There is a "chicken and egg" type situation that comes up while the developers are creating new brush engines for Krita. This ticket is to come up with a clear and simple way on how to solve this dilemma.
Once a preset is created for a new brush engine this is not an issue. To clarify...this situation mostly applies to developers, not artists.
From what I know, this is currently what is done in this situation.
When a new brush engine is created in code, there is no process for generating the first brush preset
**3.0 process for generating the first brush preset**
In 3.x, the work-around is to use the application's (Krita) GUI brush editor to do this. If you change a brush engine, it 'disconnects' the currently selected brush from the editor and changes the settings area to the new engine. From here, a developer can save the brush preset as the new engine type.
**4.0 process for generating the first brush preset**
In 4.0, this behavior was changed so that you cannot have a "disconnected editor" from your brush. The brush engine drop-down is a filter that filters out brush presets from the full list. It does not actively change the settings area unless a preset is selected. The original reasoning is that a brush engine is a category/filter of a brush preset, not a brush itself. The current work around is to apply this patch that allows for this brush engine settings behavior to function closer to how it did in 3.x
https://phabricator.kde.org/D6525
The patch created other issues, so it could not be merged into master
The goal of this is to come up with a good solution for generating "the first preset" for an engine. This will mostly be useful for developers...so we might not want to call it out too much