Incubator-superset: Word cloud chart throws an error with an "in" filter clause specified

[bryanck]

If you add a filter with an "in" clause to a word cloud chart in Superset 0.37rc1, it throws an error.

Request posted to /api/v1/chart/data:
{"datasource":{"id":21,"type":"table"},"force":false,"queries":[{"extras":{"where":""},"groupby":["app_name"],"is_timeseries":false,"metrics":[{"label":"hits"}],"order_desc":true,"orderby":[],"row_limit":100,"time_range":"Last week","timeseries_limit":0,"timeseries_limit_metric":null,"filters":[{"col":"browser","op":"in","val":["Chrome","Safari"]}],"having":"","having_filters":[],"where":""}],"result_format":"json","result_type":"full"}

Response:
HTTP code 400
{"message":"Request is incorrect: {'queries': {0: {'filters': {0: {'op': ['Must be one of: ==, !=, >, <, >=, <=, LIKE, IS NULL, IS NOT NULL, IN, NOT IN, REGEX.']}}}}}"}

This seems to be a problem with the /api/v1/chart/data endpoint. Charts that post to /superset/explore_json don't have this issue.

How to reproduce the bug

Create a new word cloud chart. Add a filter with an "in" clause, e.g. "Browser" in "Chrome","Safari".
Server sends back a 400 response code.

Environment

(please complete the following information):

• superset version: 0.37 RC 1
• python version:3.6.11
• node.js version: 12.14.1
• npm version: 6.13.4

Checklist

• [X] I have checked the superset logs for python stacktraces and included it here as text if there are any.
• [X] I have reproduced the issue with at least the latest released version of superset.
• [X] I have checked the issue tracker for the same issue and I haven't found one similar.

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[bryanck]

My guess is it is a case-sensitive mismatch here: https://github.com/apache/incubator-superset/blob/0.37/superset/charts/schemas.py#L554

[villebro]

Thanks for reporting this @bryanck ! A fix is currently under review, and will probably trigger 0.37.0rc2 once merged.