R: Display backtrace on error

rlang_backtrace_on_error {rlang} | R Documentation

## Display backtrace on error

### Description

Errors thrown with `abort()` automatically save a backtrace that can be inspected by calling `last_error()`. Optionally, you can also display the backtrace alongside the error message by setting the option `rlang_backtrace_on_error` to one of the following values:

- `"reminder"`: Display a reminder that the backtrace can be inspected by calling `rlang::last_error()`.

- `"branch"`: Display a simplified backtrace.

- `"collapse"`: Display a collapsed backtrace tree.

- `"full"`: Display the full backtrace tree.

### Promote base errors to rlang errors

Call `options(error = rlang::entrace)` to instrument base errors with rlang features. This handler does two things:

- It saves the base error as an rlang object. This allows you to call `last_error()` to print the backtrace or inspect its data.

- It prints the backtrace for the current error according to the `rlang_backtrace_on_error` option.

### Examples

    # Display a simplified backtrace on error for both base and rlang
    # errors:

    # options(
    #   rlang_backtrace_on_error = "branch",
    #   error = rlang::entrace
    # )
    # stop("foo")

[Package rlang version 0.4.2 Index]