Signal a transient "partial input" failure from a placeholder hook

Placeholder resolve_expr (and validate_input) hooks should call ptr_signal_partial() – instead of rlang::abort() / stop() – when the current widget value is incomplete or transiently unparseable. Typical example: a free-text expr placeholder whose body has not finished being typed (mpg /). The condition carries class "ptr_partial_input".

Usage

ptr_signal_partial(message, ...)

Arguments

message: Diagnostic text. Surfaced on the gated plot path.
...: Additional named fields attached to the condition (forwarded to rlang::abort()).

Value

Never returns – always signals.

Details

ggpaintr's live reactive boundaries (column-picker entry_reactives that re-fire on every keystroke) catch this class and silently cancel the current re-render, so the downstream picker keeps its previous state instead of strobing blank and writing a Shiny warning to the R console. The Update / Draw-gated plot path does not catch it, so a value that is still partial when the user clicks "Update" still surfaces as a normal inline error.

Use ordinary rlang::abort() for failures that are NOT user mid-typing artifacts (security violations, real argument-shape errors, etc.).

Examples

# A resolve hook that treats an unfinished expression as a transient,
# silently-cancelled partial input rather than a hard error:
my_expr_resolve <- function(value, node, ...) {
  tryCatch(
    rlang::parse_expr(value),
    error = function(e) ptr_signal_partial(conditionMessage(e))
  )
}