Store trace into own error field

Author: lionel-

crates/harp/src/error.rs

@@ -25,6 +25,7 @@ pub enum Error {
     EvaluationError {
         code: String,
         message: String,
+        trace: String,
     },
     UnsafeEvaluationError(String),
     UnexpectedLength(usize, usize),
@@ -89,8 +90,18 @@ impl fmt::Display for Error {
                 write!(f, "Error parsing {}: {}", code, message)
             },
 
-            Error::EvaluationError { code, message } => {
-                write!(f, "Error evaluating {}: {}", code, message)
+            Error::EvaluationError {
+                code,
+                message,
+                trace,
+            } => {
+                let mut msg = format!("Error evaluating {code}: {message}");
+
+                if !trace.is_empty() {
+                    msg = format!("{msg}\nR backtrace:\n{trace}");
+                }
+
+                write!(f, "{msg}")
             },
 
             Error::UnsafeEvaluationError(code) => {

crates/harp/src/eval.rs

@@ -59,6 +59,7 @@ pub fn r_parse_eval(code: &str, options: RParseEvalOptions) -> Result<RObject> {
                 return Err(Error::EvaluationError {
                     code: code.to_string(),
                     message: geterrmessage(),
+                    trace: String::from(""),
                 });
             }
         }

crates/harp/src/exec.rs

@@ -120,7 +120,8 @@ pub fn r_safe_eval(expr: RObject, env: RObject) -> crate::Result<RObject> {
 
             return Err(Error::EvaluationError {
                 code,
-                message: message + "\nTrace:\n" + &trace,
+                message,
+                trace,
             });
         }
 
@@ -689,7 +690,7 @@ mod tests {
 
             assert_match!(result, Err(err) => {
                 let msg = format!("{err}");
-                let re = regex::Regex::new("Trace:\n(.|\n)*1L [+] \"\"").unwrap();
+                let re = regex::Regex::new("R backtrace:\n(.|\n)*1L [+] \"\"").unwrap();
                 assert!(re.is_match(&msg));
             });
         }