nitishagar opened a new pull request, #36605:
URL: https://github.com/apache/superset/pull/36605
### SUMMARY
Fix the Pandas `SettingWithCopyWarning` that appears in logs when loading
dashboards with Histogram and Box Plot charts.
**Root Cause:** When `df.dropna()` is called, Pandas cannot guarantee
whether it returns a view or a copy. Subsequent direct column assignment
`df[column] = value` on a potential view triggers the warning.
**Fix:** Use the `.loc[]` accessor for column assignment (`df.loc[:,
column] = value`), which is the Pandas-recommended approach to avoid this
warning.
**Changes:**
- `superset/utils/pandas_postprocessing/histogram.py:57` - Use `.loc[]`
accessor
- `superset/utils/pandas_postprocessing/boxplot.py:130` - Use `.loc[]`
accessor (same pattern)
This is a cosmetic fix that eliminates warnings without changing any
functionality.
### BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF
**Before (in logs):**
superset_app | /app/superset/utils/pandas_postprocessing/histogram.py:57:
SettingWithCopyWarning:
superset_app | A value is trying to be set on a copy of a slice from a
DataFrame.
superset_app | Try using .loc[row_indexer,col_indexer] = value instead
**After:** No warning in logs.
### TESTING INSTRUCTIONS
1. Start Superset: `docker compose up`
2. Login at `http://localhost:8088` with admin credentials
3. Create or load a dashboard with a Histogram chart
4. Check logs: `docker compose logs superset_app | grep
SettingWithCopyWarning`
5. Confirm no warning appears
**Automated tests:**
```bash
pytest tests/unit_tests/pandas_postprocessing/test_histogram.py
tests/unit_tests/pandas_postprocessing/test_boxplot.py -v
All 16 tests pass.
```
**ADDITIONAL INFORMATION**
- Has associated issue: Fixes #36530
- Required feature flags:
- Changes UI
- Includes DB Migration (follow approval process in
https://github.com/apache/superset/issues/13351)
- 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
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