From b5dbb5c65dbb59dbe9c4883b33410f1c1bab92b5 Mon Sep 17 00:00:00 2001
From: Copilot <223556219+Copilot@users.noreply.github.com>
Date: Sun, 31 May 2026 20:16:57 -0700
Subject: [PATCH] Pin the host module instead of wrapping a borrowed HMODULE

PluginSystem::Load stored the result of GetModuleHandleA(nullptr) in
a wil::unique_hmodule for the .exe path. GetModuleHandle returns a
borrowed handle that, per the Microsoft docs, must not be passed to
FreeLibrary. wil::unique_hmodule calls FreeLibrary on destruction,
so the loader refcount on the host module was being decremented in
two paths every startup: the immediate destruct when the host did
not export Supports, and the eventual unload through
PluginBase::m_module when the host was accepted as a plugin.

Acquire a real reference with GetModuleHandleExW(
GET_MODULE_HANDLE_EX_FLAG_PIN, ...) instead. Pinning makes the
eventual FreeLibrary a documented no-op, the loader bookkeeping
stays balanced, and the existing RAII model in PluginBase does not
have to change.

Fixes #142

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 src/dll/Systems/PluginSystem.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/dll/Systems/PluginSystem.cpp b/src/dll/Systems/PluginSystem.cpp
index 8e6f2b1a..685668fa 100644
--- a/src/dll/Systems/PluginSystem.cpp
+++ b/src/dll/Systems/PluginSystem.cpp
@@ -235,7 +235,16 @@ void PluginSystem::Load(const std::filesystem::path& aPath, bool aUseAlteredSear
 
     wil::unique_hmodule handle;
     if (aPath.extension() == L".exe")
-        handle.reset(GetModuleHandleA(nullptr));
+    {
+        // GetModuleHandle returns a borrowed handle that must not be passed to FreeLibrary, but
+        // PluginBase stores the handle in another wil::unique_hmodule. Pin the host module so the
+        // eventual FreeLibrary call is a documented no-op and the loader refcount stays balanced.
+        HMODULE raw = nullptr;
+        if (GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_PIN, nullptr, &raw))
+        {
+            handle.reset(raw);
+        }
+    }
     else
         handle.reset(LoadLibraryEx(aPath.c_str(), nullptr, flags));