From 508e1bc315789a7c3ae37226830da3647647ee25 Mon Sep 17 00:00:00 2001
From: Bernie Gray <bfgray3@gmail.com>
Date: Mon, 6 May 2019 23:40:31 -0400
Subject: [PATCH 01/12] default formula argument to NULL in geom_smooth();
 closes #3205

---
 NEWS.md            |  2 ++
 R/geom-smooth.r    |  2 +-
 R/stat-smooth.r    | 11 +++++++----
 man/geom_smooth.Rd |  8 +++++---
 4 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 4699714a4a..3865e33b17 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -66,6 +66,8 @@ core developer team.
 
 ## Minor improvements and bug fixes
 
+* The `formula` argument to `geom_smooth()` now defaults to `NULL` and is filled in with the approprate formula in the function body (@bfgray3, #3205).
+
 * `cut_width()` now accepts `...` to pass further arguments to `base::cut.default()`
    like `cut_number()` and `cut_interval()` already did (@cderv, #3055)
 
diff --git a/R/geom-smooth.r b/R/geom-smooth.r
index 6c10e98ba5..ceefaa2eea 100644
--- a/R/geom-smooth.r
+++ b/R/geom-smooth.r
@@ -79,7 +79,7 @@ geom_smooth <- function(mapping = NULL, data = NULL,
                         stat = "smooth", position = "identity",
                         ...,
                         method = "auto",
-                        formula = y ~ x,
+                        formula = NULL,
                         se = TRUE,
                         na.rm = FALSE,
                         show.legend = NA,
diff --git a/R/stat-smooth.r b/R/stat-smooth.r
index fecc2842e1..4434cd02ec 100644
--- a/R/stat-smooth.r
+++ b/R/stat-smooth.r
@@ -13,7 +13,9 @@
 #'   model that `method = "auto"` would use, then set
 #'   `method = "gam", formula = y ~ s(x, bs = "cs")`.
 #' @param formula Formula to use in smoothing function, eg. `y ~ x`,
-#'   `y ~ poly(x, 2)`, `y ~ log(x)`
+#'   `y ~ poly(x, 2)`, `y ~ log(x)`. `NULL` by default, in which case
+#'   `method = "auto"` implies `formula = y ~ x` when there are fewer than 1,000
+#'   observations and `formula = y ~ s(x, bs = "cs")` otherwise.
 #' @param se Display confidence interval around smooth? (`TRUE` by default, see
 #'   `level` to control.)
 #' @param fullrange Should the fit span the full range of the plot, or just
@@ -38,7 +40,7 @@ stat_smooth <- function(mapping = NULL, data = NULL,
                         geom = "smooth", position = "identity",
                         ...,
                         method = "auto",
-                        formula = y ~ x,
+                        formula = NULL,
                         se = TRUE,
                         n = 80,
                         span = 0.75,
@@ -86,9 +88,10 @@ StatSmooth <- ggproto("StatSmooth", Stat,
 
       if (max_group < 1000) {
         params$method <- "loess"
+        params$formula <- params$formula %||% (y ~ x)
       } else {
         params$method <- "gam"
-        params$formula <- y ~ s(x, bs = "cs")
+        params$formula <- params$formula %||% (y ~ s(x, bs = "cs"))
       }
       message("`geom_smooth()` using method = '", params$method,
               "' and formula '", deparse(params$formula), "'")
@@ -100,7 +103,7 @@ StatSmooth <- ggproto("StatSmooth", Stat,
     params
   },
 
