fix(repl): errors shouldn't terminate repl (#17082)

This commit changes REPL to never surface errors coming
from code execution, but instead print them as errors
to the REPL itself.

cli/tests/repl_tests.rs

@@ -940,7 +940,7 @@ mod repl {
         true,
         vec!["repl", "--quiet", "--allow-read", "--allow-env"],
         Some(vec![r#"export {} from "npm:chalk";"#]),
-        Some(env_vars),
+        Some(env_vars.clone()),
         true,
       );
 
@@ -948,5 +948,21 @@ mod repl {
       assert_contains!(out, "Chalk: [Function: Chalk],");
       assert!(err.is_empty());
     }
+
+    {
+      let (out, err) = util::run_and_collect_output_with_args(
+        true,
+        vec!["repl", "--quiet", "--allow-read", "--allow-env"],
+        Some(vec![r#"import foo from "npm:asdfawe52345asdf""#]),
+        Some(env_vars),
+        true,
+      );
+
+      assert_contains!(
+        out,
+        "error: npm package 'asdfawe52345asdf' does not exist"
+      );
+      assert!(err.is_empty());
+    }
   }
 }

cli/tools/repl/mod.rs

@@ -107,7 +107,7 @@ pub async fn run(flags: Flags, repl_flags: ReplFlags) -> Result<i32, AnyError> {
         Ok(eval_source) => {
           let output = repl_session
             .evaluate_line_and_get_output(&eval_source)
-            .await?;
+            .await;
           // only output errors
           if let EvaluationOutput::Error(error_text) = output {
             println!(
@@ -124,7 +124,7 @@ pub async fn run(flags: Flags, repl_flags: ReplFlags) -> Result<i32, AnyError> {
   }
 
   if let Some(eval) = repl_flags.eval {
-    let output = repl_session.evaluate_line_and_get_output(&eval).await?;
+    let output = repl_session.evaluate_line_and_get_output(&eval).await;
     // only output errors
     if let EvaluationOutput::Error(error_text) = output {
       println!("Error in --eval flag: {}", error_text);
@@ -156,7 +156,7 @@ pub async fn run(flags: Flags, repl_flags: ReplFlags) -> Result<i32, AnyError> {
       Ok(line) => {
         should_exit_on_interrupt = false;
         editor.update_history(line.clone());
-        let output = repl_session.evaluate_line_and_get_output(&line).await?;
+        let output = repl_session.evaluate_line_and_get_output(&line).await;
 
         // We check for close and break here instead of making it a loop condition to get
         // consistent behavior in when the user evaluates a call to close().

cli/tools/repl/session.rs

@@ -68,6 +68,17 @@ impl std::fmt::Display for EvaluationOutput {
   }
 }
 
+pub fn result_to_evaluation_output(
+  r: Result<EvaluationOutput, AnyError>,
+) -> EvaluationOutput {
+  match r {
+    Ok(value) => value,
+    Err(err) => {
+      EvaluationOutput::Error(format!("{} {}", colors::red("error:"), err))
+    }
+  }
+}
+
 struct TsEvaluateResponse {
   ts_code: String,
   value: cdp::EvaluateResponse,
@@ -169,7 +180,7 @@ impl ReplSession {
   pub async fn evaluate_line_and_get_output(
     &mut self,
     line: &str,
-  ) -> Result<EvaluationOutput, AnyError> {
+  ) -> EvaluationOutput {
     fn format_diagnostic(diagnostic: &deno_ast::Diagnostic) -> String {
       format!(
         "{}: {} at {}:{}",
@@ -180,7 +191,11 @@ impl ReplSession {
       )
     }
 
-    match self.evaluate_line_with_object_wrapping(line).await {
+    async fn inner(
+      session: &mut ReplSession,
+      line: &str,
+    ) -> Result<EvaluationOutput, AnyError> {
+      match session.evaluate_line_with_object_wrapping(line).await {
         Ok(evaluate_response) => {
           let cdp::EvaluateResponse {
             result,
@@ -188,7 +203,7 @@ impl ReplSession {
           } = evaluate_response.value;
 
           Ok(if let Some(exception_details) = exception_details {
-          self.set_last_thrown_error(&result).await?;
+            session.set_last_thrown_error(&result).await?;
             let description = match exception_details.exception {
               Some(exception) => exception
                 .description
@@ -200,13 +215,13 @@ impl ReplSession {
               exception_details.text, description
             ))
           } else {
-          self
+            session
               .language_server
               .commit_text(&evaluate_response.ts_code)
               .await;
 
-          self.set_last_eval_result(&result).await?;
+            session.set_last_eval_result(&result).await?;
-          let value = self.get_eval_value(&result).await?;
+            let value = session.get_eval_value(&result).await?;
             EvaluationOutput::Value(value)
           })
         }
@@ -232,6 +247,10 @@ impl ReplSession {
       }
     }
 
+    let result = inner(self, line).await;
+    result_to_evaluation_output(result)
+  }
+
   async fn evaluate_line_with_object_wrapping(
     &mut self,
     line: &str,