[Bug] rsync does not support custom remote ssh port

[alexrah]

Describe the bug

when setting a host with a port in deployment.lua

return {
  ["myremote"] = {
    host = "hostname:22250",
    username = "foo",
    mappings = {
      {
        ["local"] = "/",
        ["remote"] = "/",
      },
    },
  },
}

the host works as expected when operations are run through scp but they don't work using rsync.
The commands (based on rsync) lacking support are:

• TransferDownload or TransferUpload when path is a dir
• TransferDirDiff

How to reproduce

1. set host with syntax hostname:port
2. run either TransferDownload, TransferUpload on a dir or TransferDirDiff

Error shown:

Host key verification failed.
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255)

Expected behavior

• diff the directory with the remote one and display the changed files in the quickfix
• sync the files

System

• OS: MacOS 13.5.2
• NVIM v0.11.3
• transfer.nvim commit: af75ad5

Solution

• I'm working on a pull request with a modified remote_rsync_path() to extract port numbers from host strings
• rsync doesn't support hostname:portnumber syntax, but it requires to define the port using extended options, i.e. -e "ssh -p {portnumer}"
• to avoid command execution issues with extended options, need to pass a string instead of a list to vim.fn.jobstrart -> vim.fn.jobstart(table.concat(command, " "),{...})

Especially about the last point, do you think that could have some side effects?

[coffebar]

You need to set port in your ssh config only, not in plugin's config.

[alexrah]

well, the hostname:port syntax works already for scp based commands.
In my setup I connect to dozens of different servers through the same hostname with different ports, so it makes sense to have this feature.
Besides changing how the command is passed to vim.fn.jobstart the rest of the implementation doesn't change the overall logic, so if it's not too much trouble I would really appreciate if you take the time to review the pull request (still working on it).

[coffebar]

No problem, you can create a PR when ready