Bug 459830

Summary: Anomaly: KPluginMetaData(file) uses different search path to KPluginMetaData::findPlugins()
Product: [Frameworks and Libraries] frameworks-kcoreaddons Reporter: Jonathan Marten <jjm>
Component: generalAssignee: Alexander Lohnau <alexander.lohnau>
Status: RESOLVED FIXED    
Severity: normal CC: alexander.lohnau, kdelibs-bugs-null, nate
Priority: NOR    
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: https://invent.kde.org/frameworks/kcoreaddons/commit/4ff1f9660c634f7308a6f868fffa003b588f42e7 Version Fixed/Implemented In: 5.100
Sentry Crash Report:

Description Jonathan Marten 2022-09-29 17:54:22 UTC 
SUMMARY

KPluginMetaData::findPlugins() uses KPluginMetaDataPrivate::forEachPlugin() which prepends QCoreApplication::applicationDirPath() to the standard list of directories searched for plugins, QCoreApplication::libraryPaths().  This is obviously intended to support running uninstalled as described in https://community.kde.org/Guidelines_and_HOWTOs/Making_apps_run_uninstalled
and works.  The built but uninstalled plugins are given priority over installed plugins.

However, if a plugin is to be loaded using KPluginMetaData(const QString &file) with a relative file name, then the search path is not adjusted as above but the 'file' parameter is simply passed to QPluginLoader which uses QCoreApplication::libraryPaths() unchanged.

The effect of this is that KPluginMetaData::findPlugins() may return a plugin name which was found in the application build location, but KPluginMetaData(file), unless the 'file' is given as an absolute path, may either be unable to find the plugin (if it is not system installed) or load a different one (if it is system installed but out of date).

ADDITIONAL INFORMATION

Suggest that KPluginMetaData, when both listing and loading plugins, should use the same modified search path.  The simplest solution would be to modify QCoreApplication::libraryPaths() either at startup or temporarily, to prepend the application directory.
Comment 1 Alexander Lohnau 2022-10-13 16:57:56 UTC 
I will make a MR tomorrow, locally I have a draft + test case already.
Comment 2 Bug Janitor Service 2022-10-14 18:09:55 UTC 
A possibly relevant merge request was started @ https://invent.kde.org/frameworks/kcoreaddons/-/merge_requests/265
Comment 3 Alexander Lohnau 2022-10-22 17:58:05 UTC 
Git commit 4ff1f9660c634f7308a6f868fffa003b588f42e7 by Alexander Lohnau.
Committed on 22/10/2022 at 17:31.
Pushed by alex into branch 'master'.

KPluginMetaData: Check applicationDirPath first when resolving plugin paths

KPluginMetaData::findPlugins prepends this path to the library paths, but when we
load a plugin by name we did not take this path into account.
FIXED-IN: 5.100

M  +37   -0    autotests/kpluginmetadatatest.cpp
M  +15   -2    src/lib/plugin/kpluginmetadata.cpp

https://invent.kde.org/frameworks/kcoreaddons/commit/4ff1f9660c634f7308a6f868fffa003b588f42e7