module: fix check for package.json at volume root

This patch converts the "read package scope" algorithm's while loop
into a do-while loop enabling items at the filesystem root dir to
be considered within the scope of a sibling package.json also at the
filesystem root dir.

Fixes: https://github.com/nodejs/node/issues/33438

Co-authored-by: Guy Bedford <guybedford@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/34595
Reviewed-By: Jan Krems <jan.krems@gmail.com>
Reviewed-By: Mary Marchini <oss@mmarchini.me>

1 files changed, 12 insertions, 9 deletions

diff --git a/lib/internal/modules/cjs/loader.js b/lib/internal/modules/cjs/loader.js
index 9aad5318d71..845f8d8f9aa 100644
--- a/lib/internal/modules/cjs/loader.js
+++ b/lib/internal/modules/cjs/loader.js
@@ -46,6 +46,9 @@ const {
   SafeMap,
   SafeWeakMap,
   String,
+  StringPrototypeEndsWith,
+  StringPrototypeIndexOf,
+  StringPrototypeLastIndexOf,
   StringPrototypeMatch,
   StringPrototypeSlice,
   StringPrototypeStartsWith,
@@ -64,6 +67,7 @@ const assert = require('internal/assert');
 const fs = require('fs');
 const internalFS = require('internal/fs/utils');
 const path = require('path');
+const { sep } = path;
 const { emitWarningSync } = require('internal/process/warning');
 const { internalModuleStat } = internalBinding('fs');
 const packageJsonReader = require('internal/modules/package_json_reader');
@@ -296,20 +300,19 @@ function readPackage(requestPath) {
 }
 
 function readPackageScope(checkPath) {
-  const rootSeparatorIndex = checkPath.indexOf(path.sep);
+  const rootSeparatorIndex = StringPrototypeIndexOf(checkPath, sep);
   let separatorIndex;
-  while (
-    (separatorIndex = checkPath.lastIndexOf(path.sep)) > rootSeparatorIndex
-  ) {
-    checkPath = checkPath.slice(0, separatorIndex);
-    if (checkPath.endsWith(path.sep + 'node_modules'))
+  do {
+    separatorIndex = StringPrototypeLastIndexOf(checkPath, sep);
+    checkPath = StringPrototypeSlice(checkPath, 0, separatorIndex);
+    if (StringPrototypeEndsWith(checkPath, sep + 'node_modules'))
       return false;
-    const pjson = readPackage(checkPath);
+    const pjson = readPackage(checkPath + sep);
     if (pjson) return {
+      data: pjson,
       path: checkPath,
-      data: pjson
     };
-  }
+  } while (separatorIndex > rootSeparatorIndex);
   return false;
 }