ARSN-392 Fix processVersionSpecificPut

- For backward compatibility (if isNull is undefined), add the nullVersionId field to the master update. The nullVersionId is needed for listing, retrieving, and deleting null versions.

- For the new null key implementation (if isNull is defined): add the isNull2 field and set it to true to specify that the new version is null AND has been put with a Cloudserver handling null keys (i.e., supporting S3C-7352).

- Manage scenarios in which a version is marked with the isNull attribute set to true, but without a version ID. This happens after BackbeatClient.putMetadata() is applied to a standalone null master.

lib/versioning/Version.ts

@@ -3,7 +3,7 @@ import { VersioningConstants } from './constants';
 const VID_SEP = VersioningConstants.VersionId.Separator;
 /**
  * Class for manipulating an object version.
- * The format of a version: { isNull, isDeleteMarker, versionId, otherInfo }
+ * The format of a version: { isNull, isNull2, isDeleteMarker, versionId, otherInfo }
  *
  * @note Some of these functions are optimized based on string search
  * prior to a full JSON parse/stringify. (Vinh: 18K op/s are achieved
@@ -13,6 +13,7 @@ const VID_SEP = VersioningConstants.VersionId.Separator;
 export class Version {
     version: {
         isNull?: boolean;
+        isNull2?: boolean;
         isDeleteMarker?: boolean;
         versionId?: string;
         isPHD?: boolean;
@@ -22,12 +23,16 @@ export class Version {
      * Create a new version instantiation from its data object.
      * @param version - the data object to instantiate
      * @param version.isNull - is a null version
+     * @param version.isNull2 - Whether new version is null or not AND has
+     * been put with a Cloudserver handling null keys (i.e. supporting
+     * S3C-7352)
      * @param version.isDeleteMarker - is a delete marker
      * @param version.versionId - the version id
      * @constructor
      */
     constructor(version?: {
         isNull?: boolean;
+        isNull2?: boolean;
         isDeleteMarker?: boolean;
         versionId?: string;
         isPHD?: boolean;
@@ -83,6 +88,31 @@ export class Version {
         return `{ "isPHD": true, "versionId": "${versionId}" }`;
     }
 
+    /**
+     * Appends a key-value pair to a JSON object represented as a string. It adds
+     * a comma if the object is not empty (i.e., not just '{}'). It assumes the input
+     * string is formatted as a JSON object.
+     *
+     * @param {string} stringifiedObject The JSON object as a string to which the key-value pair will be appended.
+     * @param {string} key The key to append to the JSON object.
+     * @param {string} value The value associated with the key to append to the JSON object.
+     * @returns {string} The updated JSON object as a string with the new key-value pair appended.
+     * @example
+     * _jsonAppend('{"existingKey":"existingValue"}', 'newKey', 'newValue');
+     * // returns '{"existingKey":"existingValue","newKey":"newValue"}'
+     */
+    static _jsonAppend(stringifiedObject: string, key: string, value: string): string {
+        // stringifiedObject value has the format of '{...}'
+        let index = stringifiedObject.length - 2;
+        while (stringifiedObject.charAt(index--) === ' ');
+        const comma = stringifiedObject.charAt(index + 1) !== '{';
+        return (
+            `${stringifiedObject.slice(0, stringifiedObject.length - 1)}` + // eslint-disable-line
+            (comma ? ',' : '') +
+            `"${key}":"${value}"}`
+        );
+    }
+
     /**
      * Put versionId into an object in the (cheap) way of string manipulation,
      * instead of the more expensive alternative parsing and stringification.
@@ -93,14 +123,32 @@ export class Version {
      */
     static appendVersionId(value: string, versionId: string): string {
         // assuming value has the format of '{...}'
-        let index = value.length - 2;
-        while (value.charAt(index--) === ' ');
-        const comma = value.charAt(index + 1) !== '{';
-        return (
-            `${value.slice(0, value.length - 1)}` + // eslint-disable-line
-            (comma ? ',' : '') +
-            `"versionId":"${versionId}"}`
-        );
+        return Version._jsonAppend(value, 'versionId', versionId);
+    }
+
+    /**
+    * Updates or appends a `nullVersionId` property to a JSON-formatted string.
+    * This function first checks if the `nullVersionId` property already exists within the input string.
+    * If it exists, the function updates the `nullVersionId` with the new value provided.
+    * If it does not exist, the function appends a `nullVersionId` property with the provided value.
+    *
+    * @static
+    * @param {string} value - The JSON-formatted string that may already contain a `nullVersionId` property.
+    * @param {string} nullVersionId - The new value for the `nullVersionId` property to be updated or appended.
+    * @returns {string} The updated JSON-formatted string with the new `nullVersionId` value.
+    */
+    static updateOrAppendNullVersionId(value: string, nullVersionId: string): string {
+        // Check if "nullVersionId" already exists in the string
+        const nullVersionIdPattern = /"nullVersionId":"[^"]*"/;
+        const nullVersionIdExists = nullVersionIdPattern.test(value);
+
+        if (nullVersionIdExists) {
+            // Replace the existing nullVersionId with the new one
+            return value.replace(nullVersionIdPattern, `"nullVersionId":"${nullVersionId}"`);
+        } else {
+            // Append nullVersionId
+            return Version._jsonAppend(value, 'nullVersionId', nullVersionId);
+        }
     }
 
