Fix DBT converts PERCENTILE_DISC to PERCENTILE_CONT on round-trip

[MonkeyCanCode]

Summary

Currently _extract_agg_info from https://github.com/apache/ossie/blob/main/converters/dbt/src/ossie_dbt/expression_utils.py#L96 is parse both exp.PercentileCont and exp.PercentileDisc into the same (agg_type, bare_col, percentile) which dropped the discrete flag. The rebuild later on didn't set use_discrete_percentile (which default to False) from https://github.com/apache/ossie/blob/main/converters/dbt/src/ossie_dbt/osi_to_msi.py#L287. Thereforce, a later MSI → OSI pass emits PERCENTILE_CONT instead of honoring original PERCENTILE_DISC when in-used.

To fix this problem, I added one extra field use_discrete_percentile in _extract_agg_info as return value.

Here is the local test validation:

➜  dbt git:(dbt_from_PERCENTILE_DISC_2_PERCENTILE_CONT) ✗ uv run pytest
==================================================================================================================================================== test session starts =====================================================================================================================================================
platform darwin -- Python 3.11.13, pytest-9.1.1, pluggy-1.6.0
rootdir: /Users/yong/Desktop/GitHome/ossie/converters/dbt
configfile: pyproject.toml
testpaths: tests
plugins: syrupy-5.5.3
collected 100 items

tests/test_msi_to_osi.py ..................................................................                                                                                                                                                                                                                            [ 66%]
tests/test_osi_to_msi.py ..................................                                                                                                                                                                                                                                                            [100%]

-------------------------------------------------------------------------------------------------------------------------------------------------- snapshot report summary ---------------------------------------------------------------------------------------------------------------------------------------------------
5 snapshots passed.
==================================================================================================================================================== 100 passed in 0.36s =====================================================================================================================================================

Related Issues

Checklist

Specification

• Spec changes are included in core-spec/ and follow the existing structure
• Spec changes have been discussed on the mailing list or in a linked issue
• Breaking changes to the spec are clearly called out in the summary

Ontology

• Ontology changes in ontology/ are consistent with spec changes
• New or modified terms are defined and documented

Converters

• Converter logic in converters/ is updated to reflect spec or ontology changes
• New converters include tests under the converter's test directory

Validation

• Validation rules in validation/ are updated if the spec changed
• New validation cases are covered by tests

Documentation

• docs/ is updated to reflect any user-facing changes
• New features or behaviors are documented with examples where appropriate
• CONTRIBUTING.md is updated if the contribution process changed

Examples

• examples/ are added or updated for any new spec constructs or converter support

Tests

• All existing tests pass (pytest / CI green)
• New functionality is covered by tests

Compliance

• ASF license headers are present on all new source files
• No third-party dependencies are added without PMC/IPMC approval

[MonkeyCanCode]

@QMalcolm mind take a look?

[Copilot]

🟢 Approval recommended

The fix is small, localized, and includes a targeted regression test that confirms the discrete percentile flag is preserved through the round-trip.

Pull request overview

This PR fixes a DBT converter round-trip bug where PERCENTILE_DISC expressions were parsed and rebuilt as PERCENTILE_CONT, losing the discrete percentile flag during OSSIE ↔ MSI conversions.

Changes:

• Extend _extract_agg_info() to preserve whether the parsed percentile aggregate is discrete (PERCENTILE_DISC) vs continuous (PERCENTILE_CONT).
• Populate use_discrete_percentile in PydanticMeasureAggregationParameters when converting OSSIE → MSI.
• Add a round-trip test ensuring use_discrete_percentile=True survives MSI → OSSIE → MSI.

File summaries

File	Description
converters/dbt/src/ossie_dbt/expression_utils.py	Preserve discrete-vs-continuous percentile info during aggregation parsing.
converters/dbt/src/ossie_dbt/ossie_to_msi.py	Thread use_discrete_percentile into MSI aggregation params for percentile metrics.
converters/dbt/tests/test_ossie_to_msi.py	Add regression test validating PERCENTILE_DISC round-trips correctly.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 1
• Review effort level: Lite

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[MonkeyCanCode]

Not in scope of this change. I can create a follow up to fix those doc-string later.