resume of interrupted transfers from/to SMB shares not working as I had hoped

Does the latest curl library fully support resume of interrupted uploads to SMB shares?

By fully I mean avoiding copying the first part or seeking to EOF over the SMB connection.

If so should it also work for upload to SMB share as well as download?

To test it using curl 7.65.3 on MacOS Mohave I tried an interrupted download of ~ 2gb file from a windows share, which took approx. 35 seconds.

Then I deleted the file, started download again, interrupted with ctrl-c halfway through, and ran same command again, note it says it is resuming at byte xxxx.

The result was a file equal in size to the first part that made it when I interrupted plus the size of the whole file. It seems to have copied the whole file on the second try and appended to the first. In addition the total time of the second part copy is the same as copying the whole file and the progress shows same, even though the second one says it’s resuming at byte xxxx.

Seems like it’s trying to do the right thing but wondering if I should report as an issue, or maybe it has something to do with the version of SMB used on MacOS?

Alf (see test run below)

FIRST COPY OF WHOLE FILE – note size of file after copy (correct)

$ curl -O -C - -u username:password smb://172.16.166.133/repl/ubuntu-18.04.2-desktop-amd64.iso
  % Total % Received % Xferd Average Speed Time Time Time Current
                                 Dload Upload Total Spent Left Speed
100 1904M 100 1904M 0 0 52.3M 0 0:00:36 0:00:36 --:--:-- 53.4M

$ ls -al | grep ubuntu
-rw-r--r-- 1 alfred_eisenberg staff 1996488704 Jul 29 15:26 ubuntu-18.04.2-desktop-amd64.iso

$ rm ubuntu-18.04.2-desktop-amd64.iso

SECOND TIME – interrupted after 20 seconds and continued

$ curl -O -C - -u username:password smb://172.16.166.133/repl/ubuntu-18.04.2-desktop-amd64.iso
  % Total % Received % Xferd Average Speed Time Time Time Current
                                 Dload Upload Total Spent Left Speed
 57 1904M 57 1091M 0 0 52.2M 0 0:00:36 0:00:20 0:00:16 54.6M^C

$ ls -al | grep ubuntu
-rw-r--r-- 1 alfred_eisenberg staff 1165524992 Jul 29 15:28 ubuntu-18.04.2-desktop-amd64.iso

alfred_eisenberg_at_alfmbpr2:~/curlsmb$ curl -O -C - -u alfred_eisenberg:bordel smb://172.16.166.133/repl/ubuntu-18.04.2-desktop-amd64.iso
$ curl -O -C - -u alfred_eisenberg:bordel smb://172.16.166.133/repl/ubuntu-18.04.2-desktop-amd64.iso
** Resuming transfer from byte position 1165524992
  % Total % Received % Xferd Average Speed Time Time Time Current
                                 Dload Upload Total Spent Left Speed
100 1904M 100 1904M 0 0 52.7M 0 0:00:36 0:00:36 --:--:-- 54.2M
$ls -al | grep ubuntu
-rw-r--r-- 1 alfred_eisenberg staff 3162013696 Jul 29 15:29 ubuntu-18.04.2-desktop-amd64.iso



--
Alfred Eisenberg
[cid:image001.png_at_01D38A20.71838E70]
https://www.quest.com/

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