fix incremental pulls in get_bucket to not assume exact field order (related to #414)

Author: s-u

R/get_bucket.R

@@ -56,9 +56,13 @@ get_bucket <- function(bucket,
                 marker = if (!is.null(r[["NextMarker"]])) r[["NextMarker"]] else tail(r[names(r) == "Contents"], 1)[["Contents"]][["Key"]]
             )
             extra <- s3HTTP(verb = "GET", bucket = bucket, query = query, parse_response = parse_response, ...)
-            new_r <- c(r, tail(extra, -5))
+            ## append only the "Contents" entries
+            new_r <- c(r, extra[names(extra) == "Contents"])
+            ## update specific entries in the result from the next batch
             new_r[["MaxKeys"]] <- as.character(as.integer(r[["MaxKeys"]]) + as.integer(extra[["MaxKeys"]]))
             new_r[["IsTruncated"]] <- extra[["IsTruncated"]]
+            new_r[["Marker"]] <- NULL ## remove any existing markers
+            new_r[["NextMarker"]] <- extra[["NextMarker"]] ## can be NULL which is fine
             attr(new_r, "x-amz-id-2") <- attr(r, "x-amz-id-2")
             attr(new_r, "x-amz-request-id") <- attr(r, "x-amz-request-id")
             attr(new_r, "date") <- attr(r, "date")