From dd3fa631ddbec82a4ab11ec6948b9f4d20490540 Mon Sep 17 00:00:00 2001
From: Min RK <benjaminrk@gmail.com>
Date: Mon, 14 Sep 2020 11:55:52 +0200
Subject: [PATCH] support R 4

---
 repo2docker/buildpacks/r.py | 12 +++++++++---
 tests/r/r4/install.R        |  1 +
 tests/r/r4/runtime.txt      |  1 +
 tests/r/r4/verify           |  7 +++++++
 4 files changed, 18 insertions(+), 3 deletions(-)
 create mode 100644 tests/r/r4/install.R
 create mode 100644 tests/r/r4/runtime.txt
 create mode 100755 tests/r/r4/verify

diff --git a/repo2docker/buildpacks/r.py b/repo2docker/buildpacks/r.py
index 0173a1e4..d3f9c07e 100644
--- a/repo2docker/buildpacks/r.py
+++ b/repo2docker/buildpacks/r.py
@@ -78,6 +78,8 @@ class RBuildPack(PythonBuildPack):
             "3.6": "3.6.1-3bionic",
             "3.6.0": "3.6.0-2bionic",
             "3.6.1": "3.6.1-3bionic",
+            "4.0": "4.0.2-1.1804.0",
+            "4.0.2": "4.0.2-1.1804.0",
         }
         # the default if nothing is specified
         r_version = "3.6"
@@ -238,13 +240,17 @@ class RBuildPack(PythonBuildPack):
 
         scripts = []
         # For R 3.4 we want to use the default Ubuntu package but otherwise
-        # we use the packages from a PPA
+        # we use the packages from R's own repo
         if V(self.r_version) >= V("3.5"):
+            if V(self.r_version) >= V("4"):
+                vs = "40"
+            else:
+                vs = "35"
             scripts += [
                 (
                     "root",
-                    r"""
-                    echo "deb https://cloud.r-project.org/bin/linux/ubuntu bionic-cran35/" > /etc/apt/sources.list.d/r3.6-ubuntu.list
+                    rf"""
+                    echo "deb https://cloud.r-project.org/bin/linux/ubuntu bionic-cran{vs}/" > /etc/apt/sources.list.d/r-ubuntu.list
                     """,
                 ),
                 # Use port 80 to talk to the keyserver to increase the chances
diff --git a/tests/r/r4/install.R b/tests/r/r4/install.R
new file mode 100644
index 00000000..df6d6a83
--- /dev/null
+++ b/tests/r/r4/install.R
@@ -0,0 +1 @@
+install.packages("ggplot2")
diff --git a/tests/r/r4/runtime.txt b/tests/r/r4/runtime.txt
new file mode 100644
index 00000000..e0b26306
--- /dev/null
+++ b/tests/r/r4/runtime.txt
@@ -0,0 +1 @@
+r-4.0-2020-07-07
diff --git a/tests/r/r4/verify b/tests/r/r4/verify
new file mode 100755
index 00000000..6d28082b
--- /dev/null
+++ b/tests/r/r4/verify
@@ -0,0 +1,7 @@
+#!/usr/bin/env Rscript
+library('ggplot2')
+
+print(version)
+if (version$major != "4") {
+  quit("yes", 1)
+}