No way to update metadata in copyObject

Hello,

I am trying to use copyObject to copy a file over itself while updating lastModified on it. However, this fails with this error:

S3Error: This copy request is illegal because it is trying to copy an object to itself without changing the object's metadata, storage class, website redirect location or encryption attributes.

I’ve noticed that some of the other client libraries do include metadata fields in their copyObject - however I can also see how adding a parameter would introduce a potentially breaking change.

I can work with either of these two solutions:

• Update lastModified when copying an object onto itself
• Adding a parameter for new metadata
• Adding an overflow method that replaces the conditions parameter with an object (an example):

const conds = new Minio.CopyConditions();
const options = {
    conditions: conds,
    metadata: {
        lastModified: new Date()
    }
}
client.copyObject('bucket', 'prefix/file', '/bucket/prefix/file', options, callback);

For now I will have to stick with the download/reupload workaround - but using copyObject will be far more efficient.

Thank you!

[Chhunneng]

The code below is Python.

result = client.stat_object("bucket", "object.txt")
current_metadata = {}
for key in result.metadata:
    if "X-Amz-Meta" in key:
        current_metadata[key.split("-")[-1]] = result.metadata[key]
client.copy_object(
    "bucket",
    "object.txt",
    CopySource("bucket", "object.txt"),
    metadata={**current_metadata, "Age": "121212",
              "Owner": "me", "money": "1M $"},
    metadata_directive=REPLACE
)
result = client.stat_object("bucket", "object.txt")

Now I am using this method to update metadata. I hope we will have the function to update metadata directly.

[balamurugana]

Why is this issue relevant to current minio-py?