fix(table): preserve column order in DefaultTableManager select/drop#9235
Merged
kirangadhave merged 2 commits intomainfrom Apr 17, 2026
Merged
fix(table): preserve column order in DefaultTableManager select/drop#9235kirangadhave merged 2 commits intomainfrom
kirangadhave merged 2 commits intomainfrom
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Pull request overview
Fixes non-deterministic column reordering for mo.ui.table when backed by plain Python data structures (list[dict] and dict[str, list]) by making select_columns/drop_columns preserve caller/original column order. This addresses export/download scrambling caused by set iteration/differences.
Changes:
- Update
DefaultTableManager.select_columnsto preserve requested column order for both row-major and column-major data. - Update
DefaultTableManager.drop_columnsto preserve original column order when dropping columns. - Add Hypothesis property tests asserting column-order invariants for select/drop in both data layouts.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
marimo/_plugins/ui/_impl/tables/default_table.py |
Makes column selection/dropping order-preserving for plain-Python table data. |
tests/_plugins/ui/_impl/tables/test_default_table.py |
Adds property-based tests to lock in order-preservation behavior. |
mscolnick
approved these changes
Apr 17, 2026
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🚀 Development release published. You may be able to view the changes at https://marimo.app?v=0.23.2-dev44 |
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Closes #9219.
Summary
mo.ui.tablewith plain Python data (list[dict]/dict[str, list]) was scrambling column order on every export. The fix makesselect_columnsanddrop_columnskeep the caller's column order on both the row-major and column-major paths.Cause
drop_columnsdid a set-difference, and the row-majorselect_columnsiterated a set. Set order depends onPYTHONHASHSEED, so it was random.Pandas/polars DataFrames weren't affected — they go through
NarwhalsTableManager.drop_columnswhich defers to the DataFrame's owndrop().Tests
Four hypothesis property tests in
test_default_table.pypin the invariant: for any column list and any drop/select subset, output order matches the original.