feat(extensions): expose Superset color schemes via @apache-superset/core/theme

Defines the color-scheme API contract in @apache-superset/core/theme so
extensions can enumerate and read the host's registered categorical palettes
through the federated-module boundary.

- @apache-superset/core/theme: ColorSchemeGroup enum, ColorSchemeConfig /
  SequentialSchemeConfig types, CategoricalScheme / CategoricalSchemeRegistryLike
  interfaces, and declare-only getCategoricalSchemeNames() / getSchemeColors()
  bridge functions (no runtime implementation — the host provides it, same
  pattern as authentication/navigation).
- Palette hex data stays in @superset-ui/core; the contract package exposes
  only the API surface (no duplication).
- src/core/theme supplies the host implementation, wiring
  getCategoricalSchemeRegistry() from @superset-ui/core onto
  window.superset.theme at startup, and is registered like the other namespaces.
- Adds palette coverage tests in @superset-ui/core.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

superset-frontend/packages/superset-core/src/theme/colors.test.ts

@@ -0,0 +1,26 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { ColorSchemeGroup } from '@apache-superset/core/theme';
+
+test('ColorSchemeGroup has the expected string values', () => {
+  expect(ColorSchemeGroup.Custom).toBe('custom');
+  expect(ColorSchemeGroup.Featured).toBe('featured');
+  expect(ColorSchemeGroup.Other).toBe('other');
+});

superset-frontend/packages/superset-core/src/theme/colors.ts

@@ -0,0 +1,74 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/**
+ * Grouping/tier for a color scheme — controls how it appears in the
+ * scheme picker UI (e.g. Featured palettes are shown first).
+ *
+ * Mirrors @superset-ui/core's ColorSchemeGroup; kept here so
+ * palette configs have no dependency on @superset-ui/core.
+ */
+export enum ColorSchemeGroup {
+  Custom = 'custom',
+  Featured = 'featured',
+  Other = 'other',
+}
+
+/** Plain configuration object for a categorical color scheme. */
+export interface ColorSchemeConfig {
+  id: string;
+  label?: string;
+  colors: string[];
+  description?: string;
+  isDefault?: boolean;
+  group?: ColorSchemeGroup;
+}
+
+/** Extension of ColorSchemeConfig for sequential / diverging schemes. */
+export interface SequentialSchemeConfig extends ColorSchemeConfig {
+  isDiverging?: boolean;
+}
+
+/**
+ * Minimal interface for the categorical color scheme registry.
+ * Mirrors the public surface of @superset-ui/core's ColorSchemeRegistry.
+ */
+export interface CategoricalScheme {
+  id: string;
+  label?: string;
+  colors: string[];
+}
+
+export interface CategoricalSchemeRegistryLike {
+  keys(): string[];
+  get(name: string): CategoricalScheme | null | undefined;
+}
+
+/**
+ * Returns an alphabetically sorted list of all registered categorical color
+ * scheme names. The host app provides the implementation via
+ * window.superset.theme.
+ */
+export declare function getCategoricalSchemeNames(): string[];
+
+/**
+ * Returns the color array for a named scheme, or null if not found.
+ * The host app provides the implementation via window.superset.theme.
+ */
+export declare function getSchemeColors(schemeName: string): string[] | null;

superset-frontend/packages/superset-core/src/theme/index.tsx

@@ -88,3 +88,17 @@ export type {
 // Export theme utility functions
 export * from './utils/themeUtils';
 export * from './utils';
+
+// Color scheme API — types, enum, and declare-function bridge for extensions.
+// The host app provides the runtime implementations on window.superset.theme.
+export type {
+  ColorSchemeConfig,
+  SequentialSchemeConfig,
+  CategoricalScheme,
+  CategoricalSchemeRegistryLike,
+} from './colors';
+export {
+  ColorSchemeGroup,
+  getCategoricalSchemeNames,
+  getSchemeColors,
+} from './colors';

