Fix source() hook fallback with local = TRUE

crates/ark/src/modules/positron/hooks_source.R

@@ -38,6 +38,11 @@ make_ark_source <- function(original_source) {
         # fallback calls.
         use_file <- missing(exprs)
 
+        # Capture environment early if local evaluation is requested
+        if (isTRUE(local)) {
+            local <- parent.frame()
+        }
+
         # DRY: Promise for calling `original_source` with all arguments.
         # Evaluated lazily only when needed for fallback paths.
         delayedAssign(
@@ -87,6 +92,9 @@ make_ark_source <- function(original_source) {
         }
 
         env <- if (isTRUE(local)) {
+            # That would be very unexpected since we captured the local
+            # environment in `local` when set to `TRUE`. But just for peace of
+            # mind we handle it here.
             parent.frame()
         } else if (isFALSE(local)) {
             .GlobalEnv

crates/ark/tests/kernel-hooks-source.rs

@@ -0,0 +1,58 @@
+use std::io::Write;
+
+use ark::fixtures::DummyArkFrontend;
+
+#[test]
+fn test_source_local() {
+    let frontend = DummyArkFrontend::lock();
+
+    let mut file = tempfile::NamedTempFile::new().unwrap();
+    write!(file, "foobar\n").unwrap();
+
+    let path = file.path().to_str().unwrap();
+
+    // Breakpoint injection path
+    let code = format!(
+        r#"local({{
+    foobar <- "worked"
+    source("{path}", local = TRUE)$value
+}})"#
+    );
+
+    frontend.execute_request(&code, |result| {
+        assert_eq!(result, "[1] \"worked\"");
+    });
+
+    // Fallback path (because we supply `encoding`)
+    let code = format!(
+        r#"local({{
+    foobar <- "worked"
+    source("{path}", local = TRUE, encoding = "UTF-8")$value
+}})"#
+    );
+
+    frontend.execute_request(&code, |result| {
+        assert_eq!(result, "[1] \"worked\"");
+    });
+}
+
+#[test]
+fn test_source_local_fallback() {
+    let frontend = DummyArkFrontend::lock();
+
+    let mut file = tempfile::NamedTempFile::new().unwrap();
+    write!(file, "foobar\n").unwrap();
+
+    let path = file.path().to_str().unwrap();
+
+    let code = format!(
+        r#"local({{
+    foobar <- "worked"
+    source("{path}", local = TRUE, encoding = "UTF-8")$value
+}})"#
+    );
+
+    frontend.execute_request(&code, |result| {
+        assert_eq!(result, "[1] \"worked\"");
+    });
+}