Fixed the issue where slash from path parameter got removed with endp… (#3964)

* Fixed the issue where slash from path parameter got removed with endpoint override that contains a trailing slash

* Not strip slash

Author: zoewangg

codegen/src/main/resources/software/amazon/awssdk/codegen/rules/AwsEndpointProviderUtils.java.resource

@@ -150,19 +150,33 @@ public final class AwsEndpointProviderUtils {
         String clientEndpointPath = clientEndpoint.getRawPath();
 
         // [client endpoint path]/[request path]
-        String requestPath = request.getUri().getRawPath();
+        String requestPath = request.encodedPath();
 
         // [client endpoint path]/[additional path added by resolver]
         String resolvedUriPath = resolvedUri.getRawPath();
 
-        // our goal is to construct [client endpoint path]/[additional path added by resolver]/[request path], so we
-        // just need to strip the client endpoint path from the marshalled request path to isolate just the part added
-        // by the marshaller
-        String requestPathWithClientPathRemoved = StringUtils.replaceOnce(requestPath, clientEndpointPath, "");
-        String finalPath = SdkHttpUtils.appendUri(resolvedUriPath, requestPathWithClientPathRemoved);
+        String finalPath = requestPath;
+
+        // If there is an additional path added by resolver, i.e., [additional path added by resolver] not null,
+        // we need to combine the path
+        if (!resolvedUriPath.equals(clientEndpointPath)) {
+            finalPath = combinePath(clientEndpointPath, requestPath, resolvedUriPath);
+        }
 
         return request.toBuilder().protocol(resolvedUri.getScheme()).host(resolvedUri.getHost()).port(resolvedUri.getPort())
-                .encodedPath(finalPath).build();
+                      .encodedPath(finalPath).build();
+    }
+
+    /**
+     * Our goal is to construct [client endpoint path]/[additional path added by resolver]/[request path], so we just need to
+     * strip the client endpoint path from the marshalled request path to isolate just the part added by the marshaller. Trailing
+     * slash is removed from client endpoint path before stripping because it could cause the leading slash to be removed from the
+     * request path: e.g., StringUtils.replaceOnce("/", "//test", "") generates "/test" and the expected result is "//test"
+     */
+    private static String combinePath(String clientEndpointPath, String requestPath, String resolvedUriPath) {
+        String requestPathWithClientPathRemoved = StringUtils.replaceOnce(requestPath, clientEndpointPath, "");
+        String finalPath = SdkHttpUtils.appendUri(resolvedUriPath, requestPathWithClientPathRemoved);
+        return finalPath;
     }
 
     public static AwsRequest addHeaders(AwsRequest request, Map<String, List<String>> headers) {

core/sdk-core/src/main/java/software/amazon/awssdk/core/interceptor/SdkExecutionAttribute.java

@@ -67,7 +67,8 @@ public class SdkExecutionAttribute {
     public static final ExecutionAttribute<Boolean> ENDPOINT_OVERRIDDEN = new ExecutionAttribute<>("EndpointOverridden");
 
     /**
-     * This is the endpointOverride (if {@link #ENDPOINT_OVERRIDDEN} is true), otherwise null.
+     * This is the endpointOverride (if {@link #ENDPOINT_OVERRIDDEN} is true), otherwise the endpoint generated from regional
+     * metadata.
      */
     public static final ExecutionAttribute<URI> CLIENT_ENDPOINT = new ExecutionAttribute<>("EndpointOverride");
 

test/codegen-generated-classes-test/src/test/java/software/amazon/awssdk/services/endpointproviders/AwsEndpointProviderUtilsTest.java

@@ -250,6 +250,35 @@ public void setUri_combinesPathsCorrectly() {
             .isEqualTo("https://override.example.com/a/b/c");
     }
 
+    @Test
+    public void setUri_doubleSlash_combinesPathsCorrectly() {
+        URI clientEndpoint = URI.create("https://override.example.com/a");
+        URI requestUri = URI.create("https://override.example.com/a//c");
+        URI resolvedUri = URI.create("https://override.example.com/a/b");
+
+        SdkHttpRequest request = SdkHttpRequest.builder()
+                                               .uri(requestUri)
+                                               .method(SdkHttpMethod.GET)
+                                               .build();
+
+        assertThat(AwsEndpointProviderUtils.setUri(request, clientEndpoint, resolvedUri).getUri().toString())
+            .isEqualTo("https://override.example.com/a/b//c");
+    }
+
+    @Test
+    public void setUri_withTrailingSlashNoPath_combinesPathsCorrectly() {
+        URI clientEndpoint = URI.create("https://override.example.com/");
+        URI requestUri = URI.create("https://override.example.com//a");
+        URI resolvedUri = URI.create("https://override.example.com/");
+        SdkHttpRequest request = SdkHttpRequest.builder()
+                                               .uri(requestUri)
+                                               .method(SdkHttpMethod.GET)
+                                               .build();
+
+        assertThat(AwsEndpointProviderUtils.setUri(request, clientEndpoint, resolvedUri).getUri().toString())
+            .isEqualTo("https://override.example.com//a");
+    }
+
     @Test
     public void setHeaders_existingValuesOnOverride_combinesWithNewValues() {
         AwsRequest request = AllTypesRequest.builder()