-  compute_group = function(data, scales, method = "auto", formula = y~x,
+  compute_group = function(data, scales, method = "auto", formula = NULL,
                            se = TRUE, n = 80, span = 0.75, fullrange = FALSE,
                            xseq = NULL, level = 0.95, method.args = list(),
                            na.rm = FALSE) {
diff --git a/man/geom_smooth.Rd b/man/geom_smooth.Rd
index b1e0f69682..3e3e54c45d 100644
--- a/man/geom_smooth.Rd
+++ b/man/geom_smooth.Rd
@@ -6,11 +6,11 @@
 \title{Smoothed conditional means}
 \usage{
 geom_smooth(mapping = NULL, data = NULL, stat = "smooth",
-  position = "identity", ..., method = "auto", formula = y ~ x,
+  position = "identity", ..., method = "auto", formula = NULL,
   se = TRUE, na.rm = FALSE, show.legend = NA, inherit.aes = TRUE)
 
 stat_smooth(mapping = NULL, data = NULL, geom = "smooth",
-  position = "identity", ..., method = "auto", formula = y ~ x,
+  position = "identity", ..., method = "auto", formula = NULL,
   se = TRUE, n = 80, span = 0.75, fullrange = FALSE,
   level = 0.95, method.args = list(), na.rm = FALSE,
   show.legend = NA, inherit.aes = TRUE)
@@ -60,7 +60,9 @@ model that \code{method = "auto"} would use, then set
 \code{method = "gam", formula = y ~ s(x, bs = "cs")}.}
 
 \item{formula}{Formula to use in smoothing function, eg. \code{y ~ x},
-\code{y ~ poly(x, 2)}, \code{y ~ log(x)}}
+\code{y ~ poly(x, 2)}, \code{y ~ log(x)}. \code{NULL} by default, in which case
+\code{method = "auto"} implies \code{formula = y ~ x} when there are fewer than 1,000
+observations and \code{formula = y ~ s(x, bs = "cs")} otherwise.}
 
 \item{se}{Display confidence interval around smooth? (\code{TRUE} by default, see
 \code{level} to control.)}

From 4bb34e354c46aebc7f218c37ee5cc9bc75afbb9d Mon Sep 17 00:00:00 2001
From: Bernie Gray <bfgray3@gmail.com>
Date: Mon, 13 May 2019 20:39:24 -0400
Subject: [PATCH 02/12] remove news bullet for now since deadline for release
 has passed

---
 NEWS.md | 2 --
 1 file changed, 2 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 3865e33b17..4699714a4a 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -66,8 +66,6 @@ core developer team.
 
 ## Minor improvements and bug fixes
 
-* The `formula` argument to `geom_smooth()` now defaults to `NULL` and is filled in with the approprate formula in the function body (@bfgray3, #3205).
-
 * `cut_width()` now accepts `...` to pass further arguments to `base::cut.default()`
    like `cut_number()` and `cut_interval()` already did (@cderv, #3055)
 

From 04b3327106d8e7c2e7de544a6136ed32da2bfcb7 Mon Sep 17 00:00:00 2001
From: Bernie Gray <bfgray3@gmail.com>
Date: Mon, 13 May 2019 20:43:51 -0400
Subject: [PATCH 03/12] handle NULL formulas more carefully in geom_smooth()

---
 R/stat-smooth.r | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/R/stat-smooth.r b/R/stat-smooth.r
index 4434cd02ec..5c79e3b1fd 100644
--- a/R/stat-smooth.r
+++ b/R/stat-smooth.r
@@ -98,6 +98,9 @@ StatSmooth <- ggproto("StatSmooth", Stat,
     }
     if (identical(params$method, "gam")) {
       params$method <- mgcv::gam
+      params$formula <- y ~ s(x, bs = "cs")
+    } else {
+      params$formula <- params$formula %||% (y ~ x)
     }
 
     params

From bf963db8637294b8896553fcc056af4e61e9ca67 Mon Sep 17 00:00:00 2001
From: Bernie Gray <bfgray3@gmail.com>
Date: Mon, 13 May 2019 20:51:59 -0400
Subject: [PATCH 04/12] respect input formuals in geom_smooth()

---
 R/stat-smooth.r | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/R/stat-smooth.r b/R/stat-smooth.r
index 5c79e3b1fd..0275665519 100644
--- a/R/stat-smooth.r
+++ b/R/stat-smooth.r
@@ -98,7 +98,7 @@ StatSmooth <- ggproto("StatSmooth", Stat,
     }
     if (identical(params$method, "gam")) {
       params$method <- mgcv::gam
-      params$formula <- y ~ s(x, bs = "cs")
+      params$formula <- params$formula %||% y ~ s(x, bs = "cs")
     } else {
       params$formula <- params$formula %||% (y ~ x)
     }