     /**
@@ -190,6 +238,16 @@ export class Version {
         return this;
     }
 
+    /**
+     * Mark that the null version has been put with a Cloudserver handling null keys (i.e. supporting S3C-7352)
+     * 
+     * @return - the updated version
+     */
+    setNull2Version() {
+        this.version.isNull2 = true;
+        return this;
+    }
+
     /**
      * Serialize the version.
      *

lib/versioning/VersioningRequestProcessor.ts

@@ -496,6 +496,7 @@ export default class VersioningRequestProcessor {
                 const versionIdFromMaster = masterVersion.getVersionId();
                 if (versionIdFromMaster === undefined ||
                     versionIdFromMaster >= versionId) {
+                    let value = request.value;
                     logger.debug('version to put is not older than master');
                     // new behavior when isNull is defined is to only
                     // update the master key if it is the latest
@@ -509,7 +510,7 @@ export default class VersioningRequestProcessor {
                         request.options.isNull === undefined) {
                         // master key is strictly older than the put version
                         let masterVersionId;
-                        if (masterVersion.isNullVersion()) {
+                        if (masterVersion.isNullVersion() && versionIdFromMaster) {
                             logger.debug('master key is a null version');
                             masterVersionId = versionIdFromMaster;
                         } else if (versionIdFromMaster === undefined) {
@@ -537,13 +538,22 @@ export default class VersioningRequestProcessor {
                                   '' : masterVersionId;
                             const masterVersionKey = formatVersionKey(key, masterKeyVersionId);
                             masterVersion.setNullVersion();
+                            // isNull === false means Cloudserver supports null keys,
+                            // so create a null key with the isNull2 flag
+                            if (request.options.isNull === false) {
+                                masterVersion.setNull2Version();
+                            // else isNull === undefined means Cloudserver does not support null keys,
+                            // hence set/update the new master nullVersionId for backward compatibility
+                            } else {
+                                value = Version.updateOrAppendNullVersionId(request.value, masterVersionId);
+                            }
                             ops.push({ key: masterVersionKey,
                                        value: masterVersion.toString() });
                         }
                     } else {
                         logger.debug('version to put is the master');
                     }
-                    ops.push({ key, value: request.value });
+                    ops.push({ key, value: value });
                 } else {
                     logger.debug('version to put is older than master');
                     if (request.options.isNull === true && !masterVersion.isNullVersion()) {

tests/unit/versioning/Version.spec.js

@@ -0,0 +1,55 @@
+const { Version } = require('../../../lib/versioning/Version');
+
+describe('Version', () => {
+    describe('appendVersionId', () => {
+        it('should append versionId to an empty object', () => {
+            const emptyObject = '{}';
+            const versionId = '123';
+            const expected = '{"versionId":"123"}';
+            const result = Version.appendVersionId(emptyObject, versionId);
+            expect(result).toEqual(expected);
+        });
+
+        it('should append versionId to an object with existing properties', () => {
+            const existingObject = '{"key":"value"}';
+            const versionId = '456';
+            const expected = '{"key":"value","versionId":"456"}';
+            const result = Version.appendVersionId(existingObject, versionId);
+            expect(result).toEqual(expected);
+        });
+
+        it('should append versionId to an object with existing versionId', () => {
+            const objectWithVersionId = '{"key":"value","versionId":"old"}';
+            const versionId = 'new';
+            const expected = '{"key":"value","versionId":"old","versionId":"new"}';
+            const result = Version.appendVersionId(objectWithVersionId, versionId);
+            expect(result).toEqual(expected);
+        });
+    });
+
+    describe('updateOrAppendNullVersionId', () => {
+        it('should append nullVersionId when it does not exist', () => {
+            const initialValue = '{"key":"value"}';
+            const nullVersionId = '12345';
+            const expectedValue = '{"key":"value","nullVersionId":"12345"}';
+            const result = Version.updateOrAppendNullVersionId(initialValue, nullVersionId);
+            expect(result).toEqual(expectedValue);
+        });
+
+        it('should update nullVersionId when it exists', () => {
+            const initialValue = '{"key":"value","nullVersionId":"initial"}';
+            const nullVersionId = 'updated12345';
+            const expectedValue = '{"key":"value","nullVersionId":"updated12345"}';
+            const result = Version.updateOrAppendNullVersionId(initialValue, nullVersionId);
+            expect(result).toEqual(expectedValue);
+        });
+
+        it('should handle empty string by appending nullVersionId', () => {
+            const initialValue = '{}';
+            const nullVersionId = 'emptyCase12345';
+            const expectedValue = '{"nullVersionId":"emptyCase12345"}';
+            const result = Version.updateOrAppendNullVersionId(initialValue, nullVersionId);
+            expect(result).toEqual(expectedValue);
+        });
+    });
+});