From 3cd697c85432bdefd21f91161906da9b046eef19 Mon Sep 17 00:00:00 2001
From: kstich <kevin@kstich.com>
Date: Fri, 8 Oct 2021 16:21:28 -0700
Subject: [PATCH] Maintain schema property order in JsonSchema

---
 .../java/software/amazon/smithy/jsonschema/Schema.java |  5 +++--
 .../software/amazon/smithy/jsonschema/SchemaTest.java  | 10 ++++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/smithy-jsonschema/src/main/java/software/amazon/smithy/jsonschema/Schema.java b/smithy-jsonschema/src/main/java/software/amazon/smithy/jsonschema/Schema.java
index 12e5fa67872..f7b970a4ce2 100644
--- a/smithy-jsonschema/src/main/java/software/amazon/smithy/jsonschema/Schema.java
+++ b/smithy-jsonschema/src/main/java/software/amazon/smithy/jsonschema/Schema.java
@@ -20,6 +20,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -575,10 +576,10 @@ public static final class Builder implements SmithyBuilder<Schema> {
         private Integer maxProperties;
         private Integer minProperties;
         private Collection<String> required = new ArrayList<>();
-        private Map<String, Schema> properties = new HashMap<>();
+        private Map<String, Schema> properties = new LinkedHashMap<>();
         private Schema additionalProperties;
         private Schema propertyNames;
-        private Map<String, Schema> patternProperties = new HashMap<>();
+        private Map<String, Schema> patternProperties = new LinkedHashMap<>();
 
         private List<Schema> allOf = ListUtils.of();
         private List<Schema> anyOf = ListUtils.of();
diff --git a/smithy-jsonschema/src/test/java/software/amazon/smithy/jsonschema/SchemaTest.java b/smithy-jsonschema/src/test/java/software/amazon/smithy/jsonschema/SchemaTest.java
index 451e78184f6..3c218f32256 100644
--- a/smithy-jsonschema/src/test/java/software/amazon/smithy/jsonschema/SchemaTest.java
+++ b/smithy-jsonschema/src/test/java/software/amazon/smithy/jsonschema/SchemaTest.java
@@ -183,6 +183,16 @@ public void ignoresNegativeNumericPositions() {
         assertThat(schema.selectSchema("allOf", "-1"), equalTo(Optional.empty()));
     }
 
+    @Test
+    public void maintainsPropertyOrder() {
+        Schema schema = Schema.builder()
+                .putProperty("foo", Schema.builder().build())
+                .putProperty("bar", Schema.builder().build())
+                .build();
+
+        assertThat(schema.getProperties().keySet(), contains("foo", "bar"));
+    }
+
     @Test
     public void removingPropertiesRemovesRequiredPropertiesToo() {
         Schema schema = Schema.builder()