From 8af47e998576b6de4b333a3d9e20155d161b86d0 Mon Sep 17 00:00:00 2001
From: YuviPanda <yuvipanda@gmail.com>
Date: Thu, 23 Jun 2022 12:34:48 -0700
Subject: [PATCH] Add comment about how r_version is determined

---
 repo2docker/buildpacks/r.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/repo2docker/buildpacks/r.py b/repo2docker/buildpacks/r.py
index 7127c8ea..ec973f9e 100644
--- a/repo2docker/buildpacks/r.py
+++ b/repo2docker/buildpacks/r.py
@@ -79,6 +79,8 @@ class RBuildPack(PythonBuildPack):
 
         if not hasattr(self, "_r_version"):
             parts = self.runtime.split("-")
+            # If runtime.txt is not set, or if it isn't of the form r-<version>-<yyyy>-<mm>-<dd>,
+            # we don't use any of it in determining r version and just use the default
             if len(parts) == 5:
                 r_version = parts[1]
                 # For versions of form x.y, we want to explicitly provide x.y.z - latest patchlevel