move bc_pvals check

Author: utkarshpawade

NEWS.md

@@ -1,6 +1,6 @@
 # bayesplot (development version)
 
-* Validate user-provided `pit` values in `ppc_loo_pit_data()` using `validate_pit()` to reject invalid inputs (non-numeric, out of range, NAs) at the entry point instead of in internal helpers.
+* Validate user-provided `pit` values in `ppc_loo_pit_data()` and `ppc_loo_pit_qq()`, rejecting non-numeric inputs, missing values, and values outside `[0, 1]`.
 * Fixed `is_chain_list()` to correctly reject empty lists instead of silently returning `TRUE`.
 * Added unit tests for `mcmc_areas_ridges_data()`, `mcmc_parcoord_data()`, and `mcmc_trace_data()`.
 * Added unit tests for `ppc_error_data()` and `ppc_loo_pit_data()` covering output structure, argument handling, and edge cases.

R/ppc-loo.R

@@ -811,15 +811,15 @@ ppc_loo_ribbon <-
   # 1-D Convolution
   bc_pvals <- .linear_convolution(x, bw, grid_counts, grid_breaks, grid_len)
 
+  if (all(is.na(bc_pvals))) {
+    abort("KDE boundary correction produced all NA values.")
+  }
+
   # Generate vector of x-axis values for plotting based on binned relative freqs
   n_breaks <- length(grid_breaks)
 
   xs <- (grid_breaks[2:n_breaks] + grid_breaks[1:(n_breaks - 1)]) / 2
 
-  if (all(is.na(bc_pvals))) {
-    abort("KDE boundary correction produced all NA values.")
-  }
-
   first_nonNA <- utils::head(which(!is.na(bc_pvals)), 1)
   last_nonNA <- utils::tail(which(!is.na(bc_pvals)), 1)
   bc_pvals[1:first_nonNA] <- bc_pvals[first_nonNA]