From 8e23b1b1df60d81ae58a93998228a8a60a72cc93 Mon Sep 17 00:00:00 2001
From: George Fu <kuhe@users.noreply.github.com>
Date: Fri, 8 Sep 2023 15:19:53 -0400
Subject: [PATCH] fix: allow lowercase endpoint param (#923)

---
 .../endpointsV2/ParameterGenerator.java        | 18 ++++++++++++++++--
 .../endpointsV2/RuleSetParametersVisitor.java  |  2 +-
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/endpointsV2/ParameterGenerator.java b/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/endpointsV2/ParameterGenerator.java
index 3bb10554e00..88cf56867ff 100644
--- a/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/endpointsV2/ParameterGenerator.java
+++ b/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/endpointsV2/ParameterGenerator.java
@@ -30,11 +30,21 @@ public class ParameterGenerator {
     private final String parameterName;
     private final Node param;
     private boolean required = false;
+    private boolean isInputKey;
     private String tsParamType = "string";
 
-    public ParameterGenerator(String key, Node param) {
+    /**
+     * @param key - the param name.
+     * @param param - the param value.
+     * @param isInputKey - whether the key is a client input key. This is
+     *                     distinct from canonical endpoint param name
+     *                     because it has been transformed to match
+     *                     pre-existing keys in published clients.
+     */
+    public ParameterGenerator(String key, Node param, boolean isInputKey) {
         parameterName = key;
         this.param = param;
+        this.isInputKey = isInputKey;
 
         ObjectNode paramNode = param.asObjectNode()
             .orElseThrow(() -> new RuntimeException("param node is not object node."));
@@ -60,6 +70,10 @@ public ParameterGenerator(String key, Node param) {
         }
     }
 
+    public ParameterGenerator(String key, Node param) {
+        this(key, param, false);
+    }
+
     public boolean isBuiltIn() {
         return param.expectObjectNode().containsMember("builtIn");
     }
@@ -114,7 +128,7 @@ public String toCodeString(boolean isClientContextParam) {
         }
         buffer += ": ";
 
-        if (parameterName.equals("endpoint")) {
+        if (parameterName.equals("endpoint") && isInputKey) {
             buffer += "string | Provider<string> | Endpoint | Provider<Endpoint> | EndpointV2 | Provider<EndpointV2>;";
         } else {
             if (isClientContextParam) {
diff --git a/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/endpointsV2/RuleSetParametersVisitor.java b/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/endpointsV2/RuleSetParametersVisitor.java
index 67fdc2ae470..f3bef984b67 100644
--- a/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/endpointsV2/RuleSetParametersVisitor.java
+++ b/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/endpointsV2/RuleSetParametersVisitor.java
@@ -63,7 +63,7 @@ public Void objectNode(ObjectNode node) {
                 localKey = EndpointsParamNameMap.getLocalName(key);
             }
 
-            ParameterGenerator parameterGenerator = new ParameterGenerator(localKey, param);
+            ParameterGenerator parameterGenerator = new ParameterGenerator(localKey, param, useLocalNames);
 
             if (localKey.equals("endpoint")) {
                 writer.addImport("Endpoint", null, TypeScriptDependency.SMITHY_TYPES);