From 630ab47cff290e94380e0bfa57d6de964c722af3 Mon Sep 17 00:00:00 2001
From: Hadley Wickham <h.wickham@gmail.com>
Date: Thu, 28 Apr 2022 13:02:24 -0500
Subject: [PATCH] Handle case where param matches more than once

---
 R/rd-inherit.R                   |  5 ++++-
 tests/testthat/test-rd-inherit.R | 23 ++++++++++++++++++++++-
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/R/rd-inherit.R b/R/rd-inherit.R
index 0802b343..61141685 100644
--- a/R/rd-inherit.R
+++ b/R/rd-inherit.R
@@ -176,7 +176,10 @@ match_param <- function(from, to) {
     return(NULL)
   }
 
-  unique(c(to, to)[match(from, to_std)])
+  union(
+    setdiff(to[match(from, to)], NA),
+    setdiff(to[match(from, flip_dot(to))], NA)
+  )
 }
 
 inherit_dot_params <- function(topic, topics, env) {
diff --git a/tests/testthat/test-rd-inherit.R b/tests/testthat/test-rd-inherit.R
index f7afe85c..eda8203a 100644
--- a/tests/testthat/test-rd-inherit.R
+++ b/tests/testthat/test-rd-inherit.R
@@ -290,6 +290,7 @@ test_that("match_params can ignore . prefix", {
   expect_equal(match_param(c(".x", "y"), c(".x", ".y", ".z")), c(".x", ".y"))
   expect_equal(match_param(c(".x", "x"), c("x", ".x")), c(".x", "x"))
   expect_equal(match_param(c(".x", "x"), "x"), "x")
+  expect_equal(match_param("x", c(".x", "x")), c("x", ".x"))
 })
 
 test_that("multiple @inheritParam tags gathers all params", {
@@ -299,7 +300,6 @@ test_that("multiple @inheritParam tags gathers all params", {
     #' @param x X
     a <- function(x) {}
 
-
     #' B
     #'
     #' @param y Y
@@ -354,6 +354,27 @@ test_that("@inheritParam preserves mixed names", {
   expect_equal(out$get_value("param"), c(".x,x" = "X"))
 })
 
+test_that("can inherit from same arg twice", {
+  out <- roc_proc_text(rd_roclet(), "
+    #' A.
+    #'
+    #' @param x X
+    a <- function(x) {}
+
+    #' B
+    #'
+    #' @inheritParams a
+    b <- function(x) {}
+
+    #' C
+    #'
+    #' @inheritParams a
+    #' @rdname b
+    c <- function(.x) {}
+    ")[[2]]
+  expect_equal(out$get_value("param"), c("x,.x" = "X"))
+})
+
 test_that("@inheritParams can inherit from inherited params", {
   out <- roc_proc_text(rd_roclet(), "
     #' C