From c4ce320b1ecd15049bdf7a2046d13187ee87e1a4 Mon Sep 17 00:00:00 2001
From: Bernie Gray <bfgray3@gmail.com>
Date: Thu, 30 May 2019 21:52:35 -0400
Subject: [PATCH 05/12] add parens around formula on rhs of %||%

---
 R/stat-smooth.r | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/R/stat-smooth.r b/R/stat-smooth.r
index 0275665519..1124548566 100644
--- a/R/stat-smooth.r
+++ b/R/stat-smooth.r
@@ -98,7 +98,7 @@ StatSmooth <- ggproto("StatSmooth", Stat,
     }
     if (identical(params$method, "gam")) {
       params$method <- mgcv::gam
-      params$formula <- params$formula %||% y ~ s(x, bs = "cs")
+      params$formula <- params$formula %||% (y ~ s(x, bs = "cs"))
     } else {
       params$formula <- params$formula %||% (y ~ x)
     }

From c9644c36070ddf961b8737a7a521c7603c5b743d Mon Sep 17 00:00:00 2001
From: Bernie Gray <bfgray3@gmail.com>
Date: Tue, 4 Jun 2019 21:13:49 -0400
Subject: [PATCH 06/12] only set formula once the method is known

---
 R/stat-smooth.r | 2 --
 1 file changed, 2 deletions(-)

diff --git a/R/stat-smooth.r b/R/stat-smooth.r
index 1124548566..c5cc964e0b 100644
--- a/R/stat-smooth.r
+++ b/R/stat-smooth.r
@@ -88,10 +88,8 @@ StatSmooth <- ggproto("StatSmooth", Stat,
 
       if (max_group < 1000) {
         params$method <- "loess"
-        params$formula <- params$formula %||% (y ~ x)
       } else {
         params$method <- "gam"
-        params$formula <- params$formula %||% (y ~ s(x, bs = "cs"))
       }
       message("`geom_smooth()` using method = '", params$method,
               "' and formula '", deparse(params$formula), "'")

From 0c2826b0560108908b56462b61c481e32a446aa9 Mon Sep 17 00:00:00 2001
From: Bernie Gray <bfgray3@gmail.com>
Date: Thu, 13 Jun 2019 23:14:31 -0400
Subject: [PATCH 07/12] refactor

---
 R/geom-smooth.r    |  4 ++--
 R/stat-smooth.r    | 48 +++++++++++++++++++++++++++++++---------------
 man/geom_smooth.Rd | 18 +++++++++--------
 3 files changed, 45 insertions(+), 25 deletions(-)

diff --git a/R/geom-smooth.r b/R/geom-smooth.r
index ceefaa2eea..da992e8305 100644
--- a/R/geom-smooth.r
+++ b/R/geom-smooth.r
@@ -78,7 +78,7 @@
 geom_smooth <- function(mapping = NULL, data = NULL,
                         stat = "smooth", position = "identity",
                         ...,
-                        method = "auto",
+                        method = NULL,
                         formula = NULL,
                         se = TRUE,
                         na.rm = FALSE,
@@ -91,7 +91,7 @@ geom_smooth <- function(mapping = NULL, data = NULL,
     ...
   )
   if (identical(stat, "smooth")) {
-    params$method <- method
+    params$method <- if (!is.null(method) && identical(method, "auto")) NULL else method
     params$formula <- formula
   }
 
