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Stop with Better Error Messages

Source: R/stop2.R
stop2.Rd

A helper function that uses the best available error handling method. Tries to use cli::cli_abort() for rich formatting, falls back to rlang::abort() for better error handling, and ultimately uses base stop() if neither is available.

Usage

stop2(message, ..., .envir = parent.frame(), class = NULL)

Arguments

message

An error message string. Can include string interpolation using {variable} syntax which will be evaluated in .envir.

...

Additional arguments passed to the error function.

.envir

Environment for string interpolation. Defaults to parent frame.

class

Character vector of error classes (for cli and rlang).

Value

This function does not return; it stops execution with an error.

Details

This function implements a fallback mechanism for error handling:

  • If cli is available, uses cli_abort for rich, formatted error messages with color, styling support, and native string interpolation.

  • If cli is not available but rlang is, uses abort for structured error objects with better error handling capabilities.

  • If neither package is available, falls back to base R's stop with call. = FALSE to follow tidyverse style conventions.

String interpolation with {variable} syntax is always supported:

  • If cli is available, full cli interpolation and formatting features are used (including {.val}, {.field}, etc.).

  • If cli is not available but glue is, glue's interpolation engine is used, supporting {{{literal}}} escaping.

  • If neither package is available, a simple fallback interpolation handles basic {expression} syntax. This fallback does not support advanced features like {{{literal}}} escaping for literal braces, or cli's special formatting syntax.

See also

cli_abort, abort, stop

Examples

if (FALSE) { # \dontrun{
# Basic usage
stop2("Something went wrong")

# With variable interpolation (works regardless of installed packages)
x <- 5
stop2("Expected value < 3, got {x}")

# With expression interpolation
df <- data.frame(a = 1:3)
stop2("Expected 5 rows, got {nrow(df)}")

# With multiple interpolations
expected <- 10
actual <- 5
stop2("Expected {expected}, got {actual}")

# With custom error class
stop2("Invalid input", class = "invalid_input_error")
} # }