Merge branch 'refactor/sapply-to-vapply-type-safety' of https://github.com/utkarshpawade/bayesplot into pr/517

Author: jgabry

.github/workflows/test-coverage.yaml

@@ -40,7 +40,7 @@ jobs:
           covr::to_cobertura(cov)
         shell: Rscript {0}
 
-      - uses: codecov/codecov-action@v5
+      - uses: codecov/codecov-action@v6
         with:
           # Fail if error if not on PR, or if on PR and token is given
           fail_ci_if_error: ${{ github.event_name != 'pull_request' || secrets.CODECOV_TOKEN }}

NEWS.md

@@ -1,6 +1,6 @@
 # bayesplot (development version)
 
-* Replace 9 uses of `sapply()` with `vapply()` to enforce return types and prevent silent `list()` returns on zero-length input.
+* 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.
 * Added vignette sections demonstrating `*_data()` companion functions for building custom ggplot2 visualizations (#435)

R/helpers-mcmc.R

@@ -247,6 +247,9 @@ df_with_chain2array <- function(x) {
 #' @param x object to check
 #' @return TRUE or FALSE
 is_chain_list <- function(x) {
+  if (length(x) == 0) {
+    return(FALSE)
+  }
   check1 <- !is.data.frame(x) && is.list(x)
   dims <- try(vapply(x, function(chain) length(dim(chain)), integer(1)), silent=TRUE)
   if (inherits(dims, "try-error")) {

tests/testthat/test-helpers-mcmc.R

@@ -156,6 +156,7 @@ test_that("is_chain_list works", {
   expect_true(is_chain_list(chainlist))
   expect_true(is_chain_list(chainlist1))
   expect_true(is_chain_list(chainlist1chain))
+  expect_false(is_chain_list(list()))
 })
 
 test_that("validate_chain_list works", {