Add support for the duplicate named capturing groups proposal

Makefile

@@ -185,15 +185,16 @@ test-test262-update-allowlist:
 
 
 new-version-checklist:
-	# @echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
-	# @echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
-	# @echo "!!!!!!                                                   !!!!!!"
-	# @echo "!!!!!!         Write any message that should             !!!!!!"
-	# @echo "!!!!!!            block the release here                 !!!!!!"
-	# @echo "!!!!!!                                                   !!!!!!"
-	# @echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
-	# @echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
-	# @exit 1
+	@echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
+	@echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
+	@echo "!!!!!!                                                   !!!!!!"
+	@echo "!!!!!!    Update minVersion in the wrapRegExp helper,    !!!!!!"
+	@echo "!!!!!!  and the requried core version in the duplicate   !!!!!!"
+	@echo "!!!!!!                 named groups plugin.              !!!!!!"
+	@echo "!!!!!!                                                   !!!!!!"
+	@echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
+	@echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
+	@exit 1
 
 new-version:
 	$(MAKE) new-version-checklist

packages/babel-helper-create-regexp-features-plugin/src/features.ts

@@ -5,6 +5,7 @@ export const FEATURES = Object.freeze({
   namedCaptureGroups: 1 << 3,
   unicodeSetsFlag_syntax: 1 << 4,
   unicodeSetsFlag: 1 << 5,
+  duplicateNamedCaptureGroups: 1 << 6,
 });
 
 // We can't use a symbol because this needs to always be the same, even if

packages/babel-helper-create-regexp-features-plugin/src/index.ts

@@ -1,5 +1,11 @@
 import rewritePattern from "regexpu-core";
-import { featuresKey, FEATURES, enableFeature, runtimeKey } from "./features";
+import {
+  featuresKey,
+  FEATURES,
+  enableFeature,
+  runtimeKey,
+  hasFeature,
+} from "./features";
 import { generateRegexpuOptions, canSkipRegexpu, transformFlags } from "./util";
 import type { NodePath } from "@babel/traverse";
 
@@ -44,16 +50,37 @@ export function createRegExpFeaturePlugin({
       const features = file.get(featuresKey) ?? 0;
       let newFeatures = enableFeature(features, FEATURES[feature]);
 
-      const { useUnicodeFlag, runtime = true } = options;
+      const { useUnicodeFlag, runtime } = options;
       if (useUnicodeFlag === false) {
         newFeatures = enableFeature(newFeatures, FEATURES.unicodeFlag);
       }
       if (newFeatures !== features) {
         file.set(featuresKey, newFeatures);
       }
 
-      if (!runtime) {
-        file.set(runtimeKey, false);
+      if (runtime !== undefined) {
+        if (
+          file.has(runtimeKey) &&
+          file.get(runtimeKey) !== runtime &&
+          // TODO(Babel 8): Remove this check. It's necessary because in Babel 7
+          // we allow multiple copies of transform-named-capturing-groups-regex
+          // with conflicting 'runtime' options.
+          hasFeature(newFeatures, FEATURES.duplicateNamedCaptureGroups)
+        ) {
+          throw new Error(
+            `The 'runtime' option must be the same for ` +
+              `'@babel/plugin-transform-named-capturing-groups-regex' and ` +
+              `'@babel/plugin-proposal-duplicate-named-capturing-groups-regex'.`,
+          );
+        }
+        // TODO(Babel 8): Remove this check and always set it.
+        // It's necessary because in Babel 7 we allow multiple copies of
+        // transform-named-capturing-groups-regex with conflicting 'runtime' options.
+        if (feature === "namedCaptureGroups") {
+          if (!runtime || !file.has(runtimeKey)) file.set(runtimeKey, runtime);
+        } else {
+          file.set(runtimeKey, runtime);
+        }
       }
 
       if (!file.has(versionKey) || file.get(versionKey) < version) {
@@ -68,13 +95,24 @@ export function createRegExpFeaturePlugin({
         const features = file.get(featuresKey);
         const runtime = file.get(runtimeKey) ?? true;
 
