delimiter.js maxKeys==0 param issue

[jonathan-gramain]

In algos/list/delimiter.js, in the constructor of Delimiter class, if maxKeys is provided with a value of 0, it gets assigned to 1000 (this.maxKeys = parameters.maxKeys || 1000).

This causes the s3tests.functional.test_s3.test_bucket_list_maxkeys_zero CEPH test to fail because it expects zero entry when setting the limit to 0 but it has all of them.

@DavidPineauScality maybe this bug also affects MetaData in some way, although the ironman machine is obviously happy here, please check.

[jonathan-gramain]

0 seems to be considered as a special value in the current code, so it may not be easily fixable.

in delimiter.js:

    /**
     * check if the max keys count has been reached and set the
     * final state of the result if it is the case
     * @return {Boolean} - indicates if the iteration has to stop
     */
    _reachedMaxKeys() {
        if (this.keys >= this.maxKeys) {
            // In cases of maxKeys <= 0 -> IsTruncated = false
            this.IsTruncated = this.maxKeys > 0;
            return true;
        }
        return false;
    }

Assigning myself to keep track of it.

[jonathan-gramain]

Reading the above function, I also wonder if we don't return the wrong IsTruncated attribute when the total number of keys is exactly maxKeys.

Let's take a look at this issue from another angle:

• Is is even relevant to ask the backend to do a listing of 0 items ? This sounds like work for nothing.
• Should it not be handled by S3 itself instead, that could be directly answering with an empty listing ? (ie: Similarly as what we do for 0-byte objects)