From 62881a71840faadb3d5cc7d0859c2f2c8bfdd323 Mon Sep 17 00:00:00 2001
From: "Jonathan M. Waldrop" <relik107@gmail.com>
Date: Fri, 15 May 2026 14:17:50 -0500
Subject: [PATCH] More detailed error messages for Module::change_input and
 Module::change_submod

---
 include/pluginplay/module/module_class.hpp       |  8 ++++++++
 .../module_manager/module_manager_class.hpp      |  8 +++++++-
 src/pluginplay/module/module.cpp                 |  8 ++++++++
 tests/cxx/unit_tests/pluginplay/catch.hpp        |  1 +
 .../pluginplay/module/module_class.cpp           | 16 +++++++++++++---
 5 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/include/pluginplay/module/module_class.hpp b/include/pluginplay/module/module_class.hpp
index f6dc01637..37494d18b 100644
--- a/include/pluginplay/module/module_class.hpp
+++ b/include/pluginplay/module/module_class.hpp
@@ -747,6 +747,14 @@ bool Module::ready() const {
 template<typename T>
 void Module::change_input(const type::key& key, T&& value) {
     assert_not_locked_();
+    if(!inputs().count(key)) {
+        std::string msg = " does not have input \"" + key + "\"";
+        if(has_name())
+            msg = "Module \"" + get_name() + "\"" + msg;
+        else
+            msg = "Unnamed module" + msg;
+        throw std::out_of_range(msg);
+    }
     get_input_(key).change(std::forward<T>(value));
 }
 
diff --git a/include/pluginplay/module_manager/module_manager_class.hpp b/include/pluginplay/module_manager/module_manager_class.hpp
index 3249514f4..7ba2befb7 100644
--- a/include/pluginplay/module_manager/module_manager_class.hpp
+++ b/include/pluginplay/module_manager/module_manager_class.hpp
@@ -100,6 +100,13 @@ class ModuleManager {
      */
     type::size size() const noexcept;
 
+    /** @brief Used to add a new module to the list
+     *
+     * @tparam ModuleType The type of the module being added. This type must be
+     *                    constructible with no arguments and must inherit from
+     *                    ModuleBase.
+     * @param module_key
+     */
     template<typename ModuleType>
     void add_module(type::key module_key);
 
@@ -108,7 +115,6 @@ class ModuleManager {
      * @param module_key
      * @param base
      */
-
     void add_module(type::key module_key, module_base_ptr base);
 
     ///@{
diff --git a/src/pluginplay/module/module.cpp b/src/pluginplay/module/module.cpp
index f5090342d..574cc1711 100644
--- a/src/pluginplay/module/module.cpp
+++ b/src/pluginplay/module/module.cpp
@@ -78,6 +78,14 @@ void Module::lock() { m_pimpl_->lock(); }
 
 void Module::change_submod(type::key key, std::shared_ptr<Module> new_module) {
     assert_not_locked_();
+    if(!submods().count(key)) {
+        std::string msg = " does not have submodule \"" + key + "\"";
+        if(has_name())
+            msg = "Module \"" + get_name() + "\"" + msg;
+        else
+            msg = "Unnamed module" + msg;
+        throw std::out_of_range(msg);
+    }
     m_pimpl_->submods().at(key).change(new_module);
 }
 
diff --git a/tests/cxx/unit_tests/pluginplay/catch.hpp b/tests/cxx/unit_tests/pluginplay/catch.hpp
index 42e8ef612..5f95d58cd 100644
--- a/tests/cxx/unit_tests/pluginplay/catch.hpp
+++ b/tests/cxx/unit_tests/pluginplay/catch.hpp
@@ -18,3 +18,4 @@
 #include <catch2/catch_approx.hpp>
 #include <catch2/catch_template_test_macros.hpp>
 #include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers_exception.hpp>
diff --git a/tests/cxx/unit_tests/pluginplay/module/module_class.cpp b/tests/cxx/unit_tests/pluginplay/module/module_class.cpp
index fd0749c95..4e9e12fe4 100644
--- a/tests/cxx/unit_tests/pluginplay/module/module_class.cpp
+++ b/tests/cxx/unit_tests/pluginplay/module/module_class.cpp
@@ -290,7 +290,12 @@ TEST_CASE("Module : change_input") {
     }
     SECTION("Throws if input does not exist") {
         auto mod = make_module<NotReadyModule>();
-        REQUIRE_THROWS_AS(mod->change_input("Not a key", 3), std::out_of_range);
+        REQUIRE_THROWS_WITH(mod->change_input("Not a key", 3),
+                            "Unnamed module does not have input \"Not a key\"");
+        mod->set_name("Test");
+        REQUIRE_THROWS_WITH(
+          mod->change_input("Not a key", 3),
+          "Module \"Test\" does not have input \"Not a key\"");
     }
     SECTION("Throws if value is wrong type") {
         auto mod = make_module<NotReadyModule>();
@@ -316,8 +321,13 @@ TEST_CASE("Module : change_submod") {
         REQUIRE_THROWS_AS(p.change_submod(key, value), std::runtime_error);
     }
     SECTION("Throws if request does not exist") {
-        REQUIRE_THROWS_AS(mod->change_submod("Not a key", value),
-                          std::out_of_range);
+        REQUIRE_THROWS_WITH(
+          mod->change_submod("Not a key", value),
+          "Unnamed module does not have submodule \"Not a key\"");
+        mod->set_name("Test");
+        REQUIRE_THROWS_WITH(
+          mod->change_submod("Not a key", value),
+          "Module \"Test\" does not have submodule \"Not a key\"");
     }
     SECTION("Throws if value is wrong type") {
         auto mod2 = make_module<NotReadyModule>();