wip restore without nullVersionCompatMode md back

Author: BourgoisMickael

lib/services.js

@@ -175,6 +175,13 @@ const services = {
         }
         if (versionId || versionId === '') {
             options.versionId = versionId;
+            // Without nullVersionCompatMode (for metadata backend)
+            // a null version object key doesn't have versionId.
+            // Override md options.versionId to 'null' to avoid creating a new version object.
+            // At the end of processing to avoid impacting versionId in MD payload
+            if (headers &&headers['x-scal-s3-version-id'] === 'null' && !config.nullVersionCompatMode) {
+                options.versionId = 'null';
+            }
         }
         if (needOplogUpdate) {
             options.needOplogUpdate = true;

tests/functional/aws-node-sdk/test/utils/init.js

@@ -7,12 +7,19 @@ const log = new DummyRequestLogger();
 const nonVersionedObjId =
     versionIdUtils.getInfVid(config.replicationGroupId);
 
+const nullKeySupported = ['file', 'scality'].includes(config.backends.metadata);
+// With null version compat mode the null key should look like
+// 'object1putversion\u000099999999999999999999RG001  '
+// Without it for BucketFile backends it looks like
+// 'object1putversion\x00'
+const nullKey = nullKeySupported && !config.nullVersionCompatMode;
+
 function decodeVersionId(versionId) {
     let decodedVersionId;
     if (versionId) {
         if (versionId === 'null') {
             // At least file backend handles both
-            decodedVersionId = config.enableNullVersionCompatMode ? nonVersionedObjId : 'null';
+            decodedVersionId = nullKey ? 'null' : nonVersionedObjId;
         } else {
             decodedVersionId = versionIdUtils.decode(versionId);
         }