Error::as_highlighted panics when formatting a JsError with column_number = 0 #422

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1. xc01

   closed this as completedon May 27, 2026
2. xc01

   reopened this on May 27, 2026
3. xc01

   changed the title [-]as_highlighted panics when formatting a JsError with column_number = 0[/-] [+]Error::as_highlighted panics when formatting a JsError with column_number = 0[/+] on May 27, 2026
4. xc01 commented on May 27, 2026

   

   xc01

   on May 27, 2026

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   Describe the bug

   Error::as_highlighted() assumes that JsStackFrame::column_number is always 1-based.

   If a JsError contains a stack frame with column_number: Some(0), as_highlighted() panics while formatting the error:

   thread '...' panicked at src/error.rs:139:23:
   attempt to subtract with overflow
   

   The panic happens here:

   let col = usize::try_from(f.column_number.unwrap_or(1)).unwrap_or_default();
   let col = col - 1;

   This is an error-reporting path: as_highlighted() is used to output JS errors. Even if column 0 is unexpected metadata, the formatter should fall back to a normal error display instead of turning the original JS error into a Rust panic.

   To Reproduce

   use rustyscript::error::ErrorFormattingOptions;
   use rustyscript::Error;
   
   #[test]
   #[should_panic]
   fn panic_when_highlighting_js_error_with_zero_column() {
       let js_error = deno_core::error::JsError {
           name: Some("ReferenceError".to_string()),
           message: Some("x is not defined".to_string()),
           stack: None,
           cause: None,
           exception_message: "Uncaught ReferenceError: x is not defined".to_string(),
           frames: vec![deno_core::error::JsStackFrame {
               type_name: None,
               function_name: None,
               method_name: None,
               file_name: Some("file:///test.js".to_string()),
               line_number: Some(1),
               column_number: Some(0),
               eval_origin: None,
               is_top_level: Some(true),
               is_eval: false,
               is_native: false,
               is_constructor: false,
               is_async: false,
               is_promise_all: false,
               promise_index: None,
           }],
           source_line: Some("const x = y;".to_string()),
           source_line_frame_index: Some(0),
           aggregated: None,
           additional_properties: vec![],
       };
   
       let err = Error::from(js_error);
       let _ = err.as_highlighted(ErrorFormattingOptions::default());
   }

   Expected behavior

   as_highlighted() should not panic while formatting an error.

   If the column metadata is 0 or otherwise invalid, it should gracefully fall back to a safe column value or to normal non-highlighted error output.

   One possible fix is to avoid subtracting from zero:

   let col = usize::try_from(f.column_number.unwrap_or(1))
       .unwrap_or_default()
       .saturating_sub(1);

   or explicitly treat column_number == 0 as invalid and skip source highlighting.

   Desktop

   OS: Ubuntu 22.04.1
   Version: 0.12.3

   Additional context

   The issue is not that column 0 must be considered a valid source column. The concern is that as_highlighted() is part of the JS error display path, so malformed or edge-case stack-frame metadata should not turn an already captured JavaScript error into a Rust panic.