Sort not working on alt.Y?

Hi,

Trying to sort a bar chart on another field, not getting the expected results.

My data in DataFrame:

  location	name	             score sort_order	target
0	A	Elwood Dempsey    	10	1	20
1	B	Migdalia Mcferron	23	2	25
2	B	Takisha Rodiguez	32	2	25
3	C	Aurea Heinecke	        34	3	30
4	A	Sofia Donofrio	         5	1	20
5	B	Cecile Eubanks        	56	2	25
6	D	Haley Curfman        	23	4	40
7	A	Keenan Israel	        44	1	20
8	B	Bethanie Nicosia	 9	2	25
9	C	Dominga Sterns	         4	3	30

My Altair code to display a bar chart:

alt.Chart(data).mark_bar().encode(
        alt.Y('name:N', sort= {"op": "distinct", "field": "sort_order:O"}),
        alt.X('score:Q'),
        color={"field": 'location:N', "sort": {"op": "distinct", "field": "sort_order:O"}}
        )

Result:

The legend is sorted correctly on sort_order, however Y isn’t sorted at all. Y is displayed in the order from the datasource. If I remove the Y sort attribute, Y is sorted alphabetically (as expected).

Question: is this a bug of I’m missing something?

[jakevdp]

Sorting layered charts does not work because of a bug in Vega-Lite. I believe it will be fixed in the Vega-Lite 3.0 release, which will be supported by Altair version 3.0.

[jakevdp]

See the Vega-Lite issues linked above for more information.