Labeled bar chart with fill encoding does not respect sorting - vega-lite

Question

I am trying to make a sorted bar chart with labels and fill encoding. But when I add the the fill encoding it breaks the sort. Via the github issues it seems like there are ways to get around this, but I can seem find a solution.
Given the spec without using the fill encoding the sorting works as expected.
{
"$schema": "https://vega.github.io/schema/vega-lite/v3.json",
"data": {
"values": [
{
"a": "A",
"b": 28,
"color": "black"
},
{
"a": "B",
"b": 55,
"color": "grey"
},
{
"a": "C",
"b": 43,
"color": "red"
}
]
},
"encoding": {
"y": {
"field": "a",
"type": "ordinal",
"sort": {
"encoding": "x",
"order": "descending"
}
},
"x": {
"field": "b",
"type": "quantitative"
}
},
"layer": [
{
"mark": "bar"
},
{
"mark": {
"type": "text",
"align": "left",
"baseline": "middle",
"dx": 3
},
"encoding": {
"text": {
"field": "b",
"type": "quantitative"
}
}
}
]
}
When you add the fill encoding to the top level encoding object it breaks the sort with the following warning
"fill": {
"field": "color",
"type": "ordinal",
"scale": null
}
[Warning] Domains that should be unioned has conflicting sort properties. Sort will be set to true.
Full vega-editor here
Is there a work around for this.
It appear to relate to the these issues (maybe) #2536, #5408

Answer 1

Yep, the underlying issue is https://github.com/vega/vega-lite/issues/5048. In this particular case, adding color to once layer adds a stack transform to one part of the dataflow but not the other so we cannot merge it. This is a great test case. Can you add this example to a new github issue so we can try to resolve it?
You can manually fix this example by disabling stacking the x encoding.
"stack": null
See this spec.