fix validate_chain_list() colnames check to compare all chains

Author: utkarshpawade

R/helpers-mcmc.R

@@ -277,12 +277,8 @@ validate_chain_list <- function(x) {
       abort("Each chain should have the same number of iterations.")
     }
 
-    cnames <- sapply(x, colnames)
-    if (is.array(cnames)) {
-      same_params <- identical(cnames[, 1], cnames[, 2])
-    } else {
-      same_params <- length(unique(cnames)) == 1
-    }
+    cnames <- lapply(x, colnames)
+    same_params <- all(vapply(cnames[-1], identical, logical(1), cnames[[1]]))
     if (!same_params) {
       abort(paste(
         "The parameters for each chain should be in the same order",