Error loading charts for presto table with null column types

[michellethomas]

When loading chart based on a presto table that has null column type get an error on this line because type_ is None. @villebro looks like this was added here

Expected results

Chart should load

Actual results

Error on chart

  File "/srv/superset-internal/incubator-superset/superset/db_engine_specs/base.py", line 901, in get_sqla_column_type
    match = regex.match(type_)
TypeError: expected string or bytes-like object

How to reproduce the bug

1. Create a datasource with columns that have null types
2. Try to create a chart with the datasource

Environment

(please complete the following information):

• superset version: master
• python version: 3.7

Checklist

Make sure these boxes are checked before submitting your issue - thank you!

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

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[villebro]

Thanks @michellethomas and sorry for the regression; I'll make a fix in a second 👍

[villebro]

@michellethomas I'd like to add some unit tests to minimize risk of future breakage, as currently the methods are quite light on unit tests and are fairly complex. Would you be able to provide me with a few complex nested data types that you've encountered in your env that I could use as a template for a few unit tests? Ping @john-bodley

[bkyryliuk]

Json type example:

SELECT CAST(CAST(ROW(123, 'abc', true) AS ROW(v1 BIGINT, v2 VARCHAR, v3 BOOLEAN)) AS JSON) -- JSON '[123,"abc",true]'

row type example:

SELECT
    CAST(ROW(1, 2.0) AS ROW(x BIGINT, y DOUBLE)) as simple_row

map type example:

select MAP(ARRAY['foo', 'bar'], ARRAY[1, 2]) as column

[villebro]

Thanks @bkyryliuk !