Check that profile path exists before sourcing (#967)

Author: lionel-

crates/ark/src/startup.rs

@@ -15,6 +15,7 @@ use harp::environment::R_ENVS;
 use harp::exec::RFunction;
 use harp::exec::RFunctionExt;
 use libr::Rf_eval;
+use stdext::result::ResultExt;
 
 use crate::interface::RMain;
 use crate::sys;
@@ -62,6 +63,11 @@ fn source_r_profile(path: &PathBuf) {
 
     log::info!("Found R profile at '{path}', sourcing now");
 
+    if !std::path::Path::new(path).exists() {
+        log::warn!("R profile at '{path}' does not exist, skipping source");
+        return;
+    }
+
     // Must source with `top_level_exec()` rather than just calling `call()`.
     // In particular, can't source with the typical `r_safe_eval()` because it
     // wraps in `withCallingHandlers()`, which prevents
@@ -105,7 +111,19 @@ fn source_r_profile(path: &PathBuf) {
 fn find_site_r_profile(r_home: &PathBuf) -> Option<PathBuf> {
     // Try from env var first
     match std::env::var("R_PROFILE") {
-        Ok(path) => return PathBuf::from_str(path.as_str()).ok(),
+        Ok(path) => {
+            if let Some(path) = PathBuf::from_str(path.as_str()).log_err() {
+                if !path.exists() {
+                    log::warn!(
+                        "`R_PROFILE` detected but '{path}' does not exist",
+                        path = path.to_string_lossy()
+                    );
+                    return None;
+                } else {
+                    return Some(path);
+                }
+            }
+        },
         Err(_) => (),
     };
 

crates/ark/tests/kernel-r-profile.rs

@@ -0,0 +1,106 @@
+use std::io::Write;
+
+use amalthea::fixtures::dummy_frontend::ExecuteRequestOptions;
+use ark::fixtures::DummyArkFrontendRprofile;
+
+// You must run these tests with `cargo nextest` because they initialise
+// incompatible process singletons
+
+/// See https://github.com/posit-dev/positron/issues/4973
+#[test]
+fn test_r_profile_can_cat() {
+    let message = "hi from rprofile";
+
+    // The `\n` is critical, otherwise R's `source()` silently fails
+    let contents = format!("cat('{message}')\n");
+
+    // Write `contents` to a tempfile that we declare to be
+    // the `.Rprofile` that R should use
+    let mut file = tempfile::NamedTempFile::new().unwrap();
+    write!(file, "{contents}").unwrap();
+
+    let path = file.path();
+    let path = path.to_str().unwrap();
+
+    unsafe { std::env::set_var("R_PROFILE_USER", path) };
+
+    // Ok, load up R now. It should `cat()` the `message` over iopub.
+    let frontend = DummyArkFrontendRprofile::lock();
+
+    frontend.recv_iopub_stream_stdout(message)
+}
+
+/// See https://github.com/posit-dev/positron/issues/4253
+#[test]
+fn test_r_profile_is_only_run_once() {
+    // The trailing `\n` is critical, otherwise R's `source()` silently fails
+    let contents = r#"
+if (exists("x")) {
+  x <- 2
+} else {
+  x <- 1
+}
+
+"#;
+
+    // Write `contents` to a tempfile that we declare to be
+    // the `.Rprofile` that R should use
+    let mut file = tempfile::NamedTempFile::new().unwrap();
+    write!(file, "{contents}").unwrap();
+
+    let path = file.path();
+    let path = path.to_str().unwrap();
+
+    unsafe { std::env::set_var("R_PROFILE_USER", path) };
+
+    // Ok, start R. If we've set everything correctly, R should not run
+    // the `.Rprofile`, but ark should - i.e. it should run exactly 1 time.
+    let frontend = DummyArkFrontendRprofile::lock();
+
+    frontend.send_execute_request("x", ExecuteRequestOptions::default());
+    frontend.recv_iopub_busy();
+
+    let input = frontend.recv_iopub_execute_input();
+    assert_eq!(input.code, "x");
+    assert_eq!(frontend.recv_iopub_execute_result(), "[1] 1");
+
+    frontend.recv_iopub_idle();
+
+    assert_eq!(frontend.recv_shell_execute_reply(), input.execution_count);
+}
+
+#[test]
+fn test_missing_user_profile() {
+    std::env::set_var("R_PROFILE_USER", "~/does/not/exist");
+
+    let frontend = DummyArkFrontendRprofile::lock();
+
+    frontend.send_execute_request("1", ExecuteRequestOptions::default());
+    frontend.recv_iopub_busy();
+
+    let input = frontend.recv_iopub_execute_input();
+    assert_eq!(input.code, "1");
+    assert_eq!(frontend.recv_iopub_execute_result(), "[1] 1");
+
+    frontend.recv_iopub_idle();
+
+    assert_eq!(frontend.recv_shell_execute_reply(), input.execution_count);
+}
+
+#[test]
+fn test_missing_site_profile() {
+    std::env::set_var("R_PROFILE", "~/does/not/exist");
+
+    let frontend = DummyArkFrontendRprofile::lock();
+
+    frontend.send_execute_request("1", ExecuteRequestOptions::default());
+    frontend.recv_iopub_busy();
+
+    let input = frontend.recv_iopub_execute_input();
+    assert_eq!(input.code, "1");
+    assert_eq!(frontend.recv_iopub_execute_result(), "[1] 1");
+
+    frontend.recv_iopub_idle();
+
+    assert_eq!(frontend.recv_shell_execute_reply(), input.execution_count);
+}