retry on failure to avoid frequent 443 / 503 / etc github/download errors

[timotheecour]

either nimble should retry on failure, on nim CI should retry on failure to avoid frequent flaky test failures caused by spurious 443 / 503 / etc github/download errors.

Example

see some examples here: timotheecour#266

Current Output

• Error: unhandled exception: Unable to query remote tags for
• Failure: reInstallFailed
• error: RPC failed

for example in #16242
https://dev.azure.com/nim-lang/Nim/_build/results?buildId=10637&view=logs&jobId=30931762-47c4-53b3-6a83-316eb5a6b9d7&j=ba7bbfa4-f55c-5c34-6d52-1b6b4edd3f37&t=d3579a4b-a806-5abe-ed48-07e8693a62db

Downloading https://github.com/Araq/libffi using git
       Tip: 3 messages have been suppressed, use --verbose to show them.
     Error: Execution failed with exit code 128
        ... Command: git clone --recursive --depth 1 -b 1.0.4 https://github.com/Araq/libffi /tmp/nimble_87545/githubcom_Araqlibffi
        ... Output: Cloning into '/tmp/nimble_87545/githubcom_Araqlibffi'...
        ... error: RPC failed; curl 18 transfer closed with outstanding read data remaining
        ... fatal: expected flush after ref listing

Failure: reInstallFailed
  git clone loloicci/nimly pkgstemp/nimly
  Cloning into 'pkgstemp/nimly'...
  error: RPC failed; curl 18 transfer closed with outstanding read data remaining
  fatal: error reading section header 'shallow-info'

Expected Output

works

Possible Solution

I had largely eliminated this problem in #14547 with actionRetry (with exponential backoff) but actionRetry was reverted (without explanation) as part of #15701 (an otherwise good PR). See discussion in #15701 (comment)

Additional Information

devel 1.5.1 e4e5a0c

links

• https://stackoverflow.com/a/12651825/1426932 (can be caused by multiple errors but restarting should work, as was done in actionRetry)