From f92de8b72baff237f7112ab51d6dc535b2389136 Mon Sep 17 00:00:00 2001
From: Zhenglei Gao <zhenglei.gao@baer.com>
Date: Tue, 4 Aug 2026 10:52:58 +0200
Subject: [PATCH] Fix mdist() lookup to ssdtools namespace only (#479).

Attached packages exporting m* helpers (notably actuar) no longer break ssd_fit_dists(); add regression tests including actuar attached and search-path clashes.

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 R/pqr.R                     | 11 ++++--
 tests/testthat/test-mdist.R | 72 +++++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+), 2 deletions(-)
 create mode 100644 tests/testthat/test-mdist.R

diff --git a/R/pqr.R b/R/pqr.R
index 6fa9d7ed..49283e55 100644
--- a/R/pqr.R
+++ b/R/pqr.R
@@ -229,8 +229,15 @@ bdist <- function(dist, data, min_pmix, range_shape1, range_shape2) {
 }
 
 mdist <- function(dist) {
-  fun <- paste0("m", dist)
-  if (!exists(fun, mode = "function")) {
+  # Scope to ssdtools only — attached packages (e.g. actuar::mlnorm) must not
+  # satisfy this hook (#479).
+  fun <- get0(
+    paste0("m", dist),
+    envir = asNamespace("ssdtools"),
+    mode = "function",
+    inherits = FALSE
+  )
+  if (is.null(fun)) {
     return(list())
   }
   do.call(fun, args = list())
diff --git a/tests/testthat/test-mdist.R b/tests/testthat/test-mdist.R
new file mode 100644
index 00000000..04f1d8e7
--- /dev/null
+++ b/tests/testthat/test-mdist.R
@@ -0,0 +1,72 @@
+# Copyright 2015-2023 Province of British Columbia
+# Copyright 2021 Environment and Climate Change Canada
+# Copyright 2023-2024 Australian Government Department of Climate Change,
+# Energy, the Environment and Water
+#
+#    Licensed under the Apache License, Version 2.0 (the "License");
+#    you may not use this file except in compliance with the License.
+#    You may obtain a copy of the License at
+#
+#       https://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+
+test_that("mdist returns empty list when no package map exists", {
+  expect_identical(ssdtools:::mdist("lnorm"), list())
+})
+
+test_that("mdist finds package map functions in the ssdtools namespace", {
+  expect_identical(
+    ssdtools:::mdist("invpareto"),
+    list(log_scale = factor(NA))
+  )
+})
+
+test_that("mdist ignores conflicting m* functions on the search path (#479)", {
+  # Simulate actuar::mlnorm(order, ...) without requiring actuar.
+  assign(
+    "mlnorm",
+    function(order, meanlog = 0, sdlog = 1) {
+      stop("search-path mlnorm should not be called", call. = FALSE)
+    },
+    envir = .GlobalEnv
+  )
+  withr::defer(rm("mlnorm", envir = .GlobalEnv))
+
+  expect_identical(ssdtools:::mdist("lnorm"), list())
+  expect_no_error(
+    ssd_fit_dists(ssddata::ccme_boron, dists = c("lnorm", "gamma"))
+  )
+})
+
+test_that("ssd_fit_dists works with actuar attached (#479)", {
+  skip_if_not_installed("actuar")
+  withr::local_package("actuar")
+
+  expect_no_error(
+    fit <- ssd_fit_dists(
+      ssddata::ccme_boron,
+      dists = c("lnorm", "llogis", "gamma", "weibull")
+    )
+  )
+  expect_s3_class(fit, "fitdists")
+  expect_identical(names(fit), c("lnorm", "llogis", "gamma", "weibull"))
+})
+
+test_that("ssd_fit_dists censored data works with actuar attached (#479)", {
+  skip_if_not_installed("actuar")
+  withr::local_package("actuar")
+
+  data <- data.frame(
+    left = c(1, 2, 3, 4, 5, 6),
+    right = c(1, 2, Inf, 4, Inf, 6)
+  )
+  expect_no_error(
+    fit <- ssd_fit_dists(data, left = "left", right = "right", dists = "lnorm")
+  )
+  expect_s3_class(fit, "fitdists")
+})