See comment in #11678 (comment)

There is an issue that plugins/$pluginName/config/config.php in each plugin is loaded alphabetically. Ideally, the config.php of a required plugin should have less of a priority so that a plugin that requires another plugin, can overwrite a DI setting of the required plugin.

Meaning if a plugin Acc requires a plugin Cli, then config for Cli should be loaded first, then Acc because Acc requires Cli. This way Acc could overwrite any DI setting from Cli.

Currently, config.php files are loaded as they are defined in config.ini.php which is usually alphabetically because of https://github.com/piwik/piwik/blob/3.0.4-b2/core/Plugin/Manager.php#L209-L212 and https://github.com/piwik/piwik/blob/3.0.4-b2/core/Application/Kernel/PluginList.php#L114 (if config file is writable and not changed manually).

I presume we could solve it by sorting the plugin list differently in https://github.com/piwik/piwik/blob/3.0.4-b2/core/Plugin/Manager.php#L209-L212 where we list custom plugins first alphabetically, but if there is required plugin we need to list that sort. As this involves looking into plugin.json files, we should not do this in the PluginList.php#L114 sort() as this would be slow on each request and instead only do it when being called in updatePluginsConfig https://github.com/piwik/piwik/blob/3.0.4-b2/core/Plugin/Manager.php#L209-L212