Merge pull request #1152 from stan-dev/revert-model_params-removal

Keep model_params to avoid breaking brms

Author: jgabry

NEWS.md

@@ -3,7 +3,6 @@
 * Removed deprecated items (replacements in parentheses):
   - `read_sample_csv()` (`read_cmdstan_csv()`)
   - `write_stan_tempfile()` (`write_stan_file()`)
-  - `model_params` element of `fit$metadata()` list (`variables` element)
   - `jacobian_adjustment` argument to `fit$log_prob()` and similar methods (`jacobian` argument)
   - `output_samples` argument to `model$variational()` (`draws` argument)
   - `hessian` argument to `fit$init_model_methods()` (`hessian` method always compiled now)

R/csv.R

@@ -328,7 +328,7 @@ read_cmdstan_csv <- function(files,
   model_param_dims <- variable_dims(metadata$variables)
   metadata$stan_variable_sizes <- model_param_dims
   metadata$stan_variables <- names(model_param_dims)
-
+  metadata$model_params <- metadata$variables # for backwards compatibility
   if (metadata$method == "sample") {
     if (is.null(format)) {
       format <- "draws_array"