From 43bbddbf9e2290e26adf2f1595ddd930bc8faa08 Mon Sep 17 00:00:00 2001
From: bernie gray <bfgray3@users.noreply.github.com>
Date: Sat, 9 Jun 2018 16:07:41 -0400
Subject: [PATCH] Throw informative error for glance.rqs. Closes #330. (#338)

---
 R/rq_tidiers.R           | 11 ++++++++++-
 tests/testthat/test-rq.R |  6 ++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/R/rq_tidiers.R b/R/rq_tidiers.R
index 72795f259..0f2e07eac 100644
--- a/R/rq_tidiers.R
+++ b/R/rq_tidiers.R
@@ -78,6 +78,10 @@ tidy.nlrq <- function(x, conf.int = FALSE, conf.level = 0.95, ...) {
 
 #' @rdname rq_tidiers
 #'
+#' @details Only models with a single \code{tau} value may be passed.
+#'   For multiple values, please use a \code{purrr::map} workflow instead,
+#'   e.g. \code{taus %>% map(function(tau_val) rq(y ~ x, tau = tau_val)) %>% map_dfr(glance)}.
+#'
 #' @return \code{glance.rq} returns one row for each quantile (tau)
 #' with the columns:
 #'  \item{tau}{quantile estimated}
@@ -99,7 +103,12 @@ glance.rq <- function(x, ...) {
 }
 
 #' @export
-glance.rqs <- glance.rq
+glance.rqs <- function(x, ...) {
+  stop("`glance` cannot handle objects of class 'rqs',",
+       " i.e. models with more than one tau value. Please",
+       " use a `purr::map`-based workflow with 'rq' models instead.",
+       call. = FALSE)
+}
 
 #' @rdname rq_tidiers
 #'
diff --git a/tests/testthat/test-rq.R b/tests/testthat/test-rq.R
index a52b13d66..2327f6dc4 100644
--- a/tests/testthat/test-rq.R
+++ b/tests/testthat/test-rq.R
@@ -29,6 +29,12 @@ test_that("rqs tidiers work", {
   td <- tidy(fit)
   check_tidy(td, exp.row = 114, exp.col = 5)
 
+  rqs_glance_error <- paste("`glance` cannot handle objects of class 'rqs',",
+                            "i.e. models with more than one tau value. Please",
+                            "use a `purr::map`-based workflow with 'rq' models instead.")
+
+  expect_error(glance(fit), regexp = rqs_glance_error)
+
   au <- augment(fit)
   check_tidy(au, exp.row = 2109, exp.col = 9)