Retry mechanism in prep-source-build.sh doesn't work?

[ViktorHofer]

Noticed these issues in two separate source-build jobs:

  Looking for source-built Artifacts to download...
  Downloading source-built Artifacts from https://builds.dotnet.microsoft.com/source-built-artifacts/assets/Private.SourceBuilt.Artifacts.10.0.100-preview.6.25302.104.centos.9-x64.tar.gz...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed

  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
 11  855M   11  100M    0     0   102M      0  0:00:08 --:--:--  0:00:08  101M
 15  855M   15  131M    0     0  66.0M      0  0:00:12  0:00:01  0:00:11 66.0M
 21  855M   21  182M    0     0  60.6M      0  0:00:14  0:00:03  0:00:11 60.6M
 23  855M   23  202M    0     0  59.3M      0  0:00:14  0:00:03  0:00:11 59.3M
curl: (18) transfer closed with 685575526 bytes remaining to read

https://dev.azure.com/dnceng/internal/_build/results?buildId=2727614&view=logs&j=1fe64c67-15ac-5f21-8981-01e907d8d7cf&t=a18a4674-ae83-5f07-01f2-23b99b2862bd

This line tells me that curl already receives the retry parameter: https://github.com/dotnet/dotnet/blob/f42e60ee0e8facdc764f81a78c34a89b56e3c14c/prep-source-build.sh#L177

But it clearly doesn't retry when the transfer gets closed.

[ViktorHofer]

Ok so curl 18 is CURLE_PARTIAL_FILE and doesn't count as a retry condition: https://curl.se/docs/manpage.html

According to others this is most likely a server issue.