module: fix require.resolve() crash on non-string paths

Previously, `require.resolve()` could crash when:
- The first parameter was a relative path and
- The `paths` array contained non-string entries

This commit fixes the issue by adding a check in `Module._findPath` to ensure
all elements in `paths` are strings, and adding a validation in `stat` before
calling `InternalModuleStat` to guard against non-string filenames.

lib/internal/modules/cjs/loader.js

@@ -181,6 +181,7 @@ const {
 
 const {
   codes: {
+    ERR_INVALID_ARG_TYPE,
     ERR_INVALID_ARG_VALUE,
     ERR_INVALID_MODULE_SPECIFIER,
     ERR_REQUIRE_CYCLE_MODULE,
@@ -246,6 +247,9 @@ function wrapModuleLoad(request, parent, isMain) {
  * @param {string} filename Absolute path to the file
  */
 function stat(filename) {
+  // Guard against internal bugs where a non-string filename is passed in by mistake.
+  assert(typeof filename === 'string');
+
   filename = path.toNamespacedPath(filename);
   if (statCache !== null) {
     const result = statCache.get(filename);
@@ -738,6 +742,9 @@ Module._findPath = function(request, paths, isMain, conditions = getCjsCondition
   for (let i = 0; i < paths.length; i++) {
     // Don't search further if path doesn't exist
     const curPath = paths[i];
+    if (typeof curPath !== 'string') {
+      throw new ERR_INVALID_ARG_TYPE('paths', 'array of strings', paths);
+    }
     if (insidePath && curPath && _stat(curPath) < 1) {
       continue;
     }

test/parallel/test-require-resolve-invalid-paths.js

@@ -0,0 +1,18 @@
+'use strict';
+
+require('../common');
+const assert = require('assert');
+
+// Test invalid `paths` entries: Ensure non-string entries throw an error
+{
+  const paths = [1, false, null, undefined, () => {}, {}];
+  paths.forEach((value) => {
+    assert.throws(
+      () => require.resolve('.', { paths: [value] }),
+      {
+        name: 'TypeError',
+        code: 'ERR_INVALID_ARG_TYPE',
+      }
+    );
+  });
+}