Setting unprintable metadata is not consistent with Amazon S3.

[ichi-shin]

If some metadata contains unprintable characters, the "x-amz-missing-meta" header should be returned with a value of the number of the unprintable metadata entries.

But in the same case, swift3 behaves differently.

#Amazon S3
- PUT Object
$ ./s3curl.pl --id aws1 -- -s https://s3.amazonaws.com/header-missing/obj -X PUT -T testFile -H 'x-amz-meta-(): foo'| xmlindent
- HEAD Object
$ ./s3curl.pl --id aws1 -- -s -v -I https://s3.amazonaws.com/header-missing/obj -X HEAD| xmlindent

HTTP/1.1 200 OK
x-amz-id-2: ryetA05B/Ejh0O/hNG9TrYCS+GqPeZP79LeK6yNx7q4CL7kwxME9x/dxvmte3fVe
x-amz-request-id: 7A8FD61EE5308256
Date: Tue, 09 Dec 2014 06:09:33 GMT
x-amz-missing-meta: 1
Last-Modified: Tue, 09 Dec 2014 06:09:30 GMT
ETag: "7c12772809c1c0c3deda6103b10fdfa0"
Accept-Ranges: bytes
Content-Type: binary/octet-stream
Content-Length: 11
Server: AmazonS3

#swift3
- PUT Object
$ ./s3curl.pl --id test1 -- -s http://10.100.46.88/bucket/obj -X PUT -T NOTICE.txt -H 'x-amz-meta-(): foo'| xmlindent
- HEAD Object
$ ./s3curl.pl --id test1 -- -s -v -I http://10.100.46.88/bucket/obj -X HEAD| xmlindent

HTTP/1.1 200 OK
Content-Length: 117
x-amz-id-2: txc5343ab8e8044944912d1-0054869294
Last-Modified: Tue, 09 Dec 2014 06:10:49 GMT
ETag: "1b6006ff80bc24176a44ddb23da0b781"
x-amz-meta-(): foo
x-amz-request-id: txc5343ab8e8044944912d1-0054869294
Content-Type: application/octet-stream
X-Trans-Id: txc5343ab8e8044944912d1-0054869294
Date: Tue, 09 Dec 2014 06:11:32 GMT

[Kota Tsuyuzaki (tsuyuzaki-kota)]

That's sounds right.

However, I wonder how it affects for swift3 users.

In addition, I wonder if you could tell me how can we make sure what charactors belong to the unprintable character of S3.

Have you already have any idea?