fix: add warning for unsupported keepAcl param in file#copy

src/file.ts

@@ -295,6 +295,7 @@ export interface FileOptions {
 
 export interface CopyOptions {
   destinationKmsKeyName?: string;
+  keepAcl?: string;
   predefinedAcl?: string;
   token?: string;
   userProject?: string;
@@ -858,6 +859,8 @@ class File extends ServiceObject<File> {
    *     `projects/my-project/locations/location/keyRings/my-kr/cryptoKeys/my-key`,
    *     that will be used to encrypt the object. Overwrites the object
    * metadata's `kms_key_name` value, if any.
+   * @property {string} [keepAcl] This parameter is not supported and will be
+   *     removed in the next major.
    * @property {string} [predefinedAcl] Set the ACL for the new file.
    * @property {string} [token] A previously-returned `rewriteToken` from an
    *     unfinished rewrite request.
@@ -984,6 +987,13 @@ class File extends ServiceObject<File> {
       options = optionsOrCallback;
     }
 
+    if (options.hasOwnProperty('keepAcl')) {
+      // TODO: remove keepAcl from interface in next major.
+      console.warn(
+        'keepAcl parameter is not supported and will be removed in the next major'
+      );
+    }
+
     options = extend(true, {}, options);
     callback = callback || util.noop;
 

test/file.ts

@@ -345,6 +345,18 @@ describe('File', () => {
   });
 
   describe('copy', () => {
+    it('should warn if `keepAcl` parameter is passed', () => {
+      const consoleStub = sinon.stub(console, 'warn');
+      file.request = util.noop;
+      file.copy('newFile', {keepAcl: 'private'}, assert.ifError);
+      assert.ok(
+        consoleStub.calledWith(
+          'keepAcl parameter is not supported and will be removed in the next major'
+        )
+      );
+      sinon.restore();
+    });
+
     it('should throw if no destination is provided', () => {
       assert.throws(() => {
         file.copy();