jobsend sends no data even though return code is 1?

Question

So I am trying to send some json text to a python script with jobsend in neovim like this:

let l:json_msg = json_encode(a:msg)
call jobsend(s:vimwatcher_job, l:json_msg)

If i echo l:json_msg I can see that the l:json_msg is a properly encoded string yet my program receives nothing from stdin at all.

If I run echo jobsend(s:vimwatcher_job, l:json_msg) I can see that the return code is 1 so it seems to succeed.

It works fine however in normal vim like this (without the encoding and setting the in_mode on job_start to "json")

call ch_sendexpr(s:vimwatcher_job, a:msg)

Any idea what could go wrong?

Answer 1

I was missing newlines, I assumed that jobsend appended newlines to each message since ch_sendexpr did but that was not the case.

Reading the documentation and stubling upon an example made me find the solution. When using ch_sendraw in normal vim I would also need newlines, so it all makes sense.