From dd713e70676984843067e7917c7629576fa80f73 Mon Sep 17 00:00:00 2001
From: Hadley Wickham <h.wickham@gmail.com>
Date: Mon, 11 Jul 2022 07:42:11 +1200
Subject: [PATCH] Don't list inherited methods if there aren't any (#1387)

Fixes #1371
---
 NEWS.md                        |  3 +++
 R/rd-r6.R                      |  4 +++-
 tests/testthat/_snaps/rd-r6.md | 26 ++++++++++++++++++++++++++
 tests/testthat/test-rd-r6.R    | 27 +++++++++++++++++++++++++++
 4 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/NEWS.md b/NEWS.md
index 49105c88..2986b2e8 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,8 @@
 # roxygen2 (development version)
 
+* R6 documentation no longer shows inherited methods if there aren't any 
+  (#1371).
+
 * If you have a daily build of RStudio, the lists of changed Rd files are
   now clickable so you can immediately see the rendered development
   documentation (#1354).
diff --git a/R/rd-r6.R b/R/rd-r6.R
index 2cb5bdd0..a70c8552 100644
--- a/R/rd-r6.R
+++ b/R/rd-r6.R
@@ -258,9 +258,11 @@ r6_inherited_method_list <- function(block, r6data) {
   self <- r6data$self
   super_meth <- super_meth[! super_meth$name %in% self$name, ]
   super_meth <- super_meth[! duplicated(super_meth$name), ]
+  if (nrow(super_meth) == 0) {
+    return()
+  }
 
   super_meth <- super_meth[rev(seq_len(nrow(super_meth))), ]
-
   details <- paste0(
     "<details",
     if (nrow(super_meth) <= 5) " open",
diff --git a/tests/testthat/_snaps/rd-r6.md b/tests/testthat/_snaps/rd-r6.md
index 7597e9da..b395e59f 100644
--- a/tests/testthat/_snaps/rd-r6.md
+++ b/tests/testthat/_snaps/rd-r6.md
@@ -14,6 +14,32 @@
       Warning:
       [<text>:10] @description Cannot find matching R6 method
 
+# class with no inherited methods
+
+    Code
+      cat(format(rd$get_section("rawRd")))
+    Output
+      \section{Super class}{
+      \code{\link[R_GlobalEnv:C1]{R_GlobalEnv::C1}} -> \code{C2}
+      }
+      \section{Methods}{
+      \subsection{Public methods}{
+      \itemize{
+      \item \href{#method-C2-meth1}{\code{C2$meth1()}}
+      }
+      }
+      \if{html}{\out{<hr>}}
+      \if{html}{\out{<a id="method-C2-meth1"></a>}}
+      \if{latex}{\out{\hypertarget{method-C2-meth1}{}}}
+      \subsection{Method \code{meth1()}}{
+      method1
+      \subsection{Usage}{
+      \if{html}{\out{<div class="r">}}\preformatted{C2$meth1()}\if{html}{\out{</div>}}
+      }
+      
+      }
+      }
+
 # integration test
 
     Code
diff --git a/tests/testthat/test-rd-r6.R b/tests/testthat/test-rd-r6.R
index 66941a06..05d382cd 100644
--- a/tests/testthat/test-rd-r6.R
+++ b/tests/testthat/test-rd-r6.R
@@ -296,6 +296,33 @@ test_that("warning if no method comes after the docs", {
   doc <- format(rd)
 })
 
+test_that("class with no inherited methods", {
+  text <- "
+    C1 <- R6::R6Class('C1', cloneable = FALSE)
+
+    #' @title Title
+    #' @description Description.
+    #' @details Details.
+    C2 <- R6::R6Class('C2',
+      inherit = C1,
+      cloneable = FALSE,
+      public = list(
+        #' @description method1
+        meth1 = function() 1
+      )
+    )"
+
+  env <- new.env(parent = globalenv())
+
+  eval(parse(text = text, keep.source = TRUE), envir = env)
+  block <- parse_text(text, env = env)[[1]]
+  rd <- RoxyTopic$new()
+
+  topic_add_r6_methods(rd, block, env)
+  expect_snapshot(cat(format(rd$get_section("rawRd"))))
+})
+
+
 test_that("integration test", {
 
   wd <- getwd()