fix: pivot columns with ints for name

[betodealmeida]

SUMMARY

The pivot column post-processing is failing because some columns have ints for their names instead of strings.

Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1950, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python3.7/site-packages/flask/app.py", line 1936, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/usr/local/lib/python3.7/site-packages/flask_appbuilder/security/decorators.py", line 67, in wraps
    return f(self, *args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/superset/views/base_api.py", line 85, in wraps
    raise ex
  File "/usr/local/lib/python3.7/site-packages/superset/views/base_api.py", line 82, in wraps
    duration, response = time_function(f, self, *args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/superset/utils/core.py", line 1428, in time_function
    response = func(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/superset/utils/log.py", line 241, in wrapper
    value = f(*args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/superset/charts/api.py", line 647, in get_data
    return self.get_data_response(command, form_data=form_data)
  File "/usr/local/lib/python3.7/site-packages/superset/charts/api.py", line 545, in get_data_response
    return self.send_chart_response(result, form_data)
  File "/usr/local/lib/python3.7/site-packages/superset/charts/api.py", line 509, in send_chart_response
    result = apply_post_process(result, form_data)
  File "/usr/local/lib/python3.7/site-packages/superset/charts/post_processing.py", line 204, in apply_post_process
    processed_df = post_processor(df, form_data)
  File "/usr/local/lib/python3.7/site-packages/superset/charts/post_processing.py", line 180, in pivot_table_v2
    df.columns = [" ".join(column) for column in df.columns]
  File "/usr/local/lib/python3.7/site-packages/superset/charts/post_processing.py", line 180, in <listcomp>
    df.columns = [" ".join(column) for column in df.columns]
TypeError: sequence item 1: expected str instance, int found

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[eschutho]

That was an interesting case..

[codecov]

Codecov Report

Merging #16259 (128383d) into master (24b43be) will decrease coverage by 0.21%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master   #16259      +/-   ##
==========================================
- Coverage   76.72%   76.50%   -0.22%     
==========================================
  Files         997      997              
  Lines       53238    53241       +3     
  Branches     6772     6772              
==========================================
- Hits        40847    40734     -113     
- Misses      12161    12277     +116     
  Partials      230      230              

Flag	Coverage Δ
hive	?
mysql	81.52% <100.00%> (-0.04%)	⬇️
postgres	81.59% <100.00%> (+<0.01%)	⬆️
presto	?
python	81.68% <100.00%> (-0.43%)	⬇️
sqlite	81.19% <100.00%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
superset/charts/post_processing.py	77.01% <100.00%> (ø)
superset/reports/commands/execute.py	92.59% <100.00%> (+0.09%)	⬆️
superset/db_engines/hive.py	0.00% <0.00%> (-82.15%)	⬇️
superset/db_engine_specs/hive.py	69.80% <0.00%> (-16.87%)	⬇️
superset/db_engine_specs/presto.py	83.47% <0.00%> (-6.49%)	⬇️
superset/views/database/mixins.py	81.03% <0.00%> (-1.73%)	⬇️
superset/connectors/sqla/models.py	88.04% <0.00%> (-1.66%)	⬇️
superset/db_engine_specs/base.py	88.00% <0.00%> (-0.39%)	⬇️
superset/models/core.py	89.14% <0.00%> (-0.26%)	⬇️
superset/utils/core.py	88.97% <0.00%> (-0.13%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 24b43be...128383d. Read the comment docs.