fix(mixed-chart): preserve order_desc and series_limit_metric in buildQuery

[sadpandajoe]

SUMMARY

In a Mixed Chart (mixed_timeseries), changing "Sort Query By" or toggling "Sort Descending" updated the displayed SQL ("View query") but did not change the rendered result.

Root cause is in the frontend query builder. MixedTimeseries/buildQuery.ts returned the full output of normalizeOrderBy(tmpQueryObject). normalizeOrderBy deletes order_desc and series_limit_metric from the object it returns, re-adding only orderby. The backend main query reads orderby (so the displayed SQL looks correct), but the series-limit subquery that decides which top-N series to show reads order_desc and series_limit_metric directly (superset/models/helpers.py: direction = sa.desc if order_desc else sa.asc, and _get_series_orderby reads series_limit_metric). With those two fields stripped, the backend QueryObject defaults order_desc to True, so the same top-N series were always selected → the result never changed.

The fix mirrors what the single-query Timeseries chart already does: spread the query object and override only orderby, preserving order_desc and series_limit_metric.

// MixedTimeseries/buildQuery.ts
return [
  {
    ...tmpQueryObject,
    orderby: normalizeOrderBy(tmpQueryObject).orderby,
  },
];

This applies symmetrically to Query A and Query B.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N/A — no visual chrome change. The behavior change is that the rendered series now respond to the sort controls (see Testing Instructions).

TESTING INSTRUCTIONS

1. Create a Mixed Chart (Mixed Timeseries) on a dataset with a dimension that produces more series than the series limit (e.g. group by a high-cardinality column with Series limit set to a small N).
2. Set "Sort Query By" to a metric and toggle "Sort Descending" on, then off.
3. Before this fix: the displayed SQL changes but the rendered top-N series stay the same.
4. After this fix: the rendered top-N series change to honor the chosen sort metric and direction, for both Query A and Query B.

Automated coverage (plugin-chart-echarts/test/MixedTimeseries/buildQuery.test.ts):

• Updated "should compile query object A/B" to assert order_desc and series_limit_metric are preserved.
• Added a regression test, preserves order_desc and series_limit_metric for both queries, asserting the sc-107146 ascending-sort repro keeps order_desc: false + series_limit_metric for both queries. Reverting only the source fix fails this test.

Run: npm run test -- plugins/plugin-chart-echarts/test/MixedTimeseries/buildQuery.test.ts

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

Reviewer / QA note — expected behavior change on existing saved charts

Preserving series_limit_metric changes the series-limit subquery's ORDER BY column, not just its direction. Previously the field was stripped, so the backend fell back to ordering the top-N prequery by the main metric; with the fix it orders by the chosen "Sort Query By" metric (helpers.py _get_series_orderby). This is the intended correctness fix, but existing saved Mixed Charts may render a different (correct) top-N series set with no user action. Please don't mistake this for a regression during QA.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.37%. Comparing base (d6ede99) to head (8513f40).
⚠️ Report is 33 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #41401      +/-   ##
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- Coverage   64.37%   64.37%   -0.01%     
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  Files        2653     2653              
  Lines      145152   145152              
  Branches    33491    33491              
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- Hits        93446    93440       -6     
- Misses      50014    50020       +6     
  Partials     1692     1692              

Flag	Coverage Δ
javascript	68.66% <100.00%> (-0.01%)	⬇️

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[Copilot]

Pull request overview

Fixes Mixed Timeseries (mixed_timeseries) query construction so changing “Sort Query By” and “Sort Descending” affects not only the displayed SQL but also the rendered top‑N series selection. The frontend now preserves order_desc and series_limit_metric while still normalizing orderby, matching the established pattern used by the single-query Timeseries chart.

Changes:

• Update MixedTimeseries buildQuery to spread the original query object and override only orderby using normalizeOrderBy(...).
• Adjust existing unit tests to assert order_desc / series_limit_metric are preserved on compiled query objects.
• Add a regression test covering the “Sort Descending off” repro for both Query A and Query B.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
superset-frontend/plugins/plugin-chart-echarts/src/MixedTimeseries/buildQuery.ts	Preserve order_desc and series_limit_metric while normalizing orderby so series-limit behavior matches user sort controls.
superset-frontend/plugins/plugin-chart-echarts/test/MixedTimeseries/buildQuery.test.ts	Update expectations and add regression coverage ensuring both Mixed queries keep order_desc/series_limit_metric.