Add move and split redirects to the schema

assertions.test.ts

@@ -0,0 +1,36 @@
+import assert from "node:assert/strict";
+import { assertValidFeatureReference } from "./assertions";
+
+describe("assertValidReference()", function () {
+  it("throws if target ID is a move", function () {
+    assert.throws(() => {
+      assertValidFeatureReference("a", "some-moving-feature", {
+        "some-moving-feature": { kind: "moved" },
+      });
+    });
+  });
+
+  it("throws if target ID is a split", function () {
+    assert.throws(() => {
+      assertValidFeatureReference("a", "some-split-feature", {
+        "some-split-feature": { kind: "split" },
+      });
+    });
+  });
+
+  it("throws if target ID is not defined", function () {
+    assert.throws(() => {
+      assertValidFeatureReference(
+        "a",
+        "this-is-a-completely-invalid-feature",
+        {},
+      );
+    });
+  });
+
+  it("does not throw if target ID is a feature", function () {
+    assert.doesNotThrow(() => {
+      assertValidFeatureReference("a", "dom", { dom: { kind: "feature" } });
+    });
+  });
+});

assertions.ts

@@ -0,0 +1,29 @@
+import { isOrdinaryFeatureData } from "./type-guards";
+import { WebFeaturesData } from "./types.quicktype";
+
+/**
+ * Assert that a reference from one feature to another is an ordinary feature
+ * reference (i.e., it's defined and not some kind of redirect).
+ *
+ * @export
+ * @param {string} sourceId The feature that is referencing another feature
+ * @param {string} targetId The feature being referenced
+ * @param {WebFeaturesData["features"]} features Feature data
+ */
+export function assertValidFeatureReference(
+  sourceId: string,
+  targetId: string,
+  features: WebFeaturesData["features"],
+) {
+  const target: unknown = features[targetId];
+  if (target === undefined) {
+    throw new Error(`${sourceId} references a non-existent feature`);
+  }
+  if (!isOrdinaryFeatureData(target)) {
+    throw new Error(
+      `${sourceId} references a redirect "${targetId} instead of an ordinary feature ID`,
+    );
+  }
+}
+
+// TODO: assertValidSnapshotReference

features/conic-gradients.yml

@@ -8,4 +8,5 @@ status:
 compat_features:
   - css.types.gradient.conic-gradient
   - css.types.gradient.conic-gradient.doubleposition
+  - css.types.gradient.conic-gradient.single_color_stop
   - css.types.gradient.repeating-conic-gradient

features/conic-gradients.yml.dist

@@ -41,3 +41,15 @@ compat_features:
   #   safari: "12.1"
   #   safari_ios: "12.2"
   - css.types.gradient.conic-gradient.doubleposition
+
+  # baseline: low
+  # baseline_low_date: 2025-04-04
+  # support:
+  #   chrome: "135"
+  #   chrome_android: "135"
+  #   edge: "135"
+  #   firefox: "136"
+  #   firefox_android: "136"
+  #   safari: "18.4"
+  #   safari_ios: "18.4"
+  - css.types.gradient.conic-gradient.single_color_stop

features/gradients.yml

@@ -16,18 +16,22 @@ compat_features:
   - css.types.gradient.linear-gradient.interpolation_hints
   - css.types.gradient.linear-gradient.premultiplied_gradients
   - css.types.gradient.linear-gradient.to
+  - css.types.gradient.linear-gradient.single_color_stop
   - css.types.gradient.linear-gradient.unitless_0_angle
   - css.types.gradient.repeating-linear-gradient
   - css.types.gradient.repeating-linear-gradient.doubleposition
   - css.types.gradient.repeating-linear-gradient.interpolation_hints
   - css.types.gradient.repeating-linear-gradient.to
+  - css.types.gradient.repeating-linear-gradient.single_color_stop
   - css.types.gradient.repeating-linear-gradient.unitless_0_angle
   - css.types.gradient.radial-gradient
   - css.types.gradient.radial-gradient.at
   - css.types.gradient.radial-gradient.doubleposition
   - css.types.gradient.radial-gradient.interpolation_hints
   - css.types.gradient.radial-gradient.premultiplied_gradients
+  - css.types.gradient.radial-gradient.single_color_stop
   - css.types.gradient.repeating-radial-gradient
   - css.types.gradient.repeating-radial-gradient.at
   - css.types.gradient.repeating-radial-gradient.doubleposition
   - css.types.gradient.repeating-radial-gradient.interpolation_hints
+  - css.types.gradient.repeating-radial-gradient.single_color_stop