diff --git a/R/stat-smooth.r b/R/stat-smooth.r
index c5cc964e0b..211acde24a 100644
--- a/R/stat-smooth.r
+++ b/R/stat-smooth.r
@@ -1,8 +1,10 @@
-#' @param method Smoothing method (function) to use, accepts either a character vector,
-#'   e.g. `"auto"`, `"lm"`, `"glm"`, `"gam"`, `"loess"` or a function, e.g.
-#'   `MASS::rlm` or `mgcv::gam`, `base::lm`, or `base::loess`.
+#' @param method Smoothing method (function) to use, accepts either
+#'   `NULL` or a character vector, e.g. `"lm"`, `"glm"`, `"gam"`, `"loess"`
+#'   or a function, e.g. `MASS::rlm` or `mgcv::gam`, `stats::lm`, or `stats::loess`.
+#'   `"auto"` is also accepted for backwards compatibility.  It is equivalent to
+#'   `NULL`.
 #'
-#'   For `method = "auto"` the smoothing method is chosen based on the
+#'   For `method = NULL` the smoothing method is chosen based on the
 #'   size of the largest group (across all panels). [loess()] is
 #'   used for less than 1,000 observations; otherwise [mgcv::gam()] is
 #'   used with `formula = y ~ s(x, bs = "cs")`. Somewhat anecdotally,
@@ -10,11 +12,11 @@
 #'   so does not work for larger datasets.
 #'
 #'   If you have fewer than 1,000 observations but want to use the same `gam()`
-#'   model that `method = "auto"` would use, then set
+#'   model that `method = NULL` would use, then set
 #'   `method = "gam", formula = y ~ s(x, bs = "cs")`.
 #' @param formula Formula to use in smoothing function, eg. `y ~ x`,
 #'   `y ~ poly(x, 2)`, `y ~ log(x)`. `NULL` by default, in which case
-#'   `method = "auto"` implies `formula = y ~ x` when there are fewer than 1,000
+#'   `method = NULL` implies `formula = y ~ x` when there are fewer than 1,000
 #'   observations and `formula = y ~ s(x, bs = "cs")` otherwise.
 #' @param se Display confidence interval around smooth? (`TRUE` by default, see
 #'   `level` to control.)
@@ -39,7 +41,7 @@
 stat_smooth <- function(mapping = NULL, data = NULL,
                         geom = "smooth", position = "identity",
                         ...,
-                        method = "auto",
+                        method = NULL,
                         formula = NULL,
                         se = TRUE,
                         n = 80,
@@ -59,7 +61,7 @@ stat_smooth <- function(mapping = NULL, data = NULL,
     show.legend = show.legend,
     inherit.aes = inherit.aes,
     params = list(
-      method = method,
+      method = if (!is.null(method) && identical(method, "auto")) NULL else method,
       formula = formula,
       se = se,
       n = n,
@@ -80,7 +82,8 @@ stat_smooth <- function(mapping = NULL, data = NULL,
 StatSmooth <- ggproto("StatSmooth", Stat,
 
   setup_params = function(data, params) {
-    if (identical(params$method, "auto")) {
+    msg <- NULL
+    if (is.null(params$method)) {
       # Use loess for small datasets, gam with a cubic regression basis for
       # larger. Based on size of the _largest_ group to avoid bad memory
       # behaviour of loess
@@ -91,20 +94,35 @@ StatSmooth <- ggproto("StatSmooth", Stat,
       } else {
         params$method <- "gam"
       }
-      message("`geom_smooth()` using method = '", params$method,
-              "' and formula '", deparse(params$formula), "'")
+
+      msg <- paste0("`geom_smooth()` using method = '", params$method, "'")
+    }
+
+    if (is.null(params$formula)) {
+      params$formula <- if (identical(params$method, "gam")) {
+        y ~ s(x, bs = "cs")
+      } else {
+        y ~ x
+      }
+      msg <- if (is.null(msg)) {
+        msg <- paste0("`geom_smooth()` using formula = '", deparse(params$formula), "'")
+      } else {
+        msg <- paste0(msg, " and formula '", deparse(params$formula), "'")
+      }
     }
+
     if (identical(params$method, "gam")) {
       params$method <- mgcv::gam
-      params$formula <- params$formula %||% (y ~ s(x, bs = "cs"))
-    } else {
-      params$formula <- params$formula %||% (y ~ x)
+    }
+
+    if (!is.null(msg)) {
+      message(msg)
     }
 
