Move r_home_setup() to harp

crates/ark/src/interface.rs

@@ -55,6 +55,7 @@ use crossbeam::channel::Receiver;
 use crossbeam::channel::Sender;
 use crossbeam::select;
 use harp::command::r_command;
+use harp::command::r_home_setup;
 use harp::environment::r_ns_env;
 use harp::environment::Environment;
 use harp::environment::R_ENVS;
@@ -123,7 +124,6 @@ use crate::strings::lines;
 use crate::sys::console::console_to_utf8;
 use crate::ui::UiCommMessage;
 use crate::ui::UiCommSender;
-use crate::version::r_home_setup;
 
 static RE_DEBUG_PROMPT: Lazy<Regex> = Lazy::new(|| Regex::new(r"Browse\[\d+\]").unwrap());
 

crates/ark/src/version.rs

@@ -11,7 +11,7 @@ use std::path::PathBuf;
 
 use anyhow::Context;
 use harp::command::r_command;
-use harp::command::r_command_from_path;
+use harp::command::r_home_setup;
 use harp::object::RObject;
 use itertools::Itertools;
 use libr::SEXP;
@@ -31,31 +31,6 @@ pub struct RVersion {
     pub r_home: String,
 }
 
-pub(crate) fn r_home_setup() -> PathBuf {
-    match std::env::var("R_HOME") {
-        Ok(home) => {
-            // Get `R_HOME` from env var, typically set by Positron / CI / kernel specification
-            PathBuf::from(home)
-        },
-        Err(_) => {
-            // Get `R_HOME` from `PATH`, via `R`
-            let Ok(result) = r_command_from_path(|command| {
-                command.arg("RHOME");
-            }) else {
-                panic!("Can't find R or `R_HOME`");
-            };
-
-            let r_home = String::from_utf8(result.stdout).unwrap();
-            let r_home = r_home.trim();
-
-            // Now set `R_HOME`. From now on, `r_command()` can be used to
-            // run exactly the same R as is running in Ark.
-            unsafe { std::env::set_var("R_HOME", r_home) };
-            PathBuf::from(r_home)
-        },
-    }
-}
-
 pub fn detect_r() -> anyhow::Result<RVersion> {
     let r_home: String = r_home_setup().to_string_lossy().to_string();
 

crates/harp/src/command.rs

@@ -18,7 +18,8 @@ use crate::sys::command::COMMAND_R_NAMES;
 /// - For Windows, this looks at `R` (`R.exe`) and `R.bat` (for rig compatibility)
 ///
 /// The executable name is joined to the path in `R_HOME`. If not set, this is a
-/// panic. Use `r_command_from_path()` to exectute R from `PATH` instead.
+/// panic. Use `r_home_setup()` to set `R_HOME` from the R on the `PATH` or use
+/// `r_command_from_path()` to exectute R from `PATH` directly.
 ///
 /// Returns the `Ok()` value of the first success, or the `Err()` value of the
 /// last failure if all locations fail.
@@ -39,6 +40,32 @@ where
     r_command_from_locs(locations, build)
 }
 
+/// Use this before calling `r_command()` to ensure that `R_HOME` is set consistently
+pub fn r_home_setup() -> PathBuf {
+    match std::env::var("R_HOME") {
+        Ok(home) => {
+            // Get `R_HOME` from env var, typically set by Positron / CI / kernel specification
+            PathBuf::from(home)
+        },
+        Err(_) => {
+            // Get `R_HOME` from `PATH`, via `R`
+            let Ok(result) = r_command_from_path(|command| {
+                command.arg("RHOME");
+            }) else {
+                panic!("Can't find R or `R_HOME`");
+            };
+
+            let r_home = String::from_utf8(result.stdout).unwrap();
+            let r_home = r_home.trim();
+
+            // Now set `R_HOME`. From now on, `r_command()` can be used to
+            // run exactly the same R as is running in Ark.
+            unsafe { std::env::set_var("R_HOME", r_home) };
+            PathBuf::from(r_home)
+        },
+    }
+}
+
 /// Execute a `Command` for R found on the `PATH`
 ///
 /// This is like `r_command()` but doesn't assume `R_HOME` is defined.