Format a Validation Error

Produces a consistently formatted error message and stops execution. Intended for use inside custom validation steps created with require_custom(), so they produce the same structured errors as built-in steps.

Usage

fail(path, message, found = NULL, at = NULL)

Arguments

path

the full path (e.g. "x" or "newdata$x2").

message

the specific failure message.

found

optional value to show on a Found: line.

at

optional integer positions to show on an At: line.

Value

No return value. Called for its side effect: it signals a classed restrictR_failure condition (an error) carrying path, message, and the optional found and at details.

Details

Format: path: message, with optional Found: and At: lines.

See also

Other core: as_contract_block(), as_contract_text(), is_valid(), require_custom(), restrict(), validation_errors()

Examples

# fail() signals an error; wrap in try() to show the formatted message
try(fail("x", "must be positive", found = -3, at = 2L))
#> Error : x: must be positive
#>   Found: -3
#>   At: 2