superset2/SCOPE.md

SCOPE: Remove the legacy viz pipeline (explore_json + viz.py)

This file is a working tracker for the remove-legacy-viz-pipeline feature branch. It accumulates everything done on this branch and will be distilled into the final PR body. It is deleted before the feature branch merges to master. Companion file: UPDATES.md staging entries destined for UPDATING.md.

Goal

Migrate every remaining useLegacyApi: true viz plugin to the v1 /api/v1/chart/data endpoint (adding buildQuery.ts + post_processing operations / transformProps reshaping as needed), then delete the deprecated explore_json endpoints and superset/viz.py entirely, and drop the legacy- prefix from the surviving plugin package names. Both endpoints have carried @deprecated(eol_version="5.0.0") gates; this branch is the EOL.

Inventory: the 15 remaining legacy viz types

#	viz_type	Plugin	Strategy	Status
1	para	legacy-plugin-chart-parallel-coordinates	Convert in place (pass-through)	⬜
2	country_map	legacy-plugin-chart-country-map	Convert in place (select/rename)	⬜
3	bullet	legacy-preset-chart-nvd3/Bullet	Convert in place (single metric)	⬜
4	chord	legacy-plugin-chart-chord	Convert in place (matrix in transformProps)	⬜
5	world_map	legacy-plugin-chart-world-map	Convert in place (country join in JS)	⬜
6	paired_ttest	legacy-plugin-chart-paired-t-test	Convert in place (pivot op)	⬜
7	time_table	src/visualizations/TimeTable	Convert in place (pivot op)	⬜
8	cal_heatmap	legacy-plugin-chart-calendar	Convert in place (pivot + epoch keys in JS)	⬜
9	horizon	legacy-plugin-chart-horizon	Convert in place (timeseries pipeline)	⬜
10	rose	legacy-plugin-chart-rose	Convert in place (timeseries pipeline)	⬜
11	time_pivot	legacy-preset-chart-nvd3/TimePivot	Convert in place (pivot + rank in JS)	⬜
12	bubble	legacy-preset-chart-nvd3/Bubble	Retarget → bubble_v2 (MigrateViz exists, needs Alembic revision)	⬜
13	compare	legacy-preset-chart-nvd3/Compare	Retarget → echarts_timeseries_line (new MigrateViz)	⬜
14	partition	legacy-plugin-chart-partition	Convert in place (hierarchy in transformProps)	⬜
15	deck_multi	preset-chart-deckgl/Multi	Client-side filter-metadata merge + stub buildQuery	⬜

"Convert in place" = keep the renderer and the viz_type key, add a modern buildQuery.ts, move the viz.py get_data() reshape into transformProps.ts, flip useLegacyApi off. No saved-chart DB migration needed since viz_type is unchanged. "Retarget" = migrate saved charts to an existing modern chart via a MigrateViz processor + Alembic revision, then delete the legacy plugin.

Phases / sub-PRs (each targets this feature branch)

Phase 0 — Dead code deletion

• superset-frontend/plugins/legacy-preset-chart-deckgl/ turned out to have zero tracked files — it was a stale local node_modules/ husk, removed locally, nothing to commit
• Delete legacy-preset-chart-nvd3/src/BoxPlot/ leftovers (unregistered; superseded by ECharts BoxPlot)
• Delete orphaned viz.py classes with no registered frontend: MapboxViz, MapLibreViz, EventFlowViz (no tests referenced them; mapbox saved charts were already migrated to point_cluster_map by revision ce6bd21901ab; the frontend point_cluster_map plugin has its own modern buildQuery, so removing MapLibreViz also fixes cache warm-up, which routed any viz_type in viz_types through the legacy path)

Phase 1 — Chart migrations (tiers 1→4, easiest first; order above)

Per-chart checklist:

• buildQuery.ts returning a buildQueryContext(...) with needed post_processing operators
• transformProps.ts ports the viz.py get_data() reshape (where not expressible as post_processing)
• useLegacyApi removed from plugin metadata
• Jest tests: buildQuery output + transformProps against fixtures captured from the legacy pipeline
• Verify legacy saved-chart form_data (granularity_sqla/time_range) flows through buildQueryContext — add a normalizing same-viz-type MigrateViz if not
• For retargets: MigrateViz processor + superset/cli/viz_migrations.py registration + Alembic revision (with MySQL MEDIUMTEXT widening) + migration tests
• UPDATES.md entry if user-facing behavior changes

Phase 2 — Backend removal

• Remove explore_json / explore_json_data / generate_json from superset/views/core.py (incl. CSV/XLSX/async branches)
• Remove CSRF exemption (superset/config.py) and GLOBAL_ASYNC_QUERIES explore_json path
• Delete superset/viz.py; unwind importers: views/utils.py (get_viz), models/slice.py (Slice.viz), commands/chart/warm_up_cache.py, common/query_context_processor.py (annotation path), security/manager.py (BaseViz overload)
• Delete tests/unit_tests/test_viz_*.py, tests/integration_tests/viz_tests.py
• Frontend plumbing: remove useLegacyApi from ChartMetadata, shouldUseLegacyApi, /explore_json/ branches in exploreUtils, chartAction.ts, ChartClient.ts, StatefulChart.tsx, DrillByModal.tsx

Phase 3 — Renames (folded into per-chart PRs where possible)

• legacy-plugin-chart-* → plugin-chart-* (dirs, npm names, file: deps, MainPreset imports, Storybook/docs)
• Resolve what remains of legacy-preset-chart-nvd3 (bullet, time_pivot survivors)
• Drop "(legacy)" suffixes from user-facing chart names

Log of work completed

(append entries as sub-PRs merge: date, sub-PR #, summary)

• 2026-07-02 — Phase 0: removed orphaned viz.py classes (MapboxViz, MapLibreViz, EventFlowViz, −204 lines) and the unregistered nvd3 BoxPlot story leftovers. Verified: ruff clean, tests/unit_tests/test_viz_* pass.

Decisions

• compare → migrating to echarts_timeseries_line; nvd3's interactive % rebasing is not preserved (flagged in UPDATES.md).
• partition → attempting convert-in-place; if the transformProps port proves unmaintainable, fall back to proposing deprecation on dev@.
• Feature branch lives on apache/superset so phase PRs can target it. Tracking files (SCOPE.md, UPDATES.md) are stripped before final merge.

Open questions

(record anything needing Evan's / community input)