Histogram fails to load when null values present in x-axis variable (regression from 4.1.2 -> 5.0.0rc3)

[sfirke]

Bug description

A histogram that rendered fine in 4.1.2 fails to render in 5.0.0rc3:

The issue is that there are NULL values in the x-axis variable. When I add a "Is Not Null" filter the chart renders in 5.0.0rc3.

Previously these were excluded automatically and the chart would render, which is a reasonable behavior.

I found this error message confusing as it looked like a SQL problem but the chart's underlying SQL did not change. And it's not so much "non-numeric values" as it is NULLs since this is a numeric column.

The logs:

2025-06-11 02:48:29,472:WARNING:superset.views.error_handling:Exception
Traceback (most recent call last):
  File "/app/.venv/lib/python3.10/site-packages/flask/app.py", line 1484, in full_dispatch_request
    rv = self.dispatch_request()
  File "/app/.venv/lib/python3.10/site-packages/flask/app.py", line 1469, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "/app/.venv/lib/python3.10/site-packages/flask_appbuilder/security/decorators.py", line 101, in wraps
    return f(self, *args, **kwargs)
  File "/app/superset/views/base_api.py", line 120, in wraps
    duration, response = time_function(f, self, *args, **kwargs)
  File "/app/superset/utils/core.py", line 1369, in time_function
    response = func(*args, **kwargs)
  File "/app/superset/utils/log.py", line 304, in wrapper
    value = f(*args, **kwargs)
  File "/app/superset/charts/data/api.py", line 260, in data
    return self._get_data_response(
  File "/app/superset/utils/log.py", line 304, in wrapper
    value = f(*args, **kwargs)
  File "/app/superset/charts/data/api.py", line 423, in _get_data_response
    result = command.run(force_cached=force_cached)
  File "/app/superset/commands/chart/data/get_data_command.py", line 45, in run
    payload = self._query_context.get_payload(
  File "/app/superset/common/query_context.py", line 102, in get_payload
    return self._processor.get_payload(cache_query_context, force_cached)
  File "/app/superset/common/query_context_processor.py", line 752, in get_payload
    query_results = [
  File "/app/superset/common/query_context_processor.py", line 753, in <listcomp>
    get_query_results(
  File "/app/superset/common/query_actions.py", line 227, in get_query_results
    return result_func(query_context, query_obj, force_cached)
  File "/app/superset/common/query_actions.py", line 103, in _get_full
    payload = query_context.get_df_payload(query_obj, force_cached=force_cached)
  File "/app/superset/common/query_context.py", line 123, in get_df_payload
    return self._processor.get_df_payload(
  File "/app/superset/common/query_context_processor.py", line 162, in get_df_payload
    query_result = self.get_query_result(query_obj)
  File "/app/superset/common/query_context_processor.py", line 287, in get_query_result
    df = query_object.exec_post_processing(df)
  File "/app/superset/common/query_object.py", line 452, in exec_post_processing
    df = getattr(pandas_postprocessing, operation)(df, **options)
  File "/app/superset/utils/pandas_postprocessing/histogram.py", line 56, in histogram
    raise ValueError(f"Column '{column}' contains non-numeric values")
ValueError: Column 'days_active' contains non-numeric values
2025-06-11 02:48:29,472:ERROR:superset.views.error_handling:Column 'days_active' contains non-numeric values
Traceback (most recent call last):
  File "/app/.venv/lib/python3.10/site-packages/flask/app.py", line 1484, in full_dispatch_request
    rv = self.dispatch_request()
  File "/app/.venv/lib/python3.10/site-packages/flask/app.py", line 1469, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "/app/.venv/lib/python3.10/site-packages/flask_appbuilder/security/decorators.py", line 101, in wraps
    return f(self, *args, **kwargs)
  File "/app/superset/views/base_api.py", line 120, in wraps
    duration, response = time_function(f, self, *args, **kwargs)
  File "/app/superset/utils/core.py", line 1369, in time_function
    response = func(*args, **kwargs)
  File "/app/superset/utils/log.py", line 304, in wrapper
    value = f(*args, **kwargs)
  File "/app/superset/charts/data/api.py", line 260, in data
    return self._get_data_response(
  File "/app/superset/utils/log.py", line 304, in wrapper
    value = f(*args, **kwargs)
  File "/app/superset/charts/data/api.py", line 423, in _get_data_response
    result = command.run(force_cached=force_cached)
  File "/app/superset/commands/chart/data/get_data_command.py", line 45, in run
    payload = self._query_context.get_payload(
  File "/app/superset/common/query_context.py", line 102, in get_payload
    return self._processor.get_payload(cache_query_context, force_cached)
  File "/app/superset/common/query_context_processor.py", line 752, in get_payload
    query_results = [
  File "/app/superset/common/query_context_processor.py", line 753, in <listcomp>
    get_query_results(
  File "/app/superset/common/query_actions.py", line 227, in get_query_results
    return result_func(query_context, query_obj, force_cached)
  File "/app/superset/common/query_actions.py", line 103, in _get_full
    payload = query_context.get_df_payload(query_obj, force_cached=force_cached)
  File "/app/superset/common/query_context.py", line 123, in get_df_payload
    return self._processor.get_df_payload(
  File "/app/superset/common/query_context_processor.py", line 162, in get_df_payload
    query_result = self.get_query_result(query_obj)
  File "/app/superset/common/query_context_processor.py", line 287, in get_query_result
    df = query_object.exec_post_processing(df)
  File "/app/superset/common/query_object.py", line 452, in exec_post_processing
    df = getattr(pandas_postprocessing, operation)(df, **options)
  File "/app/superset/utils/pandas_postprocessing/histogram.py", line 56, in histogram
    raise ValueError(f"Column '{column}' contains non-numeric values")
ValueError: Column 'days_active' contains non-numeric values

Screenshots/recordings

No response

Superset version

5.0.0rc3

Python version

3.9

Node version

16

Browser

Firefox

Additional context

No response

Checklist

• I have searched Superset docs and Slack and didn't find a solution to my problem.
• I have searched the GitHub issue tracker and didn't find a similar bug report.
• I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.

[dosubot]

This regression is due to stricter null handling in the backend histogram logic starting in 5.0.0rc3. The backend now converts the histogram column to numeric, and if any nulls (NaNs) remain, it raises a ValueError and blocks rendering—even if those nulls are just missing values in an otherwise numeric column. In previous versions, nulls were silently dropped and the chart rendered as expected. The frontend does not handle nulls; it expects already-cleaned data from the backend. There is currently no configuration or UI option to change this behavior—nulls are always dropped, and if any remain after conversion, the chart fails to render source.

As a workaround, you can add an "Is Not Null" filter to your chart, or preprocess your data to remove or fill nulls before rendering the histogram. If you want to see nulls handled differently (for example, binned as a separate category), the backend logic would need to be adjusted to allow this.

Let me know if you want more details on where this logic lives or how to patch it.

To reply, just mention @dosu.

---

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[rusackas]

Would you consider this a 5.0.0 blocker? CC @michael-s-molina