features/gradients.yml.dist

@@ -145,3 +145,18 @@ compat_features:
   #   safari_ios: "15"
   - css.types.gradient.linear-gradient.premultiplied_gradients
   - css.types.gradient.radial-gradient.premultiplied_gradients
+
+  # baseline: low
+  # baseline_low_date: 2025-04-04
+  # support:
+  #   chrome: "135"
+  #   chrome_android: "135"
+  #   edge: "135"
+  #   firefox: "136"
+  #   firefox_android: "136"
+  #   safari: "18.4"
+  #   safari_ios: "18.4"
+  - css.types.gradient.linear-gradient.single_color_stop
+  - css.types.gradient.radial-gradient.single_color_stop
+  - css.types.gradient.repeating-linear-gradient.single_color_stop
+  - css.types.gradient.repeating-radial-gradient.single_color_stop

features/numeric-separators.yml

@@ -0,0 +1,6 @@
+name: Numeric separators
+description: To improve readability for numeric literals, underscores (`_`) can be used as separators. For example, `1_050.95` is equivalent to `1050.95`.
+spec: https://tc39.es/ecma262/multipage/ecmascript-language-lexical-grammar.html#prod-NumericLiteralSeparator
+group: javascript
+compat_features:
+  - javascript.grammar.numeric_separators

features/numeric-separators.yml.dist

@@ -0,0 +1,17 @@
+# Generated from: numeric-separators.yml
+# Do not edit this file by hand. Edit the source file instead!
+
+status:
+  baseline: high
+  baseline_low_date: 2020-07-28
+  baseline_high_date: 2023-01-28
+  support:
+    chrome: "75"
+    chrome_android: "75"
+    edge: "79"
+    firefox: "70"
+    firefox_android: "79"
+    safari: "13"
+    safari_ios: "13"
+compat_features:
+  - javascript.grammar.numeric_separators

features/numeric-seperators.yml

@@ -1,6 +1,2 @@
-name: Numeric separators
-description: To improve readability for numeric literals, underscores (`_`) can be used as separators. For example, `1_050.95` is equivalent to `1050.95`.
-spec: https://tc39.es/ecma262/multipage/ecmascript-language-lexical-grammar.html#prod-NumericLiteralSeparator
-group: javascript
-compat_features:
-  - javascript.grammar.numeric_separators
+kind: moved
+redirect_target: numeric-separators

features/numeric-seperators.yml.dist

@@ -1,17 +1,6 @@
 # Generated from: numeric-seperators.yml
-# Do not edit this file by hand. Edit the source file instead!
+# This file intentionally left blank.
+# Do not edit this file.
+# The data for this feature has moved to numeric-separators.yml
 
-status:
-  baseline: high
-  baseline_low_date: 2020-07-28
-  baseline_high_date: 2023-01-28
-  support:
-    chrome: "75"
-    chrome_android: "75"
-    edge: "79"
-    firefox: "70"
-    firefox_android: "79"
-    safari: "13"
-    safari_ios: "13"
-compat_features:
-  - javascript.grammar.numeric_separators
+{}

features/single-color-gradients.yml

@@ -1,11 +1,4 @@
-name: Single color stop gradients
-description: A single color stop can be provided to the `linear-gradient()`, `radial-gradient()`, and `conic-gradient()` CSS functions, and their repeating counterparts, to create a solid color background.
-spec: https://drafts.csswg.org/css-images-4/#color-stop-syntax
-group: gradients
-compat_features:
-  - css.types.gradient.conic-gradient.single_color_stop
-  - css.types.gradient.linear-gradient.single_color_stop
-  - css.types.gradient.radial-gradient.single_color_stop
-  - css.types.gradient.repeating-conic-gradient.single_color_stop
-  - css.types.gradient.repeating-linear-gradient.single_color_stop
-  - css.types.gradient.repeating-radial-gradient.single_color_stop
+kind: split
+redirect_targets:
+  - gradients
+  - conic-gradients

features/single-color-gradients.yml.dist

@@ -1,21 +1,8 @@
 # Generated from: single-color-gradients.yml
-# Do not edit this file by hand. Edit the source file instead!
+# This file intentionally left blank.
+# Do not edit this file.
+# The data for this feature has moved to:
+#   - gradients.yml
+#   - conic-gradients.yml
 
