Fix emulation groups with transfer given emulation groups that adjust…

… capture indices
slevithan · Dec 26, 2024 · 5577cc1 · 5577cc1
1 parent 7d971b0
commit 5577cc1
Show file tree

Hide file tree

Showing 2 changed files with 57 additions and 15 deletions.
diff --git a/spec/regex-tag.spec.js b/spec/regex-tag.spec.js
@@ -167,25 +167,67 @@ describe('regex', () => {
 
       it('should adjust for emulation groups with transfer', () => {
         const transferTo1 = `$1${emulationGroupMarker}`;
-        expect(regex({subclass: true, disable: {n: true}})({raw: [`^(a)(${transferTo1}b)$`]}).exec('ab')[1]).toBe('b');
-        expect(regex({subclass: true, disable: {n: true}})({raw: [`^(?<a>a)(${transferTo1}b)$`]}).exec('ab').groups.a).toBe('b');
-        expect(regex({subclass: true, disable: {n: true}})({raw: [`^(?<a>a)(${transferTo1}b)(${transferTo1}c)$`]}).exec('abc').groups.a).toBe('c');
+        expect(regex({subclass: true, disable: {n: true}})({raw: [
+          `^(a)(${transferTo1}b)$`
+        ]}).exec('ab')[1]).toBe('b');
+        expect(regex({subclass: true, disable: {n: true}})({raw: [
+          `^(?<a>a)(${transferTo1}b)$`
+        ]}).exec('ab').groups.a).toBe('b');
+        expect(regex({subclass: true, disable: {n: true}})({raw: [
+          `^(?<a>a)(${transferTo1}b)(${transferTo1}c)$`
+        ]}).exec('abc').groups.a).toBe('c');
         // ## Documenting behavior without transfer
-        expect(regex({subclass: true, disable: {n: true}})({raw: [`^(a)(${emulationGroupMarker}b)$`]}).exec('ab')[1]).toBe('a');
-        expect(regex({subclass: true, disable: {n: true}})({raw: [`^(?<a>a)(${emulationGroupMarker}b)$`]}).exec('ab').groups.a).toBe('a');
+        expect(regex({subclass: true, disable: {n: true}})({raw: [
+          `^(a)(${emulationGroupMarker}b)$`
+        ]}).exec('ab')[1]).toBe('a');
+        expect(regex({subclass: true, disable: {n: true}})({raw: [
+          `^(?<a>a)(${emulationGroupMarker}b)$`
+        ]}).exec('ab').groups.a).toBe('a');
       });
 
       it('should adjust indices with flag d for emulation groups with transfer', () => {
         if (!envSupportsFlagD) {
           pending('requires support for flag d (Node.js 16)');
         }
         const transferTo1 = `$1${emulationGroupMarker}`;
-        expect(regex({flags: 'd', subclass: true, disable: {n: true}})({raw: [`^(a)(${transferTo1}b)$`]}).exec('ab').indices[1]).toEqual([1, 2]);
-        expect(regex({flags: 'd', subclass: true, disable: {n: true}})({raw: [`^(?<a>a)(${transferTo1}b)$`]}).exec('ab').indices.groups.a).toEqual([1, 2]);
-        expect(regex({flags: 'd', subclass: true, disable: {n: true}})({raw: [`^(?<a>a)(${transferTo1}b)(${transferTo1}c)$`]}).exec('abc').indices.groups.a).toEqual([2, 3]);
+        expect(regex({flags: 'd', subclass: true, disable: {n: true}})({raw: [
+          `^(a)(${transferTo1}b)$`
+        ]}).exec('ab').indices[1]).toEqual([1, 2]);
+        expect(regex({flags: 'd', subclass: true, disable: {n: true}})({raw: [
+          `^(?<a>a)(${transferTo1}b)$`
+        ]}).exec('ab').indices.groups.a).toEqual([1, 2]);
+        expect(regex({flags: 'd', subclass: true, disable: {n: true}})({raw: [
+          `^(?<a>a)(${transferTo1}b)(${transferTo1}c)$`
+        ]}).exec('abc').indices.groups.a).toEqual([2, 3]);
         // ## Documenting behavior without transfer
-        expect(regex({flags: 'd', subclass: true, disable: {n: true}})({raw: [`^(a)(${emulationGroupMarker}b)$`]}).exec('ab').indices[1]).toEqual([0, 1]);
-        expect(regex({flags: 'd', subclass: true, disable: {n: true}})({raw: [`^(?<a>a)(${emulationGroupMarker}b)$`]}).exec('ab').indices.groups.a).toEqual([0, 1]);
+        expect(regex({flags: 'd', subclass: true, disable: {n: true}})({raw: [
+          `^(a)(${emulationGroupMarker}b)$`
+        ]}).exec('ab').indices[1]).toEqual([0, 1]);
+        expect(regex({flags: 'd', subclass: true, disable: {n: true}})({raw: [
+          `^(?<a>a)(${emulationGroupMarker}b)$`
+        ]}).exec('ab').indices.groups.a).toEqual([0, 1]);
+      });
+
+      it('should adjust for emulation groups with transfer given emulation groups that adjust capture indices', () => {
+        if (!envSupportsFlagD) {
+          pending('requires support for flag d (Node.js 16)');
+        }
+        const egm = emulationGroupMarker;
+        const transferTo1 = `$1${egm}`;
+        const transferTo2 = `$2${egm}`;
+        const match = regex({flags: 'd', subclass: true, disable: {n: true}})({raw: [
+          `^(${egm}(${egm}.))(?<a>(${transferTo2}.))(${transferTo1}(${transferTo2}.))(?<b>.)$`
+        ]}).exec('abcd');
+        expect(match[1]).toBe('c');
+        expect(match[2]).toBe('d');
+        expect(match).toHaveSize(3);
+        expect(match.indices[1]).toEqual([2, 3]);
+        expect(match.indices[2]).toEqual([3, 4]);
+        expect(match.indices).toHaveSize(3);
+        expect(match.groups.a).toBe('c');
+        expect(match.groups.b).toBe('d');
+        expect(match.indices.groups.a).toEqual([2, 3]);
+        expect(match.indices.groups.b).toEqual([3, 4]);
       });
     });
   });

diff --git a/src/subclass.js b/src/subclass.js
@@ -111,22 +111,22 @@ function unmarkEmulationGroups(expression) {
   const marker = emulationGroupMarker.replace(/\$/g, '\\$');
   const _captureMap = [{exclude: false}];
   const _namesByIndex = {0: ''};
-  let captureNum = 0;
+  let realCaptureNum = 0;
   expression = replaceUnescaped(
     expression,
     String.raw`\((?:(?!\?)|\?<(?![=!])(?<name>[^>]+)>)(?<mark>(?:\$(?<transfer>[1-9]\d*))?${marker})?`,
     ({0: m, groups: {name, mark, transfer}}) => {
-      captureNum++;
-      if (name) {
-        _namesByIndex[captureNum] = name;
-      }
       if (mark) {
         _captureMap.push({
           exclude: true,
           transfer: transfer && +transfer,
         });
         return m.slice(0, -mark.length);
       }
+      realCaptureNum++;
+      if (name) {
+        _namesByIndex[realCaptureNum] = name;
+      }
       _captureMap.push({
         exclude: false,
       });