From 70a110365c7106783abb4187f2d62957b339cf04 Mon Sep 17 00:00:00 2001
From: Davis Vaughan <davis@posit.co>
Date: Fri, 13 Jun 2025 15:41:06 -0400
Subject: [PATCH] Promote R `"parseError"` errors to `ParseResult::SyntaxError`

---
 crates/harp/src/error.rs |  7 ++--
 crates/harp/src/parse.rs | 89 +++++++++++++++++++++++++++++-----------
 2 files changed, 68 insertions(+), 28 deletions(-)

diff --git a/crates/harp/src/error.rs b/crates/harp/src/error.rs
index bf5b9077b..0d32ff7e4 100644
--- a/crates/harp/src/error.rs
+++ b/crates/harp/src/error.rs
@@ -46,7 +46,7 @@ pub enum Error {
     InvalidUtf8(Utf8Error),
     ParseSyntaxError {
         message: String,
-        line: i32,
+        line: Option<i32>,
     },
     MissingValueError,
     MissingColumnError {
@@ -200,8 +200,9 @@ impl fmt::Display for Error {
                 write!(f, "Invalid UTF-8 in string: {}", error)
             },
 
-            Error::ParseSyntaxError { message, line } => {
-                write!(f, "Syntax error on line {} when parsing: {}", line, message)
+            Error::ParseSyntaxError { message, line } => match line {
+                Some(line) => write!(f, "Syntax error on line {} when parsing: {}", line, message),
+                None => write!(f, "Syntax error when parsing: {}", message),
             },
 
             Error::MissingValueError => {
diff --git a/crates/harp/src/parse.rs b/crates/harp/src/parse.rs
index 7e819a8ca..782be99a0 100644
--- a/crates/harp/src/parse.rs
+++ b/crates/harp/src/parse.rs
@@ -28,7 +28,7 @@ pub struct RParseOptions {
 pub enum ParseResult {
     Complete(RObject),
     Incomplete,
-    SyntaxError { message: String, line: i32 },
+    SyntaxError { message: String, line: Option<i32> },
 }
 
 pub enum ParseInput<'a> {
@@ -109,25 +109,44 @@ pub fn parse_status<'a>(input: &ParseInput<'a>) -> crate::Result<ParseResult> {
             ParseInput::SrcFile(srcfile) => (srcfile.lines()?, srcfile.inner.clone()),
         };
 
-        let result: RObject =
-            try_catch(|| libr::R_ParseVector(text.sexp, -1, &mut status, srcfile.sexp).into())?;
-
-        match status {
-            libr::ParseStatus_PARSE_OK => Ok(ParseResult::Complete(result)),
-            libr::ParseStatus_PARSE_INCOMPLETE => Ok(ParseResult::Incomplete),
-            libr::ParseStatus_PARSE_ERROR => Ok(ParseResult::SyntaxError {
-                message: CStr::from_ptr(libr::get(libr::R_ParseErrorMsg).as_ptr())
-                    .to_string_lossy()
-                    .to_string(),
-                line: libr::get(libr::R_ParseError) as i32,
-            }),
-            _ => {
-                // Should not get here
-                Err(crate::Error::ParseError {
-                    code: parse_input_as_string(input)
-                        .unwrap_or(String::from("String conversion error")),
-                    message: String::from("Unknown parse error"),
-                })
+        let result: harp::Result<RObject> =
+            try_catch(|| libr::R_ParseVector(text.sexp, -1, &mut status, srcfile.sexp).into());
+
+        match result {
+            Ok(result) => match status {
+                libr::ParseStatus_PARSE_OK => Ok(ParseResult::Complete(result)),
+                libr::ParseStatus_PARSE_INCOMPLETE => Ok(ParseResult::Incomplete),
+                libr::ParseStatus_PARSE_ERROR => Ok(ParseResult::SyntaxError {
+                    message: CStr::from_ptr(libr::get(libr::R_ParseErrorMsg).as_ptr())
+                        .to_string_lossy()
+                        .to_string(),
+                    line: Some(libr::get(libr::R_ParseError) as i32),
+                }),
+                _ => {
+                    // Should not get here
+                    Err(crate::Error::ParseError {
+                        code: parse_input_as_string(input)
+                            .unwrap_or(String::from("String conversion error")),
+                        message: String::from("Unknown parse error"),
+                    })
+                },
+            },
+            Err(error) => match error {
+                // R's `raiseLexError()` or `raiseParseError()` throw classed R errors not
+                // captured by the `PARSE_ERROR` variant of `ParseStatus` above. We promote
+                // them to `ParseResult::SyntaxError` to simplify things for the caller.
+                // https://github.com/r-devel/r-svn/blob/78a15b0be74c14161edfa1da65137b0a74a36df6/src/main/gram.c#L6748
+                crate::Error::TryCatchError { message, class, .. }
+                    if class
+                        .as_ref()
+                        .is_some_and(|class| class.iter().any(|class| class == "parseError")) =>
+                {
+                    Ok(ParseResult::SyntaxError {
+                        message,
+                        line: None,
+                    })
+                },
+                error => Err(error),
             },
         }
     }
@@ -205,17 +224,37 @@ mod tests {
             );
 
             // Error
-            assert_match!(
-                parse_status(&ParseInput::Text("42 + _")),
-                Err(_) => {}
-            );
+            // TODO: Can we turn this into a parse error? It seems to happen because
+            // the parser calls `Rf_install()` to turn the name into a symbol, which
+            // throws its own R error that doesn't get classed as a "parseError". It
+            // currently shows a full backtrace because it looks like an unhandled error.
+            // https://github.com/posit-dev/ark/issues/598
+            assert_match!(parse_status(&ParseInput::Text("``")), Err(_));
 
             // "normal" syntax error
             assert_match!(
                 parse_status(&ParseInput::Text("1+1\n*42")),
                 Ok(ParseResult::SyntaxError {message, line}) => {
                     assert!(message.contains("unexpected"));
-                    assert_eq!(line, 2);
+                    assert_eq!(line, Some(2));
+                }
+            );
+
+            // `raiseParseError()` syntax error - pipe placeholder
+            assert_match!(
+                parse_status(&ParseInput::Text("42 + _")),
+                Ok(ParseResult::SyntaxError {message, line}) => {
+                    assert!(message.contains("pipe placeholder"));
+                    assert_eq!(line, None);
+                }
+            );
+
+            // `raiseParseError()` syntax error - unrecognized escape
+            assert_match!(
+                parse_status(&ParseInput::Text(r"'\s'")),
+                Ok(ParseResult::SyntaxError {message, line}) => {
+                    assert!(message.contains("unrecognized escape"));
+                    assert_eq!(line, None);
                 }
             );