fix(mcp): handle all chart types in column normalization and reject adhoc_filters

[sadpandajoe]

SUMMARY

Two fixes for MCP generate_chart returning an opaque validation_system_error.

Fix 1: Column normalization for all chart types

normalize_column_names() previously fell through to TableChartConfig.model_validate() for non-XY/Table chart types (pie, pivot_table, mixed_timeseries, handlebars, big_number), which raised a Pydantic ValidationError due to discriminator mismatch. That exception wasn't caught by the narrow except-tuple in ValidationPipeline._normalize_column_names and surfaced to users as an opaque validation_system_error.

Now each chart type is reconstructed with its own model class, and the except clause uses broad Exception to catch any unexpected errors during normalization.

Fix 2: Reject adhoc_filters with a clear error

When adhoc_filters (Superset's internal format) was passed in config, it was silently dropped by Pydantic's extra="ignore", giving the caller no indication that filters were not applied. Now schema_validator detects it early and returns a clear UNSUPPORTED_ADHOC_FILTERS error with guidance to use the simplified filters field instead.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N/A — backend-only change in MCP service validation.

TESTING INSTRUCTIONS

1. Run the new unit tests:

   pytest tests/unit_tests/mcp_service/chart/test_new_chart_types.py::TestAdhocFiltersDetection -v
   pytest tests/unit_tests/mcp_service/chart/validation/test_column_name_normalization.py::TestNormalizeNonXYTableChartTypes -v

2. Verify that existing tests still pass:

   pytest tests/unit_tests/mcp_service/chart/ -v

3. Manual verification via MCP:

   • Call generate_chart with a pie chart config → should no longer return validation_system_error
   • Call generate_chart with adhoc_filters in config → should return clear UNSUPPORTED_ADHOC_FILTERS error with suggestions

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

[codecov]

Codecov Report

❌ Patch coverage is 0% with 17 lines in your changes missing coverage. Please review.
✅ Project coverage is 64.41%. Comparing base (de40b58) to head (a5d556a).
⚠️ Report is 15 commits behind head on master.

Files with missing lines	Patch %	Lines
.../mcp_service/chart/validation/dataset_validator.py	0.00%	13 Missing ⚠️
superset/mcp_service/chart/validation/pipeline.py	0.00%	2 Missing ⚠️
...t/mcp_service/chart/validation/schema_validator.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #39283      +/-   ##
==========================================
- Coverage   64.42%   64.41%   -0.01%     
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  Files        2553     2553              
  Lines      132588   132602      +14     
  Branches    30758    30765       +7     
==========================================
  Hits        85416    85416              
- Misses      45686    45700      +14     
  Partials     1486     1486              

Flag	Coverage Δ
hive	39.95% <0.00%> (-0.01%)	⬇️
mysql	60.58% <0.00%> (-0.02%)	⬇️
postgres	60.67% <0.00%> (-0.02%)	⬇️
presto	41.74% <0.00%> (-0.01%)	⬇️
python	62.25% <0.00%> (-0.02%)	⬇️
sqlite	60.30% <0.00%> (-0.02%)	⬇️
unit	100.00% <ø> (ø)

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