     params
   },
 
-  compute_group = function(data, scales, method = "auto", formula = NULL,
+  compute_group = function(data, scales, method = NULL, formula = NULL,
                            se = TRUE, n = 80, span = 0.75, fullrange = FALSE,
                            xseq = NULL, level = 0.95, method.args = list(),
                            na.rm = FALSE) {
diff --git a/man/geom_smooth.Rd b/man/geom_smooth.Rd
index 3e3e54c45d..ad06fc5256 100644
--- a/man/geom_smooth.Rd
+++ b/man/geom_smooth.Rd
@@ -6,11 +6,11 @@
 \title{Smoothed conditional means}
 \usage{
 geom_smooth(mapping = NULL, data = NULL, stat = "smooth",
-  position = "identity", ..., method = "auto", formula = NULL,
+  position = "identity", ..., method = NULL, formula = NULL,
   se = TRUE, na.rm = FALSE, show.legend = NA, inherit.aes = TRUE)
 
 stat_smooth(mapping = NULL, data = NULL, geom = "smooth",
-  position = "identity", ..., method = "auto", formula = NULL,
+  position = "identity", ..., method = NULL, formula = NULL,
   se = TRUE, n = 80, span = 0.75, fullrange = FALSE,
   level = 0.95, method.args = list(), na.rm = FALSE,
   show.legend = NA, inherit.aes = TRUE)
@@ -44,11 +44,13 @@ often aesthetics, used to set an aesthetic to a fixed value, like
 \code{colour = "red"} or \code{size = 3}. They may also be parameters
 to the paired geom/stat.}
 
-\item{method}{Smoothing method (function) to use, accepts either a character vector,
-e.g. \code{"auto"}, \code{"lm"}, \code{"glm"}, \code{"gam"}, \code{"loess"} or a function, e.g.
-\code{MASS::rlm} or \code{mgcv::gam}, \code{base::lm}, or \code{base::loess}.
+\item{method}{Smoothing method (function) to use, accepts either
+\code{NULL} or a character vector, e.g. \code{"lm"}, \code{"glm"}, \code{"gam"}, \code{"loess"}
+or a function, e.g. \code{MASS::rlm} or \code{mgcv::gam}, \code{stats::lm}, or \code{stats::loess}.
+\code{"auto"} is also accepted for backwards compatibility.  It is equivalent to
+\code{NULL}.
 
-For \code{method = "auto"} the smoothing method is chosen based on the
+For \code{method = NULL} the smoothing method is chosen based on the
 size of the largest group (across all panels). \code{\link[=loess]{loess()}} is
 used for less than 1,000 observations; otherwise \code{\link[mgcv:gam]{mgcv::gam()}} is
 used with \code{formula = y ~ s(x, bs = "cs")}. Somewhat anecdotally,
@@ -56,12 +58,12 @@ used with \code{formula = y ~ s(x, bs = "cs")}. Somewhat anecdotally,
 so does not work for larger datasets.
 
 If you have fewer than 1,000 observations but want to use the same \code{gam()}
-model that \code{method = "auto"} would use, then set
+model that \code{method = NULL} would use, then set
 \code{method = "gam", formula = y ~ s(x, bs = "cs")}.}
 
 \item{formula}{Formula to use in smoothing function, eg. \code{y ~ x},
 \code{y ~ poly(x, 2)}, \code{y ~ log(x)}. \code{NULL} by default, in which case
-\code{method = "auto"} implies \code{formula = y ~ x} when there are fewer than 1,000
+\code{method = NULL} implies \code{formula = y ~ x} when there are fewer than 1,000
 observations and \code{formula = y ~ s(x, bs = "cs")} otherwise.}
 
 \item{se}{Display confidence interval around smooth? (\code{TRUE} by default, see