-status:
-  baseline: low
-  baseline_low_date: 2025-04-04
-  support:
-    chrome: "135"
-    chrome_android: "135"
-    edge: "135"
-    firefox: "136"
-    firefox_android: "136"
-    safari: "18.4"
-    safari_ios: "18.4"
-compat_features:
-  - css.types.gradient.conic-gradient.single_color_stop
-  - css.types.gradient.linear-gradient.single_color_stop
-  - css.types.gradient.radial-gradient.single_color_stop
-  - css.types.gradient.repeating-conic-gradient.single_color_stop
-  - css.types.gradient.repeating-linear-gradient.single_color_stop
-  - css.types.gradient.repeating-radial-gradient.single_color_stop
+{}

index.ts

@@ -5,10 +5,12 @@ import { Temporal } from '@js-temporal/polyfill';
 import { fdir } from 'fdir';
 import YAML from 'yaml';
 import { convertMarkdown } from "./text";
-import { FeatureData, GroupData, SnapshotData, WebFeaturesData } from './types';
+import { GroupData, SnapshotData, WebFeaturesData } from './types';
 
 import { BASELINE_LOW_TO_HIGH_DURATION, coreBrowserSet, parseRangedDateString } from 'compute-baseline';
 import { Compat } from 'compute-baseline/browser-compat-data';
+import { assertValidFeatureReference } from './assertions';
+import { isMoved, isSplit } from './type-guards';
 
 // The longest name allowed, to allow for compact display.
 const nameMaxLength = 80;
@@ -120,7 +122,7 @@ function* identifiers(value) {
 // Map from BCD keys/paths to web-features identifiers.
 const bcdToFeatureId: Map<string, string> = new Map();
 
-const features: { [key: string]: FeatureData } = {};
+const features: WebFeaturesData["features"] = {};
 for (const [key, data] of yamlEntries('features')) {
     // Draft features reserve an identifier but aren't complete yet. Skip them.
     if (data[draft]) {
@@ -130,6 +132,11 @@ for (const [key, data] of yamlEntries('features')) {
         continue;
     }
 
+    // Attach `kind: feature` to ordinary features
+    if (!isMoved(data) && !isSplit(data)) {
+        data.kind = "feature";
+    }
+
     // Convert markdown to text+HTML.
     if (data.description) {
         const { text, html } = convertMarkdown(data.description);
@@ -185,12 +192,25 @@ for (const [key, data] of yamlEntries('features')) {
     features[key] = data;
 }
 
-// Assert that discouraged feature's alternatives are valid
 for (const [id, feature] of Object.entries(features)) {
-    for (const alternative of feature.discouraged?.alternatives ?? []) {
-        if (!(alternative in features)) {
-            throw new Error(`${id}'s alternative "${alternative}" is not a valid feature ID`);
-        }
+    const { kind } = feature;
+    switch (kind) {
+        case "feature":
+            for (const alternative of feature.discouraged?.alternatives ?? []) {
+                assertValidFeatureReference(id, alternative, features)
+            }
+            break;
+        case "moved":
+            assertValidFeatureReference(id, feature.redirect_target, features);
+            break;
+        case "split":
+            for (const target of feature.redirect_targets) {
+                assertValidFeatureReference(id, target, features);
+            }
+            break;
+        default:
+            kind satisfies never;
+            throw new Error(`Unhandled feature kind ${kind}}`);
     }
 }
 

package.json

@@ -29,11 +29,12 @@
     "test:coverage": "npm run --workspaces test:coverage",
     "test:dist": "tsx scripts/dist.ts --check",
     "test:format": "prettier --check .",
+    "test:index": "mocha -r tsx './*.test.ts'",
     "test:lint": "npx eslint .",
     "test:schematypes": "tsx scripts/schema.ts",
     "test:specs": "tsx scripts/specs.ts",
     "test:types": "npm run --workspaces test:types && tsc",
-    "test": "npm run test:caniuse -- --quiet && npm run test:schematypes && npm run test:specs && npm run test:types && npm run test:format && npm run test:dist && npm run test --workspaces && npm run test:lint",
+    "test": "npm run test:caniuse -- --quiet && npm run test:schematypes && npm run test:specs && npm run test:types && npm run test:format && npm run test:index && npm run test:dist && npm test --workspaces && npm run test:lint",
     "update-drafts": "tsx scripts/update-drafts.ts",
     "remove-tagged-compat-features": "tsx scripts/remove-tagged-compat-features.ts && npm run format"
   },
@@ -53,6 +54,7 @@
     "fast-json-stable-stringify": "^2.1.0",
     "fdir": "^6.5.0",
     "hast-util-to-string": "^3.0.1",
+    "mocha": "^11.7.2",
     "prettier": "^3.6.2",
     "quicktype": "^23.2.6",
     "rehype-parse": "^9.0.1",

packages/compute-baseline/package.json

@@ -28,11 +28,9 @@
   "devDependencies": {
     "@types/chai": "^5.2.2",
     "@types/chai-jest-snapshot": "^1.3.8",
-    "@types/mocha": "^10.0.10",
     "c8": "^10.1.3",
     "chai": "^6.0.1",
-    "chai-jest-snapshot": "^2.0.0",
-    "mocha": "^11.7.2"
+    "chai-jest-snapshot": "^2.0.0"
   },
   "peerDependencies": {
     "@mdn/browser-compat-data": "^7.0.0"