bug: frontend: Safe Mode and --only-bundled-plugins always show the "Plugin Errors" dialog, and removing a Missing plugin in the Plugin Manager changes the wrong plugin (upstream #13948, #14005) #1079

Two upstream OBS bugs in the Plugin Manager, both reported by FiniteSingularity: obsproject/obs-studio#13948 (Safe Mode lists third-party plugins as Missing) and obsproject/obs-studio#14005 (the trash button for a Missing plugin doesn't always remove it). Warchamp7 fixed them upstream in obsproject/obs-studio#14001 and obsproject/obs-studio#14008, both merged on 2026-10-08. Neither fix is in obs-rust yet. One issue for both because #14008 builds on #14001 and they touch the same three files.

Location

1. frontend/plugin-manager/PluginManager.cpp loadAllPlugins() (line 96) only sets loadState_ inside if (loadMode_ == Mode::Full). Safe Mode and --only-bundled-plugins load with Mode::CoreOnly (frontend/OBSApp.cpp line 1963), so loadState_ keeps its default State::Failure (PluginManager.hpp line 53). OBSApp::handlePluginLoadState() (OBSApp.cpp line 1969) then opens the modal "Plugin Errors" box (handlePluginFailure(), exec()) after the main window loads, on every such start.
2. frontend/plugin-manager/PluginManagerWindow.cpp setupInstalledPage() (line 135): a cached plugin that is not loaded is Status::Missing. In both modes that is every third-party plugin. Each such row gets a trash button that deletes the plugin's saved entry (enabled state and the types it provides).
3. Same file, line 164: each row's Entry keeps &metadata, a pointer into the window's modules_ vector. The trash handler (line 207) looks its entry up by address and calls modules_.erase(), which shifts every later element down one slot. After that, each later row points at the next plugin: its trash button removes the wrong entry, and its toggle (InstalledPluginRow.cpp line 135, metadata->enabled = checked) turns a different plugin on or off. PluginManager::open() saves the result to plugin_manager/modules.json when the window is saved.

Class

Logic error (a state that is never set) and use of invalidated pointers. The modal dialog blocks unattended starts, and the Plugin Manager can delete or disable the wrong plugin's settings. No crash was seen.

How it is reached

• --safe-mode, Help > Restart in Safe Mode, the crash dialog's "Launch in Safe Mode", or --only-bundled-plugins: the "Plugin Errors" dialog ("OBS Studio was not able to load all third-party plugins") appears although nothing failed. Tools > Plugin Manager then lists every third-party plugin as Missing, with a trash button.
• Normal start with two or more Missing entries (plugins that were uninstalled): remove one, then use the trash button or toggle of any row after it.

Reproduced in 0.1.0-beta.20261014

The released AppImage (built from 9e2325e), headless (private Xvfb and D-Bus), one profile across the starts, a small test plugin (it loads and does nothing) in the user plugin folder. The dialog was detected by its window title.

For #14005, plugin_manager/modules.json listed three plugins that do not exist (ghost-a, ghost-b, ghost-c, so they show as Missing) before two that load (the test plugin and a second test plugin that drives the window). In the Plugin Manager, a test plugin clicked the way a user does: the trash button of ghost-a, the toggle of the first test plugin (off), the trash button of ghost-c, then Save.

Proposed fix and failing test

Port both upstream PRs, crediting Warchamp7 as the author of his commits:

• #14001: loadAllPlugins() reports Success when the mode is not Full. In Safe Mode the Plugin Manager lists the cached plugins as Installed with a "Disabled" chip (no trash button) and shows a notice.
• The same for --only-bundled-plugins (not in #14001), with a notice that names the flag.
• #14008: each row keeps a copy of its ModuleInfo, and the trash button and toggle find their plugin in modules_ by module name. Upstream, isEnabledPluginsChanged() still reads the rows' copies, which never change, so turning a plugin off no longer shows the restart notice or asks to restart. Read modules_ there instead.

RED test: test_plugin_manager (new, cmocka + Qt Widgets on the offscreen platform, no display). It builds the real PluginManager, PluginManagerWindow and InstalledPluginRow against stand-ins for the frontend app and the libobs module calls. 5 of 8 cases fail today:

• a core-only load reports Success;
• Safe Mode lists cached plugins as installed and disabled, with no trash button;
• --only-bundled-plugins does the same;
• removing ghost-a and then ghost-c keeps ghost-b and both loaded plugins;
• after removing ghost-a, turning plugin-x off turns plugin-x off (not plugin-y).

Guards that pass today: a full load still reports a plugin failure; on a normal start a plugin that is gone is still Missing and can be removed; turning a plugin off asks for a restart.