-        const regexpuOptions = generateRegexpuOptions(features);
-        if (canSkipRegexpu(node, regexpuOptions)) return;
+        const regexpuOptions = generateRegexpuOptions(node.pattern, features);
+        if (canSkipRegexpu(node, regexpuOptions)) {
+          return;
+        }
 
-        const namedCaptureGroups: Record<string, number> = {};
+        const namedCaptureGroups: Record<string, number | number[]> = {
+          __proto__: null,
+        };
         if (regexpuOptions.namedGroups === "transform") {
           regexpuOptions.onNamedGroup = (name, index) => {
-            namedCaptureGroups[name] = index;
+            const prev = namedCaptureGroups[name];
+            if (typeof prev === "number") {
+              namedCaptureGroups[name] = [prev, index];
+            } else if (Array.isArray(prev)) {
+              prev.push(index);
+            } else {
+              namedCaptureGroups[name] = index;
+            }
           };
         }
 

packages/babel-helper-create-regexp-features-plugin/src/util.ts

@@ -3,7 +3,10 @@ import { FEATURES, hasFeature } from "./features";
 
 import type { RegexpuOptions } from "regexpu-core";
 
-export function generateRegexpuOptions(toTransform: number): RegexpuOptions {
+export function generateRegexpuOptions(
+  pattern: string,
+  toTransform: number,
+): RegexpuOptions {
   type Experimental = 1;
 
   const feat = <Stability extends 0 | 1 = 0>(
@@ -13,14 +16,29 @@ export function generateRegexpuOptions(toTransform: number): RegexpuOptions {
     return hasFeature(toTransform, FEATURES[name]) ? ok : false;
   };
 
+  const featDuplicateNamedGroups = (): "transform" | false => {
+    if (!feat("duplicateNamedCaptureGroups")) return false;
+
+    // This can return false positive, for example for /\(?<a>\)/.
+    // However, it's such a rare occurrence that it's ok to compile
+    // the regexp even if we only need to compile regexps with
+    // duplicate named capturing groups.
+    const regex = /\(\?<([^>]+)>/g;
+    const seen = new Set();
+    for (let match; (match = regex.exec(pattern)); seen.add(match[1])) {
+      if (seen.has(match[1])) return "transform";
+    }
+    return false;
+  };
+
   return {
     unicodeFlag: feat("unicodeFlag"),
     unicodeSetsFlag:
       feat<Experimental>("unicodeSetsFlag") ||
       feat<Experimental>("unicodeSetsFlag_syntax", "parse"),
     dotAllFlag: feat("dotAllFlag"),
     unicodePropertyEscapes: feat("unicodePropertyEscape"),
-    namedGroups: feat("namedCaptureGroups"),
+    namedGroups: feat("namedCaptureGroups") || featDuplicateNamedGroups(),
     onNamedGroup: () => {},
   };
 }

packages/babel-helper-create-regexp-features-plugin/test/fixtures/runtime/conflict-false-true/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["transform-named-capturing-groups-regex", { "runtime": true }],
+    ["proposal-duplicate-named-capturing-groups-regex", { "runtime": false }]
+  ],
+  "throws": "The 'runtime' option must be the same for '@babel/plugin-transform-named-capturing-groups-regex' and '@babel/plugin-proposal-duplicate-named-capturing-groups-regex'."
+}

packages/babel-helper-create-regexp-features-plugin/test/fixtures/runtime/conflict-true-false/input.mjs

@@ -0,0 +1 @@
+/(?<year>\d{4})/

packages/babel-helper-create-regexp-features-plugin/test/fixtures/runtime/conflict-true-false/options.json

@@ -0,0 +1,7 @@
+{
+  "plugins": [
+    ["transform-named-capturing-groups-regex", { "runtime": false }],
+    ["proposal-duplicate-named-capturing-groups-regex", { "runtime": true }]
+  ],
+  "throws": "The 'runtime' option must be the same for '@babel/plugin-transform-named-capturing-groups-regex' and '@babel/plugin-proposal-duplicate-named-capturing-groups-regex'."
+}

packages/babel-helper-create-regexp-features-plugin/test/fixtures/runtime/plugin-transform-named-capturing-groups-regex-runtime-false-not-overwritten/input.mjs

@@ -0,0 +1 @@
+/(?<year>\d{4})/

packages/babel-helpers/src/helpers-generated.ts

@@ -39,6 +39,6 @@ export default Object.freeze({
   ),
   wrapRegExp: helper(
     "7.2.6",
-    'import setPrototypeOf from"setPrototypeOf";import inherits from"inherits";export default function _wrapRegExp(){_wrapRegExp=function(re,groups){return new BabelRegExp(re,void 0,groups)};var _super=RegExp.prototype,_groups=new WeakMap;function BabelRegExp(re,flags,groups){var _this=new RegExp(re,flags);return _groups.set(_this,groups||_groups.get(re)),setPrototypeOf(_this,BabelRegExp.prototype)}function buildGroups(result,re){var g=_groups.get(re);return Object.keys(g).reduce((function(groups,name){return groups[name]=result[g[name]],groups}),Object.create(null))}return inherits(BabelRegExp,RegExp),BabelRegExp.prototype.exec=function(str){var result=_super.exec.call(this,str);return result&&(result.groups=buildGroups(result,this)),result},BabelRegExp.prototype[Symbol.replace]=function(str,substitution){if("string"==typeof substitution){var groups=_groups.get(this);return _super[Symbol.replace].call(this,str,substitution.replace(/\\$<([^>]+)>/g,(function(_,name){return"$"+groups[name]})))}if("function"==typeof substitution){var _this=this;return _super[Symbol.replace].call(this,str,(function(){var args=arguments;return"object"!=typeof args[args.length-1]&&(args=[].slice.call(args)).push(buildGroups(args,_this)),substitution.apply(this,args)}))}return _super[Symbol.replace].call(this,str,substitution)},_wrapRegExp.apply(this,arguments)}',
+    'import setPrototypeOf from"setPrototypeOf";import inherits from"inherits";export default function _wrapRegExp(){_wrapRegExp=function(re,groups){return new BabelRegExp(re,void 0,groups)};var _super=RegExp.prototype,_groups=new WeakMap;function BabelRegExp(re,flags,groups){var _this=new RegExp(re,flags);return _groups.set(_this,groups||_groups.get(re)),setPrototypeOf(_this,BabelRegExp.prototype)}function buildGroups(result,re){var g=_groups.get(re);return Object.keys(g).reduce((function(groups,name){var i=g[name];if("number"==typeof i)groups[name]=result[i];else{for(var k=0;void 0===result[i[k]]&&k+1<i.length;)k++;groups[name]=result[i[k]]}return groups}),Object.create(null))}return inherits(BabelRegExp,RegExp),BabelRegExp.prototype.exec=function(str){var result=_super.exec.call(this,str);return result&&(result.groups=buildGroups(result,this)),result},BabelRegExp.prototype[Symbol.replace]=function(str,substitution){if("string"==typeof substitution){var groups=_groups.get(this);return _super[Symbol.replace].call(this,str,substitution.replace(/\\$<([^>]+)>/g,(function(_,name){return"$"+groups[name]})))}if("function"==typeof substitution){var _this=this;return _super[Symbol.replace].call(this,str,(function(){var args=arguments;return"object"!=typeof args[args.length-1]&&(args=[].slice.call(args)).push(buildGroups(args,_this)),substitution.apply(this,args)}))}return _super[Symbol.replace].call(this,str,substitution)},_wrapRegExp.apply(this,arguments)}',
   ),
 });

packages/babel-helpers/src/helpers/wrapRegExp.js

@@ -56,7 +56,16 @@ export default function _wrapRegExp() {
 
     var g = _groups.get(re);
     return Object.keys(g).reduce(function (groups, name) {
-      groups[name] = result[g[name]];
+      var i = g[name];
+      if (typeof i === "number") groups[name] = result[i];
+      else {
+        // i is an array of indexes
+        var k = 0;
+        // if no group matched, we stop at k = i.length - 1 and then
+        // we store result[i[i.length - 1]] which is undefined.
+        while (result[i[k]] === undefined && k + 1 < i.length) k++;
+        groups[name] = result[i[k]];
+      }
       return groups;
     }, Object.create(null));
   }

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/.npmignore

@@ -0,0 +1,3 @@
+src
+test
+*.log

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/README.md

@@ -0,0 +1,19 @@
+# @babel/plugin-proposal-duplicate-named-capturing-groups-regex
+
+> Compile regular expressions using duplicate named groups to index-based groups.
+
+See our website [@babel/plugin-proposal-duplicate-named-capturing-groups-regex](https://babeljs.io/docs/en/babel-plugin-proposal-duplicate-named-capturing-groups-regex) for more information.
+
+## Install
+
+Using npm:
+
+```sh
+npm install --save-dev @babel/plugin-proposal-duplicate-named-capturing-groups-regex
+```
+
+or using yarn:
+
+```sh
+yarn add @babel/plugin-proposal-duplicate-named-capturing-groups-regex --dev
+```

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/package.json

@@ -0,0 +1,52 @@
+{
+  "name": "@babel/plugin-proposal-duplicate-named-capturing-groups-regex",
+  "version": "7.18.6",
+  "description": "Compile regular expressions using duplicate named groups to index-based groups.",
+  "homepage": "https://babel.dev/docs/en/next/babel-plugin-proposal-duplicate-named-capturing-groups-regex",
+  "license": "MIT",
+  "publishConfig": {
+    "access": "public"
+  },
+  "main": "./lib/index.js",
+  "keywords": [
+    "babel-plugin",
+    "regex",
+    "regexp",
+    "regular expressions"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/babel/babel.git",
+    "directory": "packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex"
+  },
+  "bugs": "https://github.com/babel/babel/issues",
+  "dependencies": {
+    "@babel/helper-create-regexp-features-plugin": "workspace:^",
+    "@babel/helper-plugin-utils": "workspace:^"
+  },
+  "peerDependencies": {
+    "@babel/core": "^7.0.0"
+  },
+  "devDependencies": {
+    "@babel/core": "workspace:^",
+    "@babel/helper-plugin-test-runner": "workspace:^",
+    "core-js": "^3.22.1"
+  },
+  "engines": {
+    "node": ">=6.9.0"
+  },
+  "author": "The Babel Team (https://babel.dev/team)",
+  "conditions": {
+    "USE_ESM": [
+      {
+        "type": "module"
+      },
+      null
+    ]
+  },
+  "exports": {
+    ".": "./lib/index.js",
+    "./package.json": "./package.json"
+  },
+  "type": "commonjs"
+}

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/src/index.ts

@@ -0,0 +1,20 @@
+/* eslint-disable @babel/development/plugin-name */
+import { createRegExpFeaturePlugin } from "@babel/helper-create-regexp-features-plugin";
+import { declare } from "@babel/helper-plugin-utils";
+
+export interface Options {
+  runtime?: boolean;
+}
+
+export default declare((api, options: Options) => {
+  const { runtime } = options;
+  if (runtime !== undefined && typeof runtime !== "boolean") {
+    throw new Error("The 'runtime' option must be boolean");
+  }
+
+  return createRegExpFeaturePlugin({
+    name: "proposal-duplicate-named-capturing-groups-regex",
+    feature: "duplicateNamedCaptureGroups",
+    options: { runtime },
+  });
+});

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/runtime/basic/input.js

@@ -0,0 +1 @@
+/(?:(?<year>\d\d\d\d)|(?<year>\d\d))-(?<month>\d\d)/;

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/runtime/basic/output.js

@@ -0,0 +1,5 @@
+/*#__PURE__*/
+babelHelpers.wrapRegExp(/(?:(\d\d\d\d)|(\d\d))\x2D(\d\d)/, {
+  year: [1, 2],
+  month: 3
+});

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/runtime/exec.js

@@ -0,0 +1,5 @@
+let regexp = /(?<named>a)|(?<named>b)|c/;
+
+expect("a".match(regexp).groups).toEqual({ named: "a" });
+expect("b".match(regexp).groups).toEqual({ named: "b" });
+expect("c".match(regexp).groups).toEqual({ named: undefined });

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/runtime/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["proposal-duplicate-named-capturing-groups-regex"]
+}

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/syntax/basic/input.js

@@ -0,0 +1 @@
+/(?:(?<year>\d\d\d\d)|(?<year>\d\d)) is \k<year>/;

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/syntax/basic/output.js

@@ -0,0 +1 @@
+/(?:(\d\d\d\d)|(\d\d)) is \1\2/;

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/syntax/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [
+    ["proposal-duplicate-named-capturing-groups-regex", { "runtime": false }]
+  ]
+}

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/syntax/unique-name-not-transformed/input.js

@@ -0,0 +1 @@
+/(?<year>\d\d\d\d) is \k<year>/;

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/syntax/unique-name-not-transformed/output.js

@@ -0,0 +1 @@
+/(?<year>\d\d\d\d) is \k<year>/;

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/syntax/unique-name-with-named-groups-plugin/input.js

@@ -0,0 +1 @@
+/(?<year>\d\d\d\d) is \k<year>/;

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/syntax/unique-name-with-named-groups-plugin/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    ["proposal-duplicate-named-capturing-groups-regex", { "runtime": false }],
+    ["transform-named-capturing-groups-regex", { "runtime": false }]
+  ]
+}

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/syntax/unique-name-with-named-groups-plugin/output.js

@@ -0,0 +1 @@
+/(\d\d\d\d) is \1/;

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/basic/input.js

@@ -0,0 +1 @@
+"foo".match(/(?<double>.)\k<double>/);

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/basic/output.js

@@ -0,0 +1,3 @@
+"foo".match( /*#__PURE__*/babelHelpers.wrapRegExp(/(.)\1/, {
+  double: 1
+}));

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/looks-like-a-group-unicode/input.js

@@ -0,0 +1 @@
+/no-groups-\(?<looks-like-a-group>looks\)\u{10000}/u;

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/looks-like-a-group-unicode/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": [
+    "transform-named-capturing-groups-regex",
+    "transform-unicode-regex"
+  ]
+}

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/looks-like-a-group-unicode/output.js

@@ -0,0 +1 @@
+/no\x2Dgroups\x2D\(?<looks\x2Dlike\x2Da\x2Dgroup>looks\)(?:\uD800\uDC00)/;

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/looks-like-a-group/input.js

@@ -0,0 +1 @@
+/no-groups-\(?<looks-like-a-group>looks\)/;

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/looks-like-a-group/output.js

@@ -0,0 +1 @@
+/no\x2Dgroups\x2D\(?<looks\x2Dlike\x2Da\x2Dgroup>looks\)/;

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/only-when-named-groups/input.js

@@ -0,0 +1 @@
+"foo".match(/(.)\1/);

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/only-when-named-groups/output.js

@@ -0,0 +1 @@
+"foo".match(/(.)\1/);

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/options.json

@@ -0,0 +1,3 @@
+{
+  "plugins": ["transform-named-capturing-groups-regex"]
+}

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/skips-anonymous-capturing-groups/input.js

@@ -0,0 +1 @@
+"abba".match(/(.)(?<n>.)\k<n>\1/);

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/skips-anonymous-capturing-groups/output.js

@@ -0,0 +1,3 @@
+"abba".match( /*#__PURE__*/babelHelpers.wrapRegExp(/(.)(.)\2\1/, {
+  n: 2
+}));

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/test-method/input.js

@@ -0,0 +1 @@
+/^(?<x>.)\k<x>$/.test("aa");

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/fixtures/wrapper/test-method/output.js

@@ -0,0 +1 @@
+/^(.)\1$/.test("aa");

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/index.js

@@ -0,0 +1,3 @@
+import runner from "@babel/helper-plugin-test-runner";
+
+runner(import.meta.url);

packages/babel-plugin-proposal-duplicate-named-capturing-groups-regex/test/package.json

@@ -0,0 +1 @@
+{ "type": "module" }