module: don't search in require.resolve.paths

The paths used by require.resolve() should be treated as
starting points for module resolution, and not actually
searched.

PR-URL: #23683
Fixes: #18408
Refs: #23643
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Michaël Zasso <[email protected]>
Reviewed-By: Matteo Collina <[email protected]>

Author: cjihrig

lib/internal/modules/cjs/loader.js

@@ -584,9 +584,6 @@ Module._resolveFilename = function(request, parent, isMain, options) {
       fakeParent.paths = Module._nodeModulePaths(path);
       const lookupPaths = Module._resolveLookupPaths(request, fakeParent, true);
 
-      if (!paths.includes(path))
-        paths.push(path);
-
       for (var j = 0; j < lookupPaths.length; j++) {
         if (!paths.includes(lookupPaths[j]))
           paths.push(lookupPaths[j]);

test/fixtures/require-resolve.js

@@ -24,11 +24,12 @@ assert.throws(() => {
     require.resolve('three')
   }, /^Error: Cannot find module 'three'$/);
 
-  // However, it can be found if resolution contains the nested index directory.
-  assert.strictEqual(
-    require.resolve('three', { paths: [nestedIndex] }),
-    path.join(nestedIndex, 'three.js')
-  );
+  // If the nested-index directory is provided as a resolve path, 'three'
+  // cannot be found because nested-index is used as a starting point and not
+  // a searched directory.
+  assert.throws(() => {
+    require.resolve('three', { paths: [nestedIndex] })
+  }, /^Error: Cannot find module 'three'$/);
 
   // Resolution from nested index directory also checks node_modules.
   assert.strictEqual(
@@ -50,6 +51,6 @@ assert.throws(() => {
   paths.unshift(nestedNodeModules);
   assert.strictEqual(
     require.resolve('bar', { paths }),
-    path.join(nestedNodeModules, 'bar.js')
+    path.join(nodeModules, 'bar.js')
   );
 }