Add move and split redirects to the schema

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 +5,11 @@ 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 { isMoved, isSplit } from './type-guards';
 
 // The longest name allowed, to allow for compact display.
 const nameMaxLength = 80;
@@ -120,7 +121,7 @@ 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 +131,11 @@ 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 +191,37 @@ 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`);
+// Assert that feature references are valid
+
+function assertValidReference(sourceID: string, targetID: string): void {
+    if (targetID in features) {
+        if (isMoved(features[targetID]) || isSplit(features[targetID])) {
+            throw new Error(`${sourceID} references a redirect "${targetID}" instead of an ordinary feature ID`);
         }
+        return;
+    }
+    throw new Error(`${sourceID}'s reference to "${targetID}" is not a valid feature ID`);
+}
+
+for (const [id, feature] of Object.entries(features)) {
+    const { kind } = feature;
+    switch (kind) {
+        case "feature":
+            for (const alternative of feature.discouraged?.alternatives ?? []) {
+                assertValidReference(id, alternative);
+            }
+            break;
+        case "moved":
+            assertValidReference(id, feature.redirect_target);
+            break;
+        case "split":
+            for (const target of feature.redirect_targets) {
+                assertValidReference(id, target);
+            }
+            break;
+        default:
+            kind satisfies never;
+            throw new Error(`Unhandled feature kind ${kind}}`);
     }
 }
 

schemas/data.schema.json

@@ -44,7 +44,18 @@
       "description": "Feature identifiers and data",
       "type": "object",
       "additionalProperties": {
-        "$ref": "#/definitions/FeatureData"
+        "oneOf": [
+          {
+            "$ref": "#/definitions/FeatureData"
+          },
+          {
+            "$ref": "#/definitions/FeatureMovedData"
+          },
+          {
+            "$ref": "#/definitions/FeatureSplitData"
+          }
+        ],
+        "$comment": "Use the `kind` property as a discriminator."
       }
     },
     "groups": {
@@ -102,6 +113,9 @@
       "description": "A feature data entry",
       "type": "object",
       "properties": {
+        "kind": {
+          "const": "feature"
+        },
         "name": {
           "description": "Short name",
           "type": "string"
@@ -143,7 +157,44 @@
           "$ref": "#/definitions/Discouraged"
         }
       },
-      "required": ["name", "description", "description_html", "spec", "status"],
+      "required": [
+        "kind",
+        "name",
+        "description",
+        "description_html",
+        "spec",
+        "status"
+      ],
+      "additionalProperties": false
+    },
+    "FeatureMovedData": {
+      "description": "A feature has permanently moved to exactly one other ID",
+      "type": "object",
+      "properties": {
+        "kind": {
+          "const": "moved"
+        },
+        "redirect_target": {
+          "description": "The new ID for this feature",
+          "type": "string"
+        }
+      },
+      "required": ["kind", "redirect_target"],
+      "additionalProperties": false
+    },
+    "FeatureSplitData": {
+      "description": "A feature has split into two or more other features",
+      "type": "object",
+      "properties": {
+        "kind": {
+          "const": "split"
+        },
+        "redirect_targets": {
+          "description": "The new IDs for this feature",
+          "$ref": "#/definitions/Strings"
+        }
+      },
+      "required": ["kind", "redirect_targets"],
       "additionalProperties": false
     },
     "GroupData": {
@@ -161,6 +212,37 @@
       "required": ["name"],
       "additionalProperties": false
     },
+    "Release": {
+      "description": "Browser release information",
+      "type": "object",
+      "properties": {
+        "version": {
+          "description": "The version string, as in \"10\" or \"17.1\"",
+          "type": "string"
+        },
+        "date": {
+          "description": " The release date, as in \"2023-12-11\"",
+          "type": "string"
+        }
+      },
+      "required": ["version", "date"],
+      "additionalProperties": false
+    },
+    "SnapshotData": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "description": "Short name",
+          "type": "string"
+        },
+        "spec": {
+          "description": "Specification",
+          "type": "string"
+        }
+      },
+      "required": ["name", "spec"],
+      "additionalProperties": false
+    },
     "Status": {
       "type": "object",
       "properties": {
@@ -226,37 +308,6 @@
       "required": ["baseline", "support"],
       "additionalProperties": false
     },
-    "Release": {
-      "description": "Browser release information",
-      "type": "object",
-      "properties": {
-        "version": {
-          "description": "The version string, as in \"10\" or \"17.1\"",
-          "type": "string"
-        },
-        "date": {
-          "description": " The release date, as in \"2023-12-11\"",
-          "type": "string"
-        }
-      },
-      "required": ["version", "date"],
-      "additionalProperties": false
-    },
-    "SnapshotData": {
-      "type": "object",
-      "properties": {
-        "name": {
-          "description": "Short name",
-          "type": "string"
-        },
-        "spec": {
-          "description": "Specification",
-          "$ref": "#/definitions/URL"
-        }
-      },
-      "required": ["name", "spec"],
-      "additionalProperties": false
-    },
     "StringOrStrings": {
       "oneOf": [
         {