From 5910606e566ec4d872033af79a7c59de36c07771 Mon Sep 17 00:00:00 2001
From: Bernie Gray <bfgray3@gmail.com>
Date: Thu, 13 Jun 2019 23:24:04 -0400
Subject: [PATCH 08/12] tweak formula message for geom_smooth

---
 R/stat-smooth.r | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/R/stat-smooth.r b/R/stat-smooth.r
index 211acde24a..669aca42fc 100644
--- a/R/stat-smooth.r
+++ b/R/stat-smooth.r
@@ -105,7 +105,7 @@ StatSmooth <- ggproto("StatSmooth", Stat,
         y ~ x
       }
       msg <- if (is.null(msg)) {
-        msg <- paste0("`geom_smooth()` using formula = '", deparse(params$formula), "'")
+        msg <- paste0("`geom_smooth()` using formula '", deparse(params$formula), "'")
       } else {
         msg <- paste0(msg, " and formula '", deparse(params$formula), "'")
       }

From 99e9ad2481c01d583a3cd6b51e05b797489891af Mon Sep 17 00:00:00 2001
From: Bernie Gray <bfgray3@gmail.com>
Date: Sat, 15 Jun 2019 21:37:25 -0400
Subject: [PATCH 09/12] clean up smoothing message

---
 R/geom-smooth.r |  2 +-
 R/stat-smooth.r | 14 +++++---------
 2 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/R/geom-smooth.r b/R/geom-smooth.r
index da992e8305..a4e224450f 100644
--- a/R/geom-smooth.r
+++ b/R/geom-smooth.r
@@ -91,7 +91,7 @@ geom_smooth <- function(mapping = NULL, data = NULL,
     ...
   )
   if (identical(stat, "smooth")) {
-    params$method <- if (!is.null(method) && identical(method, "auto")) NULL else method
+    params$method <- method
     params$formula <- formula
   }
 
diff --git a/R/stat-smooth.r b/R/stat-smooth.r
index 669aca42fc..00e0101525 100644
--- a/R/stat-smooth.r
+++ b/R/stat-smooth.r
@@ -82,7 +82,7 @@ stat_smooth <- function(mapping = NULL, data = NULL,
 StatSmooth <- ggproto("StatSmooth", Stat,
 
   setup_params = function(data, params) {
-    msg <- NULL
+    msg <- character()
     if (is.null(params$method)) {
       # Use loess for small datasets, gam with a cubic regression basis for
       # larger. Based on size of the _largest_ group to avoid bad memory
@@ -95,7 +95,7 @@ StatSmooth <- ggproto("StatSmooth", Stat,
         params$method <- "gam"
       }
 
-      msg <- paste0("`geom_smooth()` using method = '", params$method, "'")
+      msg <- c(msg, paste0("method = '", params$method, "'"))
     }
 
     if (is.null(params$formula)) {
@@ -104,19 +104,15 @@ StatSmooth <- ggproto("StatSmooth", Stat,
       } else {
         y ~ x
       }
-      msg <- if (is.null(msg)) {
-        msg <- paste0("`geom_smooth()` using formula '", deparse(params$formula), "'")
-      } else {
-        msg <- paste0(msg, " and formula '", deparse(params$formula), "'")
-      }
+      msg <- c(msg, paste0("formula '", deparse(params$formula), "'"))
     }
 
     if (identical(params$method, "gam")) {
       params$method <- mgcv::gam
     }
 
-    if (!is.null(msg)) {
-      message(msg)
+    if (length(msg) > 0) {
+      message("`geom_smooth()` using ", paste0(msg, collapse = " and "))
     }
 
     params

From b4d92e71f1d6f1cde7cff28e1557343c419fc9cc Mon Sep 17 00:00:00 2001
From: Bernie Gray <bfgray3@gmail.com>
Date: Sat, 15 Jun 2019 22:01:28 -0400
Subject: [PATCH 10/12] fix backwards compatibility of method = 'auto'

---
 R/stat-smooth.r                   | 4 ++--
 tests/testthat/test-geom-smooth.R | 9 +++++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/R/stat-smooth.r b/R/stat-smooth.r
index 579f26dd4c..02b29c23d6 100644
--- a/R/stat-smooth.r
+++ b/R/stat-smooth.r
@@ -61,7 +61,7 @@ stat_smooth <- function(mapping = NULL, data = NULL,
     show.legend = show.legend,
     inherit.aes = inherit.aes,
     params = list(
-      method = if (!is.null(method) && identical(method, "auto")) NULL else method,
+      method = method,
       formula = formula,
       se = se,
       n = n,
@@ -83,7 +83,7 @@ StatSmooth <- ggproto("StatSmooth", Stat,
 
   setup_params = function(data, params) {
     msg <- character()
-    if (is.null(params$method)) {
+    if (is.null(params$method) || identical(params$method, "auto")) {
       # Use loess for small datasets, gam with a cubic regression basis for
       # larger. Based on size of the _largest_ group to avoid bad memory
       # behaviour of loess
diff --git a/tests/testthat/test-geom-smooth.R b/tests/testthat/test-geom-smooth.R
index f7bce014f9..e3113d4ebe 100644
--- a/tests/testthat/test-geom-smooth.R
+++ b/tests/testthat/test-geom-smooth.R
@@ -48,6 +48,15 @@ test_that("default smoothing methods for small and large data sets work", {
     "method = 'gam' and formula 'y ~ s\\(x, bs = \"cs\"\\)"
   )
   expect_equal(plot_data$y, as.numeric(out))
+
+  # backwards compatibility of method = "auto"
+  p <- ggplot(df, aes(x, y)) + geom_smooth(method = "auto")
+
+  expect_message(
+    plot_data <- layer_data(p),
+    "method = 'gam' and formula 'y ~ s\\(x, bs = \"cs\"\\)"
+  )
+  expect_equal(plot_data$y, as.numeric(out))
 })
 
 

From 3aaa53ebfeb890b7192fe9a9b2da410b552ffc8d Mon Sep 17 00:00:00 2001
From: Bernie Gray <bfgray3@gmail.com>
Date: Sat, 15 Jun 2019 22:03:45 -0400
Subject: [PATCH 11/12] code aesthetics

---
 R/stat-smooth.r | 2 --
 1 file changed, 2 deletions(-)

diff --git a/R/stat-smooth.r b/R/stat-smooth.r
index 02b29c23d6..ddf27e72ec 100644
--- a/R/stat-smooth.r
+++ b/R/stat-smooth.r
@@ -94,7 +94,6 @@ StatSmooth <- ggproto("StatSmooth", Stat,
       } else {
         params$method <- "gam"
       }
-
       msg <- c(msg, paste0("method = '", params$method, "'"))
     }
 
@@ -106,7 +105,6 @@ StatSmooth <- ggproto("StatSmooth", Stat,
       }
       msg <- c(msg, paste0("formula '", deparse(params$formula), "'"))
     }
-
     if (identical(params$method, "gam")) {
       params$method <- mgcv::gam
     }

From ca5ba90656ed276dd2efac1cd260c1c8b84bda36 Mon Sep 17 00:00:00 2001
From: Thomas Lin Pedersen <thomasp85@gmail.com>
Date: Mon, 30 Sep 2019 11:53:43 +0200
Subject: [PATCH 12/12] Fix styling

---
 R/stat-smooth.r | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/R/stat-smooth.r b/R/stat-smooth.r
index ddf27e72ec..0bf34984c0 100644
--- a/R/stat-smooth.r
+++ b/R/stat-smooth.r
@@ -98,10 +98,10 @@ StatSmooth <- ggproto("StatSmooth", Stat,
     }
 
     if (is.null(params$formula)) {
-      params$formula <- if (identical(params$method, "gam")) {
-        y ~ s(x, bs = "cs")
+      if (identical(params$method, "gam")) {
+        params$formula <- y ~ s(x, bs = "cs")
       } else {
-        y ~ x
+        params$formula <- y ~ x
       }
       msg <- c(msg, paste0("formula '", deparse(params$formula), "'"))
     }