I think Krita provides one of the most cutting edge painting features, the brushes are on point its been amazing painting experience so far… definitely gonna be my main art software. I have one concern though, the bucket tool feature is really intolerant of gaps, even with slight gaps the entire composition gets filled. Most other software like Medibang, Clip Studio offer an option to fill gap; i think it might be a good idea to implement that in Krita. It would definitely shave our painting work flow time. Please consider this upgrade it would be MAX appreciated. Thanks for reading
There is colorize mask feature for this purpose - https://docs.krita.org/en/reference_manual/tools/colorize_mask.html
Yeah, colorize mask is fantastic for stuff like that, though, I agree with Keemo_Bryan that it would be nice to have it in the normal fill tool, since it’s quicker!
As a practical workaround, you can put a ‘closure’ layer above your lineart where you manually draw thin lines to close the gaps and then use the fill tool on the colour layer with ‘Limit to current layer’ unticked in the tool options docker. Also do grow selection = 4 px (or whatever is needed to get the fill under the lineart closure to meet an adjacent region fill).
After that, you turn off the closure layer to reveal your original lineart. This has the advantage that you get to decide where the boundaries of the colour filled regions will be if there are large gaps in the original lineart.