fix: correct regexp slash escapes

grammar.pegjs

@@ -14,6 +14,12 @@
       }
     });
   }
+
+  // https://github.com/estools/esquery/issues/68
+  // Inside all /regexp/ literals, we replace escaped-backslashes with the \x2F equivalent.
+  input = input.replaceAll(/\/((?:[^\/\\]|\\.)*?)\//g, (match) => {
+    return match.replaceAll("\\/", "\\\\x2F");
+  });
 }
 
 start
@@ -97,8 +103,12 @@ attr
     path = i:identifierName { return { type: 'literal', value: i }; }
     type = "type(" _ t:[^ )]+ _ ")" { return { type: 'type', value: t.join('') }; }
     flags = [imsu]+
-    regex = "/" d:[^/]+ "/" flgs:flags? { return {
-      type: 'regexp', value: new RegExp(d.join(''), flgs ? flgs.join('') : '') };
+    regex = "/" d:[^/]+ "/" flgs:flags? {
+      // https://github.com/estools/esquery/issues/68
+      const text = d.join('').replaceAll("\\\\x2F", "\\/");
+      return {
+        type: 'regexp', value: new RegExp(text, flgs ? flgs.join('') : '')
+      };
     }
 
 field = "." i:identifierName is:("." identifierName)* {

tests/fixtures/literalSlash.js

@@ -0,0 +1,13 @@
+import * as esprima from 'esprima';
+
+const parsed = esprima.parse(`
+    var s1 = "foo/bar";
+    var s2 = "foo//bar";
+
+    var b1 = "foo\\/bar";
+    var b2 = "foo\\/\\/bar";
+`);
+
+export default parsed;
+
+

tests/queryAttribute.js

@@ -2,6 +2,7 @@ import esquery from '../esquery.js';
 import literal from './fixtures/literal.js';
 import conditional from './fixtures/conditional.js';
 import forLoop from './fixtures/forLoop.js';
+import literalSlash from './fixtures/literalSlash.js';
 import simpleFunction from './fixtures/simpleFunction.js';
 import simpleProgram from './fixtures/simpleProgram.js';
 
@@ -160,6 +161,48 @@ describe('Attribute query', function () {
         ]);
     });
 
+    it('single backslash-escaped slash in a literal', function () {
+        const matches = esquery(literalSlash, '[value="foo\\/bar"]');
+        assert.includeMembers(matches, [
+            literalSlash.body[2].declarations[0].init
+        ]);
+    });
+
+    it('single backslash-escaped slash in a regexp', function () {
+        const matches = esquery(literalSlash, '[value=/foo\\/bar/]');
+        assert.includeMembers(matches, [
+            literalSlash.body[0].declarations[0].init
+        ]);
+    });
+
+    it('single encoded slash in a regexp', function () {
+        const matches = esquery(literalSlash, '[value=/foo\\x2Fbar/]');
+        assert.includeMembers(matches, [
+            literalSlash.body[0].declarations[0].init
+        ]);
+    });
+
+    it('double backslash-escaped slash in a literal', function () {
+        const matches = esquery(literalSlash, '[value="foo\\/\\/bar"]');
+        assert.includeMembers(matches, [
+            literalSlash.body[3].declarations[0].init
+        ]);
+    });
+
+    it('double backslash-escaped slash in a regexp', function () {
+        const matches = esquery(literalSlash, '[value=/foo\\/\\/bar/]');
+        assert.includeMembers(matches, [
+            literalSlash.body[1].declarations[0].init
+        ]);
+    });
+
+    it('double backslash-escaped slash in a regexp', function () {
+        const matches = esquery(literalSlash, '[value=/foo\\x2F\\x2Fbar/]');
+        assert.includeMembers(matches, [
+            literalSlash.body[1].declarations[0].init
+        ]);
+    });
+
     it('multiple regexp flags (i and u)', function () {
         const matches = esquery(simpleProgram, '[name=/\\u{61}|[SDFY]/iu]');
         assert.includeMembers(matches, [