Prevent circular load.properties

avaje-config/src/main/java/io/avaje/config/InitialLoader.java

@@ -147,7 +147,9 @@ void loadViaCommandLine(String[] args) {
 
   private void loadCommandLineArg(String arg) {
     if (isValidExtension(arg)) {
-      loadViaPaths(arg);
+      for (String path : splitPaths(arg)) {
+        loadWithExtensionCheck(loadContext.eval(path));
+      }
     }
   }
 
@@ -193,7 +195,32 @@ private boolean loadTest() {
   private void loadViaIndirection() {
     String paths = loadContext.indirectLocation();
     if (paths != null) {
-      loadViaPaths(paths);
+      var stack = new ArrayDeque<String>();
+      splitAndAddPaths(stack, paths);
+      String path;
+      var sentinel = 0;
+      while ((path = stack.poll()) != null) {
+        loadWithExtensionCheck(loadContext.eval(path));
+        var newPath = loadContext.indirectLocation();
+        if (newPath == null) throw new IllegalStateException("truly impossible");
+        if (!paths.equals(newPath)) {
+          paths = newPath;
+          splitAndAddPaths(stack, paths);
+        }
+
+        sentinel++;
+        if (sentinel == 69) {
+          throw new IllegalStateException(
+              "Failed to resolve load.properties after 69 iterations. Perhaps Circular load.properties reference?");
+        }
+      }
+    }
+  }
+
+  private void splitAndAddPaths(ArrayDeque<String> stack, String paths) {
+    var split = splitPaths(paths);
+    for (int i = split.length - 1; i >= 0; i--) {
+      stack.addFirst(split[i]);
     }
   }
 
@@ -217,12 +244,6 @@ private void loadViaProfiles(Source source) {
     }
   }
 
-  private void loadViaPaths(String paths) {
-    for (String path : splitPaths(paths)) {
-      loadWithExtensionCheck(loadContext.eval(path));
-    }
-  }
-
   int size() {
     return loadContext.size();
   }

avaje-config/src/test/java/io/avaje/config/InitialLoaderTest.java

@@ -138,4 +138,16 @@ void load_withSuppressTestResource() {
       System.clearProperty("suppressTestResource");
     }
   }
+
+  @Test
+  void load_withLoadPropertyChain() {
+      InitialLoader loader = newInitialLoader();
+    loader.loadWithExtensionCheck("test-properties/chain/main.properties");
+    var properties = evalFor(loader.load());
+    assertThat(properties.get("value.a").value()).isEqualTo("true");
+    assertThat(properties.get("value.b").value()).isEqualTo("true");
+    assertThat(properties.get("value.c").value()).isEqualTo("true");
+    assertThat(properties.get("value.d").value()).isEqualTo("true");
+    assertThat(properties.get("override").value()).isEqualTo("d");
+  }
 }

avaje-config/src/test/resources/test-properties/chain/a.properties

@@ -0,0 +1,3 @@
+value.a=true
+override=a
+load.properties=test-properties/chain/c.properties 

avaje-config/src/test/resources/test-properties/chain/b.properties

@@ -0,0 +1,3 @@
+value.b=true
+override=b
+load.properties=test-properties/chain/c.properties 

avaje-config/src/test/resources/test-properties/chain/c.properties

@@ -0,0 +1,2 @@
+value.c=true
+override=c

avaje-config/src/test/resources/test-properties/chain/d.properties

@@ -0,0 +1,2 @@
+value.d=true
+override=d

avaje-config/src/test/resources/test-properties/chain/main.properties

@@ -0,0 +1 @@
+load.properties=test-properties/chain/a.properties test-properties/chain/b.properties, test-properties/chain/d.properties