From 031340795ceb3457bee14954fff008ccd0b62f2f Mon Sep 17 00:00:00 2001
From: Mike Barry <msb5014@gmail.com>
Date: Sat, 28 Sep 2024 16:41:30 -0400
Subject: [PATCH] fix merge order

---
 planetiler-core/pom.xml                          |  5 +++++
 .../com/onthegomap/planetiler/util/YAML.java     | 16 ++++++++++------
 .../com/onthegomap/planetiler/util/YamlTest.java |  9 +++++----
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/planetiler-core/pom.xml b/planetiler-core/pom.xml
index eef160c5d5..0ff8b2ce2a 100644
--- a/planetiler-core/pom.xml
+++ b/planetiler-core/pom.xml
@@ -129,6 +129,11 @@
       <groupId>org.snakeyaml</groupId>
       <artifactId>snakeyaml-engine</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.yaml</groupId>
+      <artifactId>snakeyaml</artifactId>
+      <version>2.3</version>
+    </dependency>
     <dependency>
       <groupId>io.prometheus</groupId>
       <artifactId>simpleclient</artifactId>
diff --git a/planetiler-core/src/main/java/com/onthegomap/planetiler/util/YAML.java b/planetiler-core/src/main/java/com/onthegomap/planetiler/util/YAML.java
index b051dc5138..0a504a0ef2 100644
--- a/planetiler-core/src/main/java/com/onthegomap/planetiler/util/YAML.java
+++ b/planetiler-core/src/main/java/com/onthegomap/planetiler/util/YAML.java
@@ -51,11 +51,11 @@ private static void handleMergeOperator(Object parsed) {
     if (parsed instanceof Map<?, ?> map) {
       Object toMerge = map.remove("<<");
       if (toMerge != null) {
-        Map<?, ?> orig = new LinkedHashMap<>(map);
+        var orig = new LinkedHashMap<>(map);
         // to preserve the map key order we insert the merged operator objects first, then the original ones
         map.clear();
-        mergeInto(map, toMerge);
-        mergeInto(map, orig);
+        mergeInto(map, toMerge, false);
+        mergeInto(map, orig, true);
       }
       for (var value : map.values()) {
         handleMergeOperator(value);
@@ -68,12 +68,16 @@ private static void handleMergeOperator(Object parsed) {
   }
 
   @SuppressWarnings("rawtypes")
-  private static void mergeInto(Map dest, Object source) {
+  private static void mergeInto(Map dest, Object source, boolean replace) {
     if (source instanceof Map<?, ?> map) {
-      dest.putAll(map);
+      if (replace) {
+        dest.putAll(map);
+      } else {
+        map.forEach(dest::putIfAbsent);
+      }
     } else if (source instanceof List<?> nesteds) {
       for (var nested : nesteds) {
-        mergeInto(dest, nested);
+        mergeInto(dest, nested, replace);
       }
     }
   }
diff --git a/planetiler-core/src/test/java/com/onthegomap/planetiler/util/YamlTest.java b/planetiler-core/src/test/java/com/onthegomap/planetiler/util/YamlTest.java
index 67561f262b..f28eb20b00 100644
--- a/planetiler-core/src/test/java/com/onthegomap/planetiler/util/YamlTest.java
+++ b/planetiler-core/src/test/java/com/onthegomap/planetiler/util/YamlTest.java
@@ -123,7 +123,7 @@ void testMergeOperatorMultiple() {
         a: 2
         b: 3
       dest:
-        a: 2
+        a: 1 # from label1 since it came first
         b: 4
         c: 5
         z: 1
@@ -182,10 +182,11 @@ void testMergeOperatorFromDraft1() {
       - &BIG { r: 10 }
       - &SMALL { r: 1 }
       - # Merge one map
-	      << : *CENTER
-	      r: 10
-	      label: center/big
+       << : *CENTER
+       r: 10
+       label: center/big
       """);
+  }
 
   @Test
   void testMergeOperatorFromDraft2() {