        } catch (IOException | IllegalStateException e) {
+            if (context.currentResourcePaths.contains(resolvedPath)) {
+                throw new IllegalStateException("Circular inclusion detected on file : " + resolvedPath);
+            }
+        } catch (IOException e) {
             resource = "<!-- mj-include fails to read file : " + path + " at " + resolvedPath + " -->";
             return new MjmlComponentRaw(element, parent, context, resource);
         }
diff --git a/src/test/java/ch/digitalfondue/mjml4j/BaseComponentTests.java b/src/test/java/ch/digitalfondue/mjml4j/BaseComponentTests.java
index a0ded53..49233dd 100644
--- a/src/test/java/ch/digitalfondue/mjml4j/BaseComponentTests.java
+++ b/src/test/java/ch/digitalfondue/mjml4j/BaseComponentTests.java
@@ -5,7 +5,7 @@
 import static ch.digitalfondue.mjml4j.Helpers.testTemplate;
 
 /**
- * Unit test for simple App.
+ * Unit test for base cases.
  */
 class BaseComponentTests {
 
diff --git a/src/test/java/ch/digitalfondue/mjml4j/ComplexTemplateTests.java b/src/test/java/ch/digitalfondue/mjml4j/ComplexTemplateTests.java
index 405e6ea..e3e0e14 100644
--- a/src/test/java/ch/digitalfondue/mjml4j/ComplexTemplateTests.java
+++ b/src/test/java/ch/digitalfondue/mjml4j/ComplexTemplateTests.java
@@ -1,5 +1,6 @@
 package ch.digitalfondue.mjml4j;
 
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 import static ch.digitalfondue.mjml4j.Helpers.testTemplate;
@@ -127,4 +128,10 @@ void testIncludeAbout() {
     void testDividerAttributeAll() {
         testTemplate("mj-divider-mj-all");
     }
+
+    @Test
+    void testCircularInclude() {
+        var t = Assertions.assertThrows(IllegalStateException.class, () -> testTemplate("circular/include-circular"));
+        Assertions.assertTrue(t.getMessage().startsWith("Circular inclusion detected on file"));
+    }
 }