Differences between `rc` and `mc` for the `anonymous set` command

[NikTerentev]

Our team used a workflow similar to this for MinIO mc:

mc alias set local http://localhost:9001 root rootroot
mc mb local/my-bucket
mc anonymous set public "local/my-bucket/persons/music/**"
mc anonymous set public "local/my-bucket/profiles/images/**"
mc anonymous get-json local/my-bucket

Result json policy:

{
 "Statement": [
  {
   "Action": [
    "s3:GetBucketLocation",
    "s3:ListBucketMultipartUploads"
   ],
   "Effect": "Allow",
   "Principal": {
    "AWS": [
     "*"
    ]
   },
   "Resource": [
    "arn:aws:s3:::my-bucket"
   ]
  },
  {
   "Action": [
    "s3:ListBucket"
   ],
   "Condition": {
    "StringEquals": {
     "s3:prefix": [
      "persons/music/**",
      "profiles/images/**"
     ]
    }
   },
   "Effect": "Allow",
   "Principal": {
    "AWS": [
     "*"
    ]
   },
   "Resource": [
    "arn:aws:s3:::my-bucket"
   ]
  },
  {
   "Action": [
    "s3:AbortMultipartUpload",
    "s3:DeleteObject",
    "s3:GetObject",
    "s3:ListMultipartUploadParts",
    "s3:PutObject"
   ],
   "Effect": "Allow",
   "Principal": {
    "AWS": [
     "*"
    ]
   },
   "Resource": [
    "arn:aws:s3:::my-bucket/persons/music/***",
    "arn:aws:s3:::my-bucket/profiles/images/***"
   ]
  }
 ],
 "Version": "2012-10-17"
}

After MinIO free Docker images deletion, we decided to switch to RustFS using rc:

rc alias set local http://localhost:9000 root rootroot
rc mb local/my-bucket
rc anonymous set public "local/my-bucket/persons/music"
rc anonymous set public "local/my-bucket/profiles/images"
rc anonymous get-json local/my-bucket

And we get this json policy:

{
  "Statement": [
    {
      "Action": [
        "s3:GetObject"
      ],
      "Effect": "Allow",
      "Principal": "*",
      "Resource": "arn:aws:s3:::my-bucket/profiles/images/*",
      "Sid": "AnonymousRead1"
    },
    {
      "Action": "s3:ListBucket",
      "Condition": {
        "StringLike": {
          "s3:prefix": [
            "profiles/images",
            "profiles/images/*",
            "profiles/images*"
          ]
        }
      },
      "Effect": "Allow",
      "Principal": "*",
      "Resource": "arn:aws:s3:::my-bucket",
      "Sid": "AnonymousList2"
    },
    {
      "Action": [
        "s3:PutObject"
      ],
      "Effect": "Allow",
      "Principal": "*",
      "Resource": "arn:aws:s3:::my-bucket/profiles/images/*",
      "Sid": "AnonymousWrite3"
    }
  ],
  "Version": "2012-10-17"
}

(Public access to persons/music has been lost)

This slightly disrupted our transition from mc to rc; we had to add a json file and use anonymous set-json command instead.

Is it possible to update the rc so that it extends the existing policy for the bucket rather than overwriting it completely? I noticed there’s a warning message about this when using the cli (Warning: setting 'local/my-bucket/profiles/images' will replace the entire bucket policy for 'my-bucket', which may remove unrelated statements). Is this restriction really necessary?