s3api claims to delete an object when it hasn't actually done it

One more argument in favor of issuing the delete: container listings may never have gotten the message about object deletes. This may lead to containers you can't easily delete via the S3 API (if, say, your s3 client is opinionated and only wants to issue multi-deletes). May be the root cause for https://ask.openstack.org/en/question/114715/s3-method-post-on-bucket-with-query-delete-doesnt-work/

Tim, with reference to the ask.openstack query, the MultiPart object never received the delete, hence the container was not updated.

root@VM:~# s3cmd del --recursive --force --region us-east-1 s3://bucket9
delete: 's3://bucket9/2M_file.file'
delete: 's3://bucket9/firmimg.d7'
root@VM:~# s3cmd ls --region us-east-1 s3://bucket9
2019-01-03 08:21 105639142 s3://bucket9/firmimg.d7

Proxy-server logs:
root@VM:~# grep bucket9 /var/log/swift/proxy.log
Jan 4 05:43:40.891106 hostname proxy-server: {'access_key': 'xxxxxxxxxxxxxxxxxxxxxxxf1717b67f', 'container_name': 'bucket9', '_timestamp': 1546580620.00000_0000000000000000, 'user_id': None, 'slo_enabled': True, '_signed_headers': set(['x-amz-content-sha256', 'host', 'x-amz-date']), 'string_to_sign': 'AWS4-HMAC-SHA256\n20190104T054340Z\n20190104/us-east-1/s3/aws4_request\n324616a0858b1da3e27453fa34401678f3c58e131dfbff23b99678bd493c3d0d', '_params_cache': {}, 'headers': <swift.common.swob.HeaderEnvironProxy object at 0x7f4e3fc97d50>, 'object_name': '', 'bucket_in_host': None, 'environ': {'HTTP_AUTHORIZATION': 'AWS xxxxxxxxxxxxxxxxxxxxxxxf1717b67f:c83ebdfe2e77e1a2c199611359e89a5309196b29c987ddd13dfe046f83339fa1', 'SCRIPT_NAME': '', 'keystone.token_auth': <keystonemiddleware.auth_token._user_plugin.UserAuthPlugin object at 0x7f4e3fb585d0>, 'webob.adhoc_attrs': {'response': <_AuthTokenResponse at 0x7f4e3fafcf50 200 OK>}, 'REQUEST_METHOD': 'GET', 'HTTP_X_AMZ_DATE': '20190104T054340Z', 'PATH_INFO': '/bucket9/', 'SERVER_PROTOCOL': 'HTTP/1.0', 'REMOTE_ADDR': '150.50.2.135', 'CONTENT_LENGTH': '0', 'eventlet.posthooks': [], 'RAW_PATH_INFO': '/bucket9/', 'REMOTE_PORT': '49285', 'eventlet.input': <eventlet.wsgi.Input object at 0x7f4e3fc53fd0>, 'HTTP_X_IDENTITY_STATUS': 'Invalid', 'wsgi.url_scheme': 'http', 'SERVER_PORT': '80', 'HTTP_X_AMZ_CONTENT_SHA256': 'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855', 'swift.leave_relative_location': True, 'wsgi.input': <eventlet.wsgi.Input object at 0x7f4e3fc53fd0>, 'HTTP_HOST': 'vsa-00000ae2-zadara-dev2.zadarazios.com', 'swift.cache': <swift.common.memcached.MemcacheRing object at 0x7f4e3fc6bf10>, 'wsgi.multithread': True, 'wsgi.version': (1, 0), 'SERVER_NAME': '150.50.2.135', 'GATEWAY_INTERFACE': 'CGI/1.1', 'wsgi.run_once': False, 'wsgi.errors': <swift.common.utils.LoggerFileObject object at 0x7f4e3fbf9fd0>, 'wsgi.multiprocess': False, 'swift.trans_id': 'tx79aefa29e485496fa408b-005c2ef28c', 'CONTENT_TYPE': None, 'swift3.auth_details': {'access_key': 'xxxxxxxxxxxxxxxxxxxxxxxf1717b67f', 'check_signature': <bound method SigV4Request.check_signature of <swift3.request.SigV4Request object at 0x7f4e3fc97090>>, 'string_to_sign': 'AWS4-HMAC-SHA256\n20190104T054340Z\n20190104/us-east-1/s3/aws4_request\n324616a0858b1da3e27453fa34401678f3c58e131dfbff23b99678bd493c3d0d', 'signature': 'c83ebdfe2e77e1a2c199611359e89a5309196b29c987ddd13dfe046f83339fa1'}, 'HTTP_ACCEPT_ENCODING': 'identity'}, 'token': None, 'signature': 'c83ebdfe2e77e1a2c199611359e89a5309196b29c987ddd13dfe046f83339fa1', 'account': None}
Jan 4 05:43:41.105368 hostname proxy-server: - - 04/Jan/2019/05/43/41 HEAD /v1/AUTH_e99dfde4680f4b2f8a270f66ab3d2cf1/bucket9 HTTP/1.0 204 - Swift - - - - tx79ae...

Thanks for the extra info Bhaskar! I wrote up https://bugs.launchpad.net/swift/+bug/1810567 to describe your trouble, and https://review.openstack.org/#/c/628701/ to fix it.

Thanks a lot, Tim!