Ark: Move away from R startup pass through of -- towards explicit CLI arguments that we support

[DavisVaughan]

Right now, ark has an argument "pass through" method of -- that passes on any command line arguments to R

In Positron we set a few, like --interactive and --quiet and --no-restore-data, but the user has a chance to set some too:

This is actually absolutely not working as intended right now. On Windows, we aren't even passing these arguments through to R's cmdlinearg utility
https://github.com/posit-dev/ark/blob/d6ab389bb828db56850948f10b27e3161285be47/crates/ark/src/sys/windows/interface.rs#L55-L56

But here's the thing, I don't think we should. In RStudio, there is no option to just pass whatever flags you want through to R. RStudio exposes a UI to set blessed options, and then it does whatever internal magic is needed to mimic things like --no-init-file (which would be to set pRP->LoadInitFile = loadInitFile ? TRUE : FALSE, not to pass --no-init-file through to R directly).

This is a good thing because it would put ark in control over the limited set of blessed options you can tweak while starting R. For example, we'd never want anyone to pass -e to run a single expression and then exit.

Here is the set of ark options

--connection_file
--startup-file
--session-mode
--no-capture-streams
--version
--log
--install
--help

I think we should also add this explicit set of R options instead of --

--r-quiet

# These default to TRUE like R, so the flag name is `no`
--r-no-init-file
--r-no-site-file
--r-no-environ

# I vote we default these to FALSE internally, unlike R,
# which means we also remove the `"no"` from their R option name
--r-save
--r-restore-data
--r-restore-history

# Advanced user customization, sometimes for workbench / security
--r-max-connections=N
--r-max-ppsize=N
--r-min-nsize=N
--r-min-vsize=N

# Special, but common
# We would already _default_ to no-save, no-restore, so this would practically
# add no-init-file, no-site-file, no-environ
--r-vanilla

That is the complete list of what I think we should add as explicit options out of this set from R's help page:

Options:
  -h, --help            Print short help message and exit
  --version             Print version info and exit
  --encoding=ENC        Specify encoding to be used for stdin
  --encoding ENC
  RHOME			Print path to R home directory and exit
  --save                Do save workspace at the end of the session
  --no-save             Don't save it
  --no-environ          Don't read the site and user environment files
  --no-site-file        Don't read the site-wide Rprofile
  --no-init-file        Don't read the user R profile
  --restore             Do restore previously saved objects at startup
  --no-restore-data     Don't restore previously saved objects
  --no-restore-history  Don't restore the R history file
  --no-restore          Don't restore anything
  --vanilla		Combine --no-save, --no-restore, --no-site-file,
			--no-init-file and --no-environ
  --no-readline         Don't use readline for command-line editing
  --max-connections=N   Set max number of connections to N
  --max-ppsize=N        Set max size of protect stack to N
  --min-nsize=N         Set min number of fixed size obj's ("cons cells") to N
  --min-vsize=N         Set vector heap minimum to N bytes; '4M' = 4 MegaB
  -q, --quiet           Don't print startup message
  --silent              Same as --quiet
  -s, --no-echo         Make R run as quietly as possible
  --interactive         Force an interactive session
  --verbose             Print more information about progress
  -d, --debugger=NAME   Run R through debugger NAME
  --debugger-args=ARGS  Pass ARGS as arguments to the debugger
  -g TYPE, --gui=TYPE	Use TYPE as GUI; possible values are 'X11' (default)
			and 'Tk'.
  --arch=NAME		Specify a sub-architecture
  --args                Skip the rest of the command line
  -f FILE, --file=FILE  Take input from 'FILE'
  -e EXPR               Execute 'EXPR' and exit

[DavisVaughan]

clap-rs/clap#3513 has an example of argument namespacing like we'd want here. something like

ark

USAGE:
    ark [OPTIONS] [R OPTIONS]

OPTIONS:
    -h, --help                         Print help information
    --some-string 

R OPTIONS:
        --r.quiet 

Do we prefer underscore or dashes? r.no_init_file or r.no-init-file? I think we are locked in to connection_file through jupyter, so maybe we should use underscore everywhere for consistency.

[jennybc]

The main argument I didn't see explicitly called out above (it's in the list, of course) that I think features prominently in R lore is --vanilla. I know it's just a combination of several specific options, but I think the --vanilla combo pack would be nice to expose explicitly in UI/docs as a familiar shorthand for a certain set of flags.

[kevinushey]

Do we prefer underscore or dashes? r.no_init_file or r.no-init-file? I think we are locked in to connection_file through jupyter, so maybe we should use underscore everywhere for consistency.

I personally prefer the dashes. I can't think of any other tools which use _ as a separator for command line arguments. I also prefer having the names match the R equivalents as closely as possible, so we shouldn't transform those separators just for internal consistency. My vote would be for --r.no-save and --r.no-init-file.

[DavisVaughan]

Oh you know what, the jupyter spec says we just need this --connection-file {connection_file} - i.e. the arg name can be separated by a dash as long as the templated thing has the underscore.

So I think we can fully standardize on an underscore everywhere.

Agree that --r.no-init-file is pretty nice for matching the R equivalent closely

[jmcphers]

In RStudio, there is no option to just pass whatever flags you want through to R.

There isn't, but people have repeatedly asked for it, which is why I added the passthrough to Ark originally. Some Workbench customers have asked for the ability to set e.g. --min-vsize and we just have to say "sorry, you can't".

Totally fine with removing the ability to set any command line arg you want, but some people do want to control allocation behavior so I'd suggest adding the max/min flags.