superset-frontend/packages/superset-ui-core/test/color/colorSchemes.test.ts

@@ -24,6 +24,12 @@ import {
   CategoricalD3,
   CategoricalGoogle,
   CategoricalLyft,
+  CategoricalModernSunset,
+  CategoricalColorsOfRainbow,
+  CategoricalBlueToGreen,
+  CategoricalRedToYellow,
+  CategoricalWavesOfBlue,
+  CategoricalPresetSuperset,
   SequentialCommon,
   SequentialD3,
   CategoricalScheme,
@@ -41,22 +47,59 @@ describe('Color Schemes', () => {
         CategoricalLyft,
         CategoricalSuperset,
         CategoricalPreset,
+        CategoricalModernSunset,
+        CategoricalColorsOfRainbow,
+        CategoricalBlueToGreen,
+        CategoricalRedToYellow,
+        CategoricalWavesOfBlue,
+        CategoricalPresetSuperset,
       ].forEach(group => {
         expect(group).toBeInstanceOf(Array);
+        expect(group.length).toBeGreaterThan(0);
         group.forEach(scheme =>
           expect(scheme).toBeInstanceOf(CategoricalScheme),
         );
       });
     });
+
+    test('each scheme has a non-empty id and at least one color', () => {
+      [
+        ...CategoricalAirbnb,
+        ...CategoricalD3,
+        ...CategoricalEcharts,
+        ...CategoricalGoogle,
+        ...CategoricalLyft,
+        ...CategoricalPreset,
+        ...CategoricalSuperset,
+        ...CategoricalPresetSuperset,
+        ...CategoricalModernSunset,
+        ...CategoricalColorsOfRainbow,
+        ...CategoricalBlueToGreen,
+        ...CategoricalRedToYellow,
+        ...CategoricalWavesOfBlue,
+      ].forEach(scheme => {
+        expect(scheme.id).toBeTruthy();
+        expect(scheme.colors.length).toBeGreaterThan(0);
+      });
+    });
   });
+
   describe('sequential', () => {
     test('returns an array of SequentialScheme', () => {
       [SequentialCommon, SequentialD3].forEach(group => {
         expect(group).toBeInstanceOf(Array);
+        expect(group.length).toBeGreaterThan(0);
         group.forEach(scheme =>
           expect(scheme).toBeInstanceOf(SequentialScheme),
         );
       });
     });
+
+    test('each scheme has a non-empty id and at least two colors', () => {
+      [...SequentialCommon, ...SequentialD3].forEach(scheme => {
+        expect(scheme.id).toBeTruthy();
+        expect(scheme.colors.length).toBeGreaterThanOrEqual(2);
+      });
+    });
   });
 });

superset-frontend/src/core/index.ts

@@ -35,5 +35,6 @@ export * from './menus';
 export * from './models';
 export * from './navigation';
 export * from './sqlLab';
+export * from './theme';
 export * from './utils';
 export * from './views';

superset-frontend/src/core/theme/colors.ts

@@ -0,0 +1,45 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import { theme as themeApi } from '@apache-superset/core';
+import { getCategoricalSchemeRegistry } from '@superset-ui/core';
+import type { CategoricalSchemeRegistryLike } from '@apache-superset/core/theme';
+
+const getCategoricalSchemeNames: typeof themeApi.getCategoricalSchemeNames =
+  () => {
+    const registry =
+      getCategoricalSchemeRegistry() as CategoricalSchemeRegistryLike | null;
+    return (registry?.keys() ?? []).sort();
+  };
+
+const getSchemeColors: typeof themeApi.getSchemeColors = schemeName => {
+  const registry =
+    getCategoricalSchemeRegistry() as CategoricalSchemeRegistryLike | null;
+  return registry?.get(schemeName)?.colors ?? null;
+};
+
+/**
+ * Host implementation of the @apache-superset/core/theme color API.
+ * Spreads the contract namespace (types, enum, styling helpers) and supplies
+ * the runtime implementations for the declare-only registry bridge functions.
+ */
+export const theme: typeof themeApi = {
+  ...themeApi,
+  getCategoricalSchemeNames,
+  getSchemeColors,
+};

superset-frontend/src/core/theme/index.ts

@@ -0,0 +1,19 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+export * from './colors';

superset-frontend/src/extensions/ExtensionsStartup.tsx

@@ -31,6 +31,7 @@ import {
   navigation,
   useNavigationTracker,
   sqlLab,
+  theme,
   views,
 } from 'src/core';
 import { useSelector } from 'react-redux';
@@ -64,6 +65,7 @@ const ExtensionsStartup: React.FC<{ children?: React.ReactNode }> = ({
       menus,
       navigation,
       sqlLab,
+      theme,
       views,
     };
 

superset-frontend/src/extensions/Namespaces.ts

@@ -36,6 +36,7 @@ import type {
   menus,
   navigation,
   sqlLab,
+  theme,
   views,
 } from 'src/core';
 
@@ -50,6 +51,7 @@ export interface Namespaces {
   menus: typeof menus;
   navigation: typeof navigation;
   sqlLab: typeof sqlLab;
+  theme: typeof theme;
   views: typeof views;
 }