Make growth_rate(method = "trendfilter") without {trendfilter} a hard error

Author: brookslogan

NEWS.md

@@ -11,9 +11,9 @@ Pre-1.0.0 numbering scheme: 0.x will indicate releases, while 0.x.y will indicat
   than before. In order to make `{epiprocess}` installation easier for users
   without a compiler, we have placed `{trendfilter}` in Suggests:; if you want
   to use `method = "trendfilter"` you will need to manually this dependency
-  (e.g., with `remotes::install_github("glmgen/trendfilter")`). The interface for
-  passing arguments to the `"smooth_spline"` and `"trend_filter"` methods has
-  also changed.
+  (e.g., with `remotes::install_github("glmgen/trendfilter")`). The interface
+  for passing arguments to the `"smooth_spline"` and `"trend_filter"` methods
+  has also changed.
 - In `revision_summary()`:
   - Output now uses the name `lag_near_latest` instead of `time_near_latest`. To
     migrate, update references to `time_near_latest` to `lag_near_latest`.

R/growth_rate.R

@@ -52,8 +52,7 @@
 #'   [trendfilter::trendfilter()], divided by the fitted value of the discrete
 #'   spline at `x0`. This method requires the
 #'   [`{trendfilter}` package](https://github.com/glmgen/trendfilter)
-#'   to be installed (if it isn't, `method = "rel_change"` will be used and a
-#'   warning issued).
+#'   to be installed.
 #'
 #' ## Log Scale
 #'
@@ -139,11 +138,9 @@ growth_rate <- function(
     )
   }
   if (method == "trend_filter" && !requireNamespace("trendfilter", quietly = TRUE)) {
-    method <- "rel_change"
-    cli_warn(c(
+    cli_abort(c(
       "The {.pkg trendfilter} package must be installed to use this option.",
-      i = "It is available at {.url https://github.com/glmgen/trendfilter}.",
-      i = 'The computation will proceed using `method = "rel_change"` instead.'
+      i = "It is available at {.url https://github.com/glmgen/trendfilter}."
     ))
   }