R outputs to standard out, which breaks FsAutoComplete

[rneatherway]

Ref: https://github.com/fsharp/emacs-fsharp-mode/issues/33

The R output on standard out is interleaved with the JSON messages being sent to the editors. I'd like to explore whether we can prevent these spurious messages from being printed here.

[rneatherway]

Example of output:

[[425]]
[[425]]$name
[1] "findPackageEnv"

[[425]]$type
[1] "closure"

[[425]]$params
[[425]]$params[[1]]
[1] "info"

[tpetricek]

This is mysterious - we must just be accidentally printing this somewhere - e.g. a leftover of some debugging attempts!

As documented here, the R provider starts a separate process (see here) that actually runs R and so I don't see how output from R could accidentally get into the output of the console that is calling the main type provider library.

[jmp75]

Let me know if I can do something with the AutoPrint behavior. It's been unfortunately an occasional practical stumbling block for users on different fronts whether it defaults to true or false.

[ghost]

@tpetricek The issue is solved.
R sometimes could still break autocomplete by sendng warning messages but it's easy to suppress those warning from R. Thanks for helps.

[tpetricek]

@jmp75 I think the AutoPrint behavior is fine as it is - the fact that we can enable/disable it when creating the engine is really all we need in R provider :-).

[ghost]

It happens again. I have no idea where the output comes from so I can't suppress it: Error: F# completion process produced malformed JSON (Loading required package: spd). Loading any packages causes this. I tried several R packages: Rcpp, spatial, spd.

[tpetricek]

Reopening. Is there a good way of getting a log of what gets sent to the FsAutoComplete so that I can more easily reproduce this?

[rneatherway]

@tpetricek the easiest way I found to reproduce it was with FsAutoComplete standalone, see this comment: https://github.com/fsharp/emacs-fsharp-mode/issues/33#issuecomment-156422321

I am really interested to know if there is some way FsAutoComplete can just suppress subprocesses from outputting, as otherwise